\input texinfo @c -*-texinfo-*- @setfilename ../../info/tramp @c %**start of header @settitle TRAMP User Manual @c %**end of header @c This is *so* much nicer :) @footnotestyle end @c In the Tramp repository, the version number is auto-frobbed from @c configure.ac, so you should edit that file and run @c "autoconf && ./configure" to change the version number. @c Additionally, flags are set with respect to the Emacs flavor; and @c depending whether Tramp is packaged into (X)Emacs, or standalone. @include trampver.texi @c Macro for formatting a filename according to the respective syntax. @c xxx and yyy are auxiliary macros in order to omit leading and @c trailing whitespace. Not very elegant, but I don't know it better. @c There are subtle differences between texinfo 4.13 and 5.0. We must @c declare two versions of the macro. This will be improved, hopefully. @c Texinfo 5.0. @ifset txicommandconditionals @macro xxx {one} @set \one\ @end macro @macro yyy {one, two} @xxx{x\one\}@c @ifclear x \one\@w{}\two\@c @end ifclear @clear x\one\ @end macro @macro trampfn {method, user, host, localname} @value{prefix}@c @yyy{\method\,@value{postfixhop}}@c @yyy{\user\,@@}@c \host\@value{postfix}\localname\ @end macro @end ifset @c Texinfo 4.13. @ifclear txicommandconditionals @macro xxx {one}@c @set \one\@c @end macro @macro yyy {one, two}@c @xxx{x\one\}@c @ifclear x@c \one\@w{}\two\@c @end ifclear @clear x\one\@c @end macro @macro trampfn {method, user, host, localname}@c @value{prefix}@yyy{\method\,@value{postfixhop}}@yyy{\user\,@@}\host\@value{postfix}\localname\@c @end macro @end ifclear @copying Copyright @copyright{} 1999--2013 Free Software Foundation, Inc. @quotation Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover texts being ``A GNU Manual'', and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled ``GNU Free Documentation License''. (a) The FSF's Back-Cover Text is: ``You have the freedom to copy and modify this GNU manual.'' @end quotation @end copying @c Entries for @command{install-info} to use @dircategory @value{emacsname} network features @direntry * TRAMP: (tramp). Transparent Remote Access, Multiple Protocol @value{emacsname} remote file access via ssh and scp. @end direntry @titlepage @title @value{tramp} version @value{trampver} User Manual @author by Daniel Pittman @author based on documentation by Kai Gro@ss{}johann @page @insertcopying @end titlepage @contents @ifnottex @node Top, Overview, (dir), (dir) @top @value{tramp} version @value{trampver} User Manual This file documents @value{tramp} version @value{trampver}, a remote file editing package for @value{emacsname}. @value{tramp} stands for `Transparent Remote (file) Access, Multiple Protocol'. This package provides remote file editing, similar to @value{ftppackagename}. The difference is that @value{ftppackagename} uses FTP to transfer files between the local and the remote host, whereas @value{tramp} uses a combination of @command{rsh} and @command{rcp} or other work-alike programs, such as @command{ssh}/@command{scp}. You can find the latest version of this document on the web at @uref{http://www.gnu.org/software/tramp/}. @c Pointer to the other Emacs flavor is necessary only in case of @c standalone installation. @ifset installchapter The manual has been generated for @value{emacsname}. @ifinfo If you want to read the info pages for @value{emacsothername}, you should read in @ref{Installation} how to create them. @end ifinfo @ifhtml If you're using the other Emacs flavor, you should read the @uref{@value{emacsotherfilename}, @value{emacsothername}} pages. @end ifhtml @end ifset @ifhtml The latest release of @value{tramp} is available for @uref{ftp://ftp.gnu.org/gnu/tramp/, download}, or you may see @ref{Obtaining Tramp} for more details, including the Git server details. @value{tramp} also has a @uref{http://savannah.gnu.org/projects/tramp/, Savannah Project Page}. @end ifhtml There is a mailing list for @value{tramp}, available at @email{tramp-devel@@gnu.org}, and archived at @uref{http://lists.gnu.org/archive/html/tramp-devel/, the @value{tramp} Mail Archive}. @ifhtml Older archives are located at @uref{http://sourceforge.net/mailarchive/forum.php?forum=tramp-devel, SourceForge Mail Archive} and @uref{http://www.mail-archive.com/emacs-rcp@@ls6.cs.uni-dortmund.de/, The Mail Archive}. @c in HTML output, there's no new paragraph. @*@* @end ifhtml @insertcopying @end ifnottex @menu * Overview:: What @value{tramp} can and cannot do. For the end user: * Obtaining Tramp:: How to obtain @value{tramp}. * History:: History of @value{tramp}. @ifset installchapter * Installation:: Installing @value{tramp} with your @value{emacsname}. @end ifset * Configuration:: Configuring @value{tramp} for use. * Usage:: An overview of the operation of @value{tramp}. * Bug Reports:: Reporting Bugs and Problems. * Frequently Asked Questions:: Questions and answers from the mailing list. For the developer: * Files directories and localnames:: How file names, directories and localnames are mangled and managed. * Traces and Profiles:: How to Customize Traces. * Issues:: Debatable Issues and What Was Decided. * GNU Free Documentation License:: The license for this documentation. * Function Index:: @value{tramp} functions. * Variable Index:: User options and variables. * Concept Index:: An item for each concept. @detailmenu --- The Detailed Node Listing --- @c @ifset installchapter Installing @value{tramp} with your @value{emacsname} * Installation parameters:: Parameters in order to control installation. * Load paths:: How to plug-in @value{tramp} into your environment. @end ifset Configuring @value{tramp} for use * Connection types:: Types of connections made to remote machines. * Inline methods:: Inline methods. * External methods:: External methods. @ifset emacsgvfs * GVFS based methods:: GVFS based external methods. @end ifset @ifset emacsgw * Gateway methods:: Gateway methods. @end ifset * Default Method:: Selecting a default method. * Default User:: Selecting a default user. * Default Host:: Selecting a default host. * Multi-hops:: Connecting to a remote host using multiple hops. * Customizing Methods:: Using Non-Standard Methods. * Customizing Completion:: Selecting config files for user/host name completion. * Password handling:: Reusing passwords for several connections. * Connection caching:: Reusing connection related information. * Predefined connection information:: Setting own connection related information. * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine. * Remote shell setup:: Remote shell setup hints. * Android shell setup:: Android shell setup hints. * Auto-save and Backup:: Auto-save and Backup. * Windows setup hints:: Issues with Cygwin ssh. Using @value{tramp} * Filename Syntax:: @value{tramp} filename conventions. * Filename completion:: Filename completion. * Ad-hoc multi-hops:: Declaring multiple hops in the file name. * Remote processes:: Integration with other @value{emacsname} packages. * Cleanup remote connections:: Cleanup remote connections. How file names, directories and localnames are mangled and managed * Localname deconstruction:: Breaking a localname into its components. @ifset emacs * External packages:: Integration with external Lisp packages. @end ifset @end detailmenu @end menu @node Overview @chapter An overview of @value{tramp} @cindex overview After the installation of @value{tramp} into your @value{emacsname}, you will be able to access files on remote machines as though they were local. Access to the remote file system for editing files, version control, and @code{dired} are transparently enabled. Your access to the remote machine can be with the @command{rsh}, @command{rlogin}, @command{telnet} programs or with any similar connection method. This connection must pass @acronym{ASCII} successfully to be usable but need not be 8-bit clean. The package provides support for @command{ssh} connections out of the box, one of the more common uses of the package. This allows relatively secure access to machines, especially if @command{ftp} access is disabled. Under Windows, @value{tramp} is integrated with the PuTTY package, using the @command{plink} program. The majority of activity carried out by @value{tramp} requires only that the remote login is possible and is carried out at the terminal. In order to access remote files @value{tramp} needs to transfer their content to the local machine temporarily. @value{tramp} can transfer files between the machines in a variety of ways. The details are easy to select, depending on your needs and the machines in question. The fastest transfer methods for large files rely on a remote file transfer package such as @command{rcp}, @command{scp}, @command{rsync} or (under Windows) @command{pscp}. If the remote copy methods are not suitable for you, @value{tramp} also supports the use of encoded transfers directly through the shell. This requires that the @command{mimencode} or @command{uuencode} tools are available on the remote machine. These methods are generally faster for small files. @value{tramp} is still under active development and any problems you encounter, trivial or major, should be reported to the @value{tramp} developers. @xref{Bug Reports}. @subsubheading Behind the scenes @cindex behind the scenes @cindex details of operation @cindex how it works This section tries to explain what goes on behind the scenes when you access a remote file through @value{tramp}. Suppose you type @kbd{C-x C-f} and enter part of an @value{tramp} file name, then hit @kbd{@key{TAB}} for completion. Suppose further that this is the first time that @value{tramp} is invoked for the host in question. Here's what happens: @itemize @item @value{tramp} discovers that it needs a connection to the host. So it invokes @samp{telnet @var{host}} or @samp{rsh @var{host} -l @var{user}} or a similar tool to connect to the remote host. Communication with this process happens through an @value{emacsname} buffer, that is, the output from the remote end goes into a buffer. @item The remote host may prompt for a login name (for @command{telnet}). The login name is given in the file name, so @value{tramp} sends the login name and a newline. @item The remote host may prompt for a password or pass phrase (for @command{rsh} or for @command{telnet} after sending the login name). @value{tramp} displays the prompt in the minibuffer, asking you for the password or pass phrase. You enter the password or pass phrase. @value{tramp} sends it to the remote host, followed by a newline. @item @value{tramp} now waits for the shell prompt or for a message that the login failed. If @value{tramp} sees neither of them after a certain period of time (a minute, say), then it issues an error message saying that it couldn't find the remote shell prompt and shows you what the remote host has sent. If @value{tramp} sees a @samp{login failed} message, it tells you so, aborts the login attempt and allows you to try again. @item Suppose that the login was successful and @value{tramp} sees the shell prompt from the remote host. Now @value{tramp} invokes @command{/bin/sh} because Bourne shells and C shells have different command syntaxes.@footnote{Invoking @command{/bin/sh} will fail if your login shell doesn't recognize @samp{exec /bin/sh} as a valid command. Maybe you use the Scheme shell @command{scsh}@dots{}} After the Bourne shell has come up, @value{tramp} sends a few commands to ensure a good working environment. It turns off echoing, it sets the shell prompt, and a few other things. @item Now the remote shell is up and it good working order. Remember, what was supposed to happen is that @value{tramp} tries to find out what files exist on the remote host so that it can do filename completion. So, @value{tramp} basically issues @command{cd} and @command{ls} commands and also sometimes @command{echo} with globbing. Another command that is often used is @command{test} to find out whether a file is writable or a directory or the like. The output of each command is parsed for the necessary operation. @item Suppose you are finished with filename completion, have entered @kbd{C-x C-f}, a full file name and hit @kbd{@key{RET}}. Now comes the time to transfer the file contents from the remote host to the local host so that you can edit them. See above for an explanation of how @value{tramp} transfers the file contents. For inline transfers, @value{tramp} issues a command like @samp{mimencode -b /path/to/remote/file}, waits until the output has accumulated in the buffer that's used for communication, then decodes that output to produce the file contents. For external transfers, @value{tramp} issues a command like the following: @example rcp user@@host:/path/to/remote/file /tmp/tramp.4711 @end example It then reads the local temporary file @file{/tmp/tramp.4711} into a buffer and deletes the temporary file. @item You now edit the buffer contents, blithely unaware of what has happened behind the scenes. (Unless you have read this section, that is.) When you are finished, you type @kbd{C-x C-s} to save the buffer. @item Again, @value{tramp} transfers the file contents to the remote host either inline or external. This is the reverse of what happens when reading the file. @end itemize I hope this has provided you with a basic overview of what happens behind the scenes when you open a file with @value{tramp}. @c For the end user @node Obtaining Tramp @chapter Obtaining Tramp. @cindex obtaining Tramp @value{tramp} is freely available on the Internet and the latest release may be downloaded from @uref{ftp://ftp.gnu.org/gnu/tramp/}. This release includes the full documentation and code for @value{tramp}, suitable for installation. But Emacs (22 or later) includes @value{tramp} already, and there is a @value{tramp} package for XEmacs, as well. So maybe it is easier to just use those. But if you want the bleeding edge, read on@dots{} For the especially brave, @value{tramp} is available from Git. The Git version is the latest version of the code and may contain incomplete features or new issues. Use these versions at your own risk. Instructions for obtaining the latest development version of @value{tramp} from Git can be found by going to the Savannah project page at the following URL and then clicking on the Git link in the navigation bar at the top. @noindent @uref{http://savannah.gnu.org/projects/tramp/} @noindent Or follow the example session below: @example ] @strong{cd ~/@value{emacsdir}} ] @strong{git clone git://git.savannah.gnu.org/tramp.git} @end example @noindent Tramp developers use instead @example ] @strong{git clone login@@git.sv.gnu.org:/srv/git/tramp.git} @end example @noindent You should now have a directory @file{~/@value{emacsdir}/tramp} containing the latest version of @value{tramp}. You can fetch the latest updates from the repository by issuing the command: @example ] @strong{cd ~/@value{emacsdir}/tramp} ] @strong{git pull} @end example @noindent Once you've got updated files from the Git repository, you need to run @command{autoconf} in order to get an up-to-date @file{configure} script: @example ] @strong{cd ~/@value{emacsdir}/tramp} ] @strong{autoconf} @end example @node History @chapter History of @value{tramp} @cindex history @cindex development history Development was started end of November 1998. The package was called @file{rssh.el}, back then. It only provided one method to access a file, using @command{ssh} to log in to a remote host and using @command{scp} to transfer the file contents. After a while, the name was changed to @file{rcp.el}, and now it's @value{tramp}. Along the way, many more methods for getting a remote shell and for transferring the file contents were added. Support for VC was added. After that, there were added the multi-hop methods in April 2000 and the unification of @value{tramp} and Ange-FTP filenames in July 2002. In July 2004, multi-hop methods have been replaced by proxy hosts. Running commands on remote hosts was introduced in December 2005. @ifset emacsgw Support of gateways exists since April 2007. @end ifset @ifset emacsgvfs GVFS integration started in February 2009. @end ifset @ifset emacs Remote commands on Windows hosts are available since September 2011. @end ifset Ad-hoc multi-hop methods (with a changed syntax) have been reenabled in November 2011. In November 2012, Juergen Hoetzel's @file{tramp-adb.el} has been added. In December 2001, @value{tramp} has been added to the XEmacs package repository. Being part of the Emacs repository happened in June 2002, the first release including @value{tramp} was Emacs 22.1. @value{tramp} is also a Debian GNU/Linux package since February 2001. @c Installation chapter is necessary only in case of standalone @c installation. Text taken from trampinst.texi. @ifset installchapter @include trampinst.texi @end ifset @node Configuration @chapter Configuring @value{tramp} for use @cindex configuration @cindex default configuration @value{tramp} is (normally) fully functional when it is initially installed. It is initially configured to use the @command{scp} program to connect to the remote host. So in the easiest case, you just type @kbd{C-x C-f} and then enter the filename @file{@trampfn{, user, machine, /path/to.file}}. On some hosts, there are problems with opening a connection. These are related to the behavior of the remote shell. See @xref{Remote shell setup}, for details on this. If you do not wish to use these commands to connect to the remote host, you should change the default connection and transfer method that @value{tramp} uses. There are several different methods that @value{tramp} can use to connect to remote machines and transfer files (@pxref{Connection types}). If you don't know which method is right for you, see @xref{Default Method}. @menu * Connection types:: Types of connections made to remote machines. * Inline methods:: Inline methods. * External methods:: External methods. @ifset emacsgvfs * GVFS based methods:: GVFS based external methods. @end ifset @ifset emacsgw * Gateway methods:: Gateway methods. @end ifset * Default Method:: Selecting a default method. Here we also try to help those who don't have the foggiest which method is right for them. * Default User:: Selecting a default user. * Default Host:: Selecting a default host. * Multi-hops:: Connecting to a remote host using multiple hops. * Customizing Methods:: Using Non-Standard Methods. * Customizing Completion:: Selecting config files for user/host name completion. * Password handling:: Reusing passwords for several connections. * Connection caching:: Reusing connection related information. * Predefined connection information:: Setting own connection related information. * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine. * Remote shell setup:: Remote shell setup hints. * Android shell setup:: Android shell setup hints. * Auto-save and Backup:: Auto-save and Backup. * Windows setup hints:: Issues with Cygwin ssh. @end menu @node Connection types @section Types of connections made to remote machines @cindex connection types, overview There are two basic types of transfer methods, each with its own advantages and limitations. Both types of connection make use of a remote shell access program such as @command{rsh}, @command{ssh} or @command{telnet} to connect to the remote machine. This connection is used to perform many of the operations that @value{tramp} requires to make the remote file system transparently accessible from the local machine. It is only when visiting files that the methods differ. @cindex inline methods @cindex external methods @cindex methods, inline @cindex methods, external Loading or saving a remote file requires that the content of the file be transferred between the two machines. The content of the file can be transferred using one of two methods: the @dfn{inline method} over the same connection used to log in to the remote machine, or the @dfn{external method} through another connection using a remote copy program such as @command{rcp}, @command{scp} or @command{rsync}. The performance of the external methods is generally better than that of the inline methods, at least for large files. This is caused by the need to encode and decode the data when transferring inline. The one exception to this rule are the @command{scp} based transfer methods. While these methods do see better performance when actually transferring files, the overhead of the cryptographic negotiation at startup may drown out the improvement in file transfer times. External methods should be configured such a way that they don't require a password (with @command{ssh-agent}, or such alike). Modern @command{scp} implementations offer options to reuse existing @command{ssh} connections, which will be enabled by default if available. If it isn't possible, you should consider @ref{Password handling}, otherwise you will be prompted for a password every copy action. @node Inline methods @section Inline methods @cindex inline methods @cindex methods, inline The inline methods in @value{tramp} are quite powerful and can work in situations where you cannot use an external transfer program to connect. Inline methods are the only methods that work when connecting to the remote machine via telnet. (There are also strange inline methods which allow you to transfer files between @emph{user identities} rather than hosts, see below.) These methods depend on the existence of a suitable encoding and decoding command on remote machine. Locally, @value{tramp} may be able to use features of @value{emacsname} to decode and encode the files or it may require access to external commands to perform that task. @cindex uuencode @cindex mimencode @cindex base-64 encoding @value{tramp} checks the availability and usability of commands like @command{mimencode} (part of the @command{metamail} package) or @command{uuencode} on the remote host. The first reliable command will be used. The search path can be customized, see @ref{Remote Programs}. If both commands aren't available on the remote host, @value{tramp} transfers a small piece of Perl code to the remote host, and tries to apply it for encoding and decoding. The variable @var{tramp-inline-compress-start-size} controls, whether a file shall be compressed before encoding. This could increase transfer speed for large text files. @table @asis @item @option{rsh} @cindex method rsh @cindex rsh method Connect to the remote host with @command{rsh}. Due to the unsecure connection it is recommended for very local host topology only. On operating systems which provide the command @command{remsh} instead of @command{rsh}, you can use the method @option{remsh}. This is true for HP-UX or Cray UNICOS, for example. @item @option{ssh} @cindex method ssh @cindex ssh method Connect to the remote host with @command{ssh}. This is identical to the previous option except that the @command{ssh} package is used, making the connection more secure. All the methods based on @command{ssh} have an additional feature: you can specify a host name which looks like @file{host#42} (the real host name, then a hash sign, then a port number). This means to connect to the given host but to also pass @code{-p 42} as arguments to the @command{ssh} command. @item @option{telnet} @cindex method telnet @cindex telnet method Connect to the remote host with @command{telnet}. This is as unsecure as the @option{rsh} method. @item @option{su} @cindex method su @cindex su method This method does not connect to a remote host at all, rather it uses the @command{su} program to allow you to edit files as another user. That means, the specified host name in the file name must be either @samp{localhost} or the host name as returned by the function @command{(system-name)}. For an exception of this rule see @ref{Multi-hops}. @item @option{sudo} @cindex method sudo @cindex sudo method This is similar to the @option{su} method, but it uses @command{sudo} rather than @command{su} to become a different user. Note that @command{sudo} must be configured to allow you to start a shell as the user. It would be nice if it was sufficient if @command{ls} and @command{mimencode} were allowed, but that is not easy to implement, so I haven't got around to it, yet. @item @option{sshx} @cindex method sshx @cindex sshx method As you would expect, this is similar to @option{ssh}, only a little different. Whereas @option{ssh} opens a normal interactive shell on the remote host, this option uses @samp{ssh -t -t @var{host} -l @var{user} /bin/sh} to open a connection. This is useful for users where the normal login shell is set up to ask them a number of questions when logging in. This procedure avoids these questions, and just gives @value{tramp} a more-or-less `standard' login shell to work with. Note that this procedure does not eliminate questions asked by @command{ssh} itself. For example, @command{ssh} might ask ``Are you sure you want to continue connecting?'' if the host key of the remote host is not known. @value{tramp} does not know how to deal with such a question (yet), therefore you will need to make sure that you can log in without such questions. This is also useful for Windows users where @command{ssh}, when invoked from an @value{emacsname} buffer, tells them that it is not allocating a pseudo tty. When this happens, the login shell is wont to not print any shell prompt, which confuses @value{tramp} mightily. This supports the @samp{-p} argument. @item @option{krlogin} @cindex method krlogin @cindex krlogin method @cindex Kerberos (with krlogin method) This method is also similar to @option{ssh}. It only uses the @command{krlogin -x} command to log in to the remote host. @item @option{ksu} @cindex method ksu @cindex ksu method @cindex Kerberos (with ksu method) This is another method from the Kerberos suite. It behaves like @option{su}. @item @option{plink} @cindex method plink @cindex plink method This method is mostly interesting for Windows users using the PuTTY implementation of SSH@. It uses @samp{plink -ssh} to log in to the remote host. This supports the @samp{-P} argument. @item @option{plinkx} @cindex method plinkx @cindex plinkx method Another method using PuTTY on Windows. Instead of host names, it expects PuTTY session names, calling @samp{plink -load @var{session} -t"}. User names are relevant only in case the corresponding session hasn't defined a user name. Different port numbers must be defined in the session. @end table @node External methods @section External methods @cindex methods, external @cindex external methods The external methods operate through multiple channels, using the remote shell connection for many actions while delegating file transfers to an external transfer utility. This saves the overhead of encoding and decoding that multiplexing the transfer through the one connection has with the inline methods. Since external methods need their own overhead opening a new channel, all files which are smaller than @var{tramp-copy-size-limit} are still transferred with the corresponding inline method. It should provide a fair trade-off between both approaches. @table @asis @item @option{rcp}---@command{rsh} and @command{rcp} @cindex method rcp @cindex rcp method @cindex rcp (with rcp method) @cindex rsh (with rcp method) This method uses the @command{rsh} and @command{rcp} commands to connect to the remote machine and transfer files. This is probably the fastest connection method available. The alternative method @option{remcp} uses the @command{remsh} and @command{rcp} commands. It should be applied on machines where @command{remsh} is used instead of @command{rsh}. @item @option{scp}---@command{ssh} and @command{scp} @cindex method scp @cindex scp method @cindex scp (with scp method) @cindex ssh (with scp method) Using @command{ssh} to connect to the remote host and @command{scp} to transfer files between the machines is the best method for securely connecting to a remote machine and accessing files. The performance of this option is also quite good. It may be slower than the inline methods when you often open and close small files however. The cost of the cryptographic handshake at the start of an @command{scp} session can begin to absorb the advantage that the lack of encoding and decoding presents. All the @command{ssh} based methods support the @samp{-p} feature where you can specify a port number to connect to in the host name. For example, the host name @file{host#42} tells @value{tramp} to specify @samp{-p 42} in the argument list for @command{ssh}, and to specify @samp{-P 42} in the argument list for @command{scp}. @item @option{sftp}---@command{ssh} and @command{sftp} @cindex method sftp @cindex sftp method @cindex sftp (with sftp method) @cindex ssh (with sftp method) That is mostly the same method as @option{scp}, but using @command{sftp} as transfer command. So the same remarks are valid. This command does not work like @value{ftppackagename}, where @command{ftp} is called interactively, and all commands are send from within this session. Instead of, @command{ssh} is used for login. This method supports the @samp{-p} argument. @item @option{rsync}---@command{ssh} and @command{rsync} @cindex method rsync @cindex rsync method @cindex rsync (with rsync method) @cindex ssh (with rsync method) Using the @command{ssh} command to connect securely to the remote machine and the @command{rsync} command to transfer files is almost identical to the @option{scp} method. While @command{rsync} performs much better than @command{scp} when transferring files that exist on both hosts, this advantage is lost if the file exists only on one side of the connection. A file can exists on both the remote and local host, when you copy a file from/to a remote host. When you just open a file from the remote host (or write a file there), a temporary file on the local side is kept as long as the corresponding buffer, visiting this file, is alive. This method supports the @samp{-p} argument. @item @option{scpx}---@command{ssh} and @command{scp} @cindex method scpx @cindex scpx method @cindex scp (with scpx method) @cindex ssh (with scpx method) As you would expect, this is similar to @option{scp}, only a little different. Whereas @option{scp} opens a normal interactive shell on the remote host, this option uses @samp{ssh -t -t @var{host} -l @var{user} /bin/sh} to open a connection. This is useful for users where the normal login shell is set up to ask them a number of questions when logging in. This procedure avoids these questions, and just gives @value{tramp} a more-or-less `standard' login shell to work with. This is also useful for Windows users where @command{ssh}, when invoked from an @value{emacsname} buffer, tells them that it is not allocating a pseudo tty. When this happens, the login shell is wont to not print any shell prompt, which confuses @value{tramp} mightily. This method supports the @samp{-p} argument. @item @option{pscp}---@command{plink} and @command{pscp} @cindex method pscp @cindex pscp method @cindex pscp (with pscp method) @cindex plink (with pscp method) @cindex PuTTY (with pscp method) This method is similar to @option{scp}, but it uses the @command{plink} command to connect to the remote host, and it uses @command{pscp} for transferring the files. These programs are part of PuTTY, an SSH implementation for Windows. This method supports the @samp{-P} argument. @item @option{psftp}---@command{plink} and @command{psftp} @cindex method psftp @cindex psftp method @cindex psftp (with psftp method) @cindex plink (with psftp method) @cindex PuTTY (with psftp method) As you would expect, this method is similar to @option{sftp}, but it uses the @command{plink} command to connect to the remote host, and it uses @command{psftp} for transferring the files. These programs are part of PuTTY, an SSH implementation for Windows. This method supports the @samp{-P} argument. @item @option{fcp}---@command{fsh} and @command{fcp} @cindex method fcp @cindex fcp method @cindex fsh (with fcp method) @cindex fcp (with fcp method) This method is similar to @option{scp}, but it uses the @command{fsh} command to connect to the remote host, and it uses @command{fcp} for transferring the files. @command{fsh/fcp} are a front-end for @command{ssh} which allow for reusing the same @command{ssh} session for submitting several commands. This avoids the startup overhead of @command{scp} (which has to establish a secure connection whenever it is called). Note, however, that you can also use one of the inline methods to achieve a similar effect. This method uses the command @samp{fsh @var{host} -l @var{user} /bin/sh -i} to establish the connection, it does not work to just say @command{fsh @var{host} -l @var{user}}. @cindex method fsh @cindex fsh method There is no inline method using @command{fsh} as the multiplexing provided by the program is not very useful in our context. @value{tramp} opens just one connection to the remote host and then keeps it open, anyway. @item @option{ftp} @cindex method ftp @cindex ftp method This is not a native @value{tramp} method. Instead, it forwards all requests to @value{ftppackagename}. @ifset xemacs This works only for unified filenames, see @ref{Issues}. @end ifset @item @option{smb}---@command{smbclient} @cindex method smb @cindex smb method This is another not native @value{tramp} method. It uses the @command{smbclient} command on different Unices in order to connect to an SMB server. An SMB server might be a Samba (or CIFS) server on another UNIX host or, more interesting, a host running MS Windows. So far, it is tested against MS Windows NT, MS Windows 2000, MS Windows XP, MS Windows Vista, and MS Windows 7. The first directory in the localname must be a share name on the remote host. Remember that the @code{$} character, in which default shares usually end, must be written @code{$$} due to environment variable substitution in file names. If no share name is given (i.e., remote directory @code{/}), all available shares are listed. Since authorization is done on share level, you will always be prompted for a password if you access another share on the same host. This can be suppressed by @ref{Password handling}. For authorization, MS Windows uses both a user name and a domain name. Because of this, the @value{tramp} syntax has been extended: you can specify a user name which looks like @code{user%domain} (the real user name, then a percent sign, then the domain name). So, to connect to the machine @code{melancholia} as user @code{daniel} of the domain @code{BIZARRE}, and edit @file{.emacs} in the home directory (share @code{daniel$}) I would specify the filename @file{@trampfn{smb, daniel%BIZARRE, melancholia, /daniel$$/.emacs}}. Depending on the Windows domain configuration, a Windows user might be considered as domain user per default. In order to connect as local user, the WINS name of that machine must be given as domain name. Usually, it is the machine name in capital letters. In the example above, the local user @code{daniel} would be specified as @file{@trampfn{smb, daniel%MELANCHOLIA, melancholia, /daniel$$/.emacs}}. The domain name as well as the user name are optional. If no user name is specified at all, the anonymous user (without password prompting) is assumed. This is different from all other @value{tramp} methods, where in such a case the local user name is taken. The @option{smb} method supports the @samp{-p} argument. @strong{Please note:} If @value{emacsname} runs locally under MS Windows, this method isn't available. Instead, you can use UNC file names like @file{//melancholia/daniel$$/.emacs}. The only disadvantage is that there's no possibility to specify another user name. @item @option{adb} @cindex method adb @cindex adb method This special method uses the Android Debug Bridge for accessing Android devices. The Android Debug Bridge must be installed locally. Some GNU/Linux distributions offer it for installation, otherwise it can be installed as part of the Android SDK. If the @command{adb} program is not found via the @env{PATH} environment variable, the variable @var{tramp-adb-program} must point to its absolute path. Tramp does not connect Android devices to @command{adb}. This must be performed outside @value{emacsname}. If there is exactly one Android device connected to @command{adb}, a host name is not needed in the remote file name. The default @value{tramp} name to be used is @file{@trampfn{adb, , ,}} therefore. Otherwise, one could find potential host names with the command @command{adb devices}. Usually, the @command{adb} method does not need any user name. It runs under the permissions of the @command{adbd} process on the Android device. If a user name is specified, @value{tramp} applies an @command{su} on the device. This does not work with all Android devices, especially with unrooted ones. In that case, an error message is displayed. @end table @ifset emacsgvfs @node GVFS based methods @section GVFS based external methods @cindex methods, gvfs @cindex gvfs based methods @cindex dbus The connection methods described in this section are based on GVFS @uref{http://en.wikipedia.org/wiki/GVFS}. Via GVFS, the remote filesystem is mounted locally through FUSE@. @value{tramp} uses this local mounted directory internally. The communication with GVFS is implemented via D-Bus messages. Therefore, your @value{emacsname} must have D-Bus integration, @pxref{Top, , D-Bus, dbus}. @table @asis @item @option{dav} @cindex method dav @cindex method davs @cindex dav method @cindex davs method This method provides access to WebDAV files and directories. There exists also the external method @option{davs}, which uses SSL encryption for the access. Both methods support the port number specification as discussed above. @item @option{obex} @cindex method obex @cindex obex method OBEX is an FTP-like access protocol for simple devices, like cell phones. For the time being, @value{tramp} only supports OBEX over Bluetooth. @item @option{synce} @cindex method synce @cindex synce method The @option{synce} method allows communication with Windows Mobile devices. Beside GVFS for mounting remote files and directories via FUSE, it also needs the SYNCE-GVFS plugin. @end table @defopt tramp-gvfs-methods This customer option, a list, defines the external methods which shall be used with GVFS@. Per default, these are @option{dav}, @option{davs}, @option{obex} and @option{synce}. Other possible values are @option{ftp}, @option{sftp} and @option{smb}. @end defopt @end ifset @ifset emacsgw @node Gateway methods @section Gateway methods @cindex methods, gateway @cindex gateway methods Gateway methods are not methods to access a remote host directly. These methods are intended to pass firewalls or proxy servers. Therefore, they can be used for proxy host declarations (@pxref{Multi-hops}) only. A gateway method must always come along with a method which supports port setting. This is because @value{tramp} targets the accompanied method to @file{localhost#random_port}, from where the firewall or proxy server is accessed. Gateway methods support user name and password declarations. These are used to authenticate towards the corresponding firewall or proxy server. They can be passed only if your friendly administrator has granted your access. @table @asis @item @option{tunnel} @cindex method tunnel @cindex tunnel method This method implements an HTTP tunnel via the @command{CONNECT} command (see RFC 2616, 2817). Any HTTP 1.1 compliant (proxy) server shall support this command. As authentication method, only @option{Basic Authentication} (see RFC 2617) is implemented so far. If no port number is given in the declaration, port @option{8080} is used for the proxy server. @item @option{socks} @cindex method socks @cindex socks method The @command{socks} method provides access to SOCKSv5 servers (see RFC 1928). @option{Username/Password Authentication} according to RFC 1929 is supported. The default port number of the socks server is @option{1080}, if not specified otherwise. @end table @end ifset @node Default Method @section Selecting a default method @cindex default method @vindex tramp-default-method When you select an appropriate transfer method for your typical usage you should set the variable @code{tramp-default-method} to reflect that choice. This variable controls which method will be used when a method is not specified in the @value{tramp} file name. For example: @lisp (setq tramp-default-method "ssh") @end lisp @vindex tramp-default-method-alist You can also specify different methods for certain user/host combinations, via the variable @code{tramp-default-method-alist}. For example, the following two lines specify to use the @option{ssh} method for all user names matching @samp{john} and the @option{rsync} method for all host names matching @samp{lily}. The third line specifies to use the @option{su} method for the user @samp{root} on the machine @samp{localhost}. @lisp (add-to-list 'tramp-default-method-alist '("" "john" "ssh")) (add-to-list 'tramp-default-method-alist '("lily" "" "rsync")) (add-to-list 'tramp-default-method-alist '("\\`localhost\\'" "\\`root\\'" "su")) @end lisp @noindent See the documentation for the variable @code{tramp-default-method-alist} for more details. External methods are normally preferable to inline methods, giving better performance. @xref{Inline methods}. @xref{External methods}. Another consideration with the selection of transfer methods is the environment you will use them in and, especially when used over the Internet, the security implications of your preferred method. The @option{rsh} and @option{telnet} methods send your password as plain text as you log in to the remote machine, as well as transferring the files in such a way that the content can easily be read from other machines. If you need to connect to remote systems that are accessible from the Internet, you should give serious thought to using @option{ssh} based methods to connect. These provide a much higher level of security, making it a non-trivial exercise for someone to obtain your password or read the content of the files you are editing. @subsection Which method is the right one for me? @cindex choosing the right method Given all of the above, you are probably thinking that this is all fine and good, but it's not helping you to choose a method! Right you are. As a developer, we don't want to boss our users around but give them maximum freedom instead. However, the reality is that some users would like to have some guidance, so here I'll try to give you this guidance without bossing you around. You tell me whether it works @dots{} My suggestion is to use an inline method. For large files, external methods might be more efficient, but I guess that most people will want to edit mostly small files. And if you access large text files, compression (driven by @var{tramp-inline-compress-start-size}) shall still result in good performance. I guess that these days, most people can access a remote machine by using @command{ssh}. So I suggest that you use the @option{ssh} method. So, type @kbd{C-x C-f @trampfn{ssh, root, otherhost, /etc/motd} @key{RET}} to edit the @file{/etc/motd} file on the other host. If you can't use @option{ssh} to log in to the remote host, then select a method that uses a program that works. For instance, Windows users might like the @option{plink} method which uses the PuTTY implementation of @command{ssh}. Or you use Kerberos and thus like @option{krlogin}. For the special case of editing files on the local host as another user, see the @option{su} or @option{sudo} methods. They offer shortened syntax for the @samp{root} account, like @file{@trampfn{su, , , /etc/motd}}. People who edit large files may want to consider @option{scp} instead of @option{ssh}, or @option{pscp} instead of @option{plink}. These external methods are faster than inline methods for large files. Note, however, that external methods suffer from some limitations. Please try first whether you really get a noticeable speed advantage from using an external method! Maybe even for large files, inline methods are fast enough. @node Default User @section Selecting a default user @cindex default user The user part of a @value{tramp} file name can be omitted. Usually, it is replaced by the user name you are logged in. Often, this is not what you want. A typical use of @value{tramp} might be to edit some files with root permissions on the local host. This case, you should set the variable @code{tramp-default-user} to reflect that choice. For example: @lisp (setq tramp-default-user "root") @end lisp @code{tramp-default-user} is regarded as obsolete, and will be removed soon. @vindex tramp-default-user-alist You can also specify different users for certain method/host combinations, via the variable @code{tramp-default-user-alist}. For example, if you always have to use the user @samp{john} in the domain @samp{somewhere.else}, you can specify the following: @lisp (add-to-list 'tramp-default-user-alist '("ssh" ".*\\.somewhere\\.else\\'" "john")) @end lisp @noindent See the documentation for the variable @code{tramp-default-user-alist} for more details. One trap to fall in must be known. If @value{tramp} finds a default user, this user will be passed always to the connection command as parameter (for example @command{ssh here.somewhere.else -l john}. If you have specified another user for your command in its configuration files, @value{tramp} cannot know it, and the remote access will fail. If you have specified in the given example in @file{~/.ssh/config} the lines @example Host here.somewhere.else User lily @end example @noindent than you must discard selecting a default user by @value{tramp}. This will be done by setting it to @code{nil} (or @samp{lily}, likewise): @lisp (add-to-list 'tramp-default-user-alist '("ssh" "\\`here\\.somewhere\\.else\\'" nil)) @end lisp The last entry in @code{tramp-default-user-alist} could be your default user you'll apply predominantly. You shall @emph{append} it to that list at the end: @lisp (add-to-list 'tramp-default-user-alist '(nil nil "jonas") t) @end lisp @node Default Host @section Selecting a default host @cindex default host @vindex tramp-default-host Finally, it is even possible to omit the host name part of a @value{tramp} file name. This case, the value of the variable @code{tramp-default-host} is used. Per default, it is initialized with the host name your local @value{emacsname} is running. If you, for example, use @value{tramp} mainly to contact the host @samp{target} as user @samp{john}, you can specify: @lisp (setq tramp-default-user "john" tramp-default-host "target") @end lisp Then the simple file name @samp{@trampfn{ssh, , ,}} will connect you to John's home directory on target. @ifset emacs Note, however, that the most simplification @samp{/::} won't work, because @samp{/:} is the prefix for quoted file names. @end ifset @vindex tramp-default-host-alist Like with methods and users, you can also specify different default hosts for certain method/user combinations via the variable @code{tramp-default-host-alist}. Usually, this isn't necessary, because @code{tramp-default-host} should be sufficient. For some methods, like @option{adb}, that default value must be overwritten, which is already the initial value of @code{tramp-default-host-alist}. @noindent See the documentation for the variable @code{tramp-default-host-alist} for more details. @node Multi-hops @section Connecting to a remote host using multiple hops @cindex multi-hop @cindex proxy hosts Sometimes, the methods described before are not sufficient. Sometimes, it is not possible to connect to a remote host using a simple command. For example, if you are in a secured network, you might have to log in to a bastion host first before you can connect to the outside world. Of course, the target host may also require a bastion host. @vindex tramp-default-proxies-alist @defopt tramp-default-proxies-alist In order to specify multiple hops, it is possible to define a proxy host to pass through, via the variable @code{tramp-default-proxies-alist}. This variable keeps a list of triples (@var{host} @var{user} @var{proxy}). The first matching item specifies the proxy host to be passed for a file name located on a remote target matching @var{user}@@@var{host}. @var{host} and @var{user} are regular expressions or @code{nil}, which is interpreted as a regular expression which always matches. @var{proxy} must be a Tramp filename which localname part is ignored. Method and user name on @var{proxy} are optional, which is interpreted with the default values. @ifset emacsgw The method must be an inline or gateway method (@pxref{Inline methods}, @pxref{Gateway methods}). @end ifset @ifclear emacsgw The method must be an inline method (@pxref{Inline methods}). @end ifclear If @var{proxy} is @code{nil}, no additional hop is required reaching @var{user}@@@var{host}. If you, for example, must pass the host @samp{bastion.your.domain} as user @samp{bird} for any remote host which is not located in your local domain, you can set @lisp (add-to-list 'tramp-default-proxies-alist '("\\." nil "@trampfn{ssh, bird, bastion.your.domain,}")) (add-to-list 'tramp-default-proxies-alist '("\\.your\\.domain\\'" nil nil)) @end lisp Please note the order of the code. @code{add-to-list} adds elements at the beginning of a list. Therefore, most relevant rules must be added last. Proxy hosts can be cascaded. If there is another host called @samp{jump.your.domain}, which is the only one in your local domain who is allowed connecting @samp{bastion.your.domain}, you can add another rule: @lisp (add-to-list 'tramp-default-proxies-alist '("\\`bastion\\.your\\.domain\\'" "\\`bird\\'" "@trampfn{ssh, , jump.your.domain,}")) @end lisp @var{proxy} can contain the patterns @code{%h} or @code{%u}. These patterns are replaced by the strings matching @var{host} or @var{user}, respectively. If you, for example, wants to work as @samp{root} on hosts in the domain @samp{your.domain}, but login as @samp{root} is disabled for non-local access, you might add the following rule: @lisp (add-to-list 'tramp-default-proxies-alist '("\\.your\\.domain\\'" "\\`root\\'" "@trampfn{ssh, , %h,}")) @end lisp Opening @file{@trampfn{sudo, , randomhost.your.domain,}} would connect first @samp{randomhost.your.domain} via @code{ssh} under your account name, and perform @code{sudo -u root} on that host afterwards. It is important to know that the given method is applied on the host which has been reached so far. @code{sudo -u root}, applied on your local host, wouldn't be useful here. @var{host}, @var{user} and @var{proxy} can also be Lisp forms. These forms are evaluated, and must return a string, or @code{nil}. The previous example could be generalized then: For all hosts except my local one connect via @command{ssh} first, and apply @command{sudo -u root} afterwards: @lisp (add-to-list 'tramp-default-proxies-alist '(nil "\\`root\\'" "@trampfn{ssh, , %h,}")) (add-to-list 'tramp-default-proxies-alist '((regexp-quote (system-name)) nil nil)) @end lisp This is the recommended configuration to work as @samp{root} on remote Ubuntu hosts. @ifset emacsgw Finally, @code{tramp-default-proxies-alist} can be used to pass firewalls or proxy servers. Imagine your local network has a host @samp{proxy.your.domain} which is used on port 3128 as HTTP proxy to the outer world. Your friendly administrator has granted you access under your user name to @samp{host.other.domain} on that proxy server.@footnote{HTTP tunnels are intended for secure SSL/TLS communication. Therefore, many proxy server restrict the tunnels to related target ports. You might need to run your ssh server on your target host @samp{host.other.domain} on such a port, like 443 (https). See @uref{http://savannah.gnu.org/maintenance/CvsFromBehindFirewall} for discussion of ethical issues.} You would need to add the following rule: @lisp (add-to-list 'tramp-default-proxies-alist '("\\`host\\.other\\.domain\\'" nil "@trampfn{tunnel, , proxy.your.domain#3128,}")) @end lisp Gateway methods can be declared as first hop only in a multiple hop chain. @end ifset @end defopt Hops to be passed tend to be restricted firewalls and alike. Sometimes they offer limited features only, like running @command{rbash} (restricted bash). This must be told to @value{tramp}. @vindex tramp-restricted-shell-hosts-alist @defopt tramp-restricted-shell-hosts-alist This variable keeps a list of regular expressions, which denote hosts running a registered shell like "rbash". Those hosts can be used as proxies only. If the bastion host from the example above runs a restricted shell, you shall apply @lisp (add-to-list 'tramp-restricted-shell-hosts-alist "\\`bastion\\.your\\.domain\\'") @end lisp @end defopt @node Customizing Methods @section Using Non-Standard Methods @cindex customizing methods @cindex using non-standard methods @cindex create your own methods There is a variable @code{tramp-methods} which you can change if the predefined methods don't seem right. For the time being, I'll refer you to the Lisp documentation of that variable, accessible with @kbd{C-h v tramp-methods @key{RET}}. @node Customizing Completion @section Selecting config files for user/host name completion @cindex customizing completion @cindex selecting config files @vindex tramp-completion-function-alist The variable @code{tramp-completion-function-alist} is intended to customize which files are taken into account for user and host name completion (@pxref{Filename completion}). For every method, it keeps a set of configuration files, accompanied by a Lisp function able to parse that file. Entries in @code{tramp-completion-function-alist} have the form (@var{method} @var{pair1} @var{pair2} ...). Each @var{pair} is composed of (@var{function} @var{file}). @var{function} is responsible to extract user names and host names from @var{file} for completion. There are two functions which access this variable: @defun tramp-get-completion-function method This function returns the list of completion functions for @var{method}. Example: @example (tramp-get-completion-function "rsh") @result{} ((tramp-parse-rhosts "/etc/hosts.equiv") (tramp-parse-rhosts "~/.rhosts")) @end example @end defun @defun tramp-set-completion-function method function-list This function sets @var{function-list} as list of completion functions for @var{method}. Example: @example (tramp-set-completion-function "ssh" '((tramp-parse-sconfig "/etc/ssh_config") (tramp-parse-sconfig "~/.ssh/config"))) @result{} ((tramp-parse-sconfig "/etc/ssh_config") (tramp-parse-sconfig "~/.ssh/config")) @end example @end defun The following predefined functions parsing configuration files exist: @table @asis @item @code{tramp-parse-rhosts} @findex tramp-parse-rhosts This function parses files which are syntactical equivalent to @file{~/.rhosts}. It returns both host names and user names, if specified. @item @code{tramp-parse-shosts} @findex tramp-parse-shosts This function parses files which are syntactical equivalent to @file{~/.ssh/known_hosts}. Since there are no user names specified in such files, it can return host names only. @item @code{tramp-parse-sconfig} @findex tramp-parse-shosts This function returns the host nicknames defined by @code{Host} entries in @file{~/.ssh/config} style files. @item @code{tramp-parse-shostkeys} @findex tramp-parse-shostkeys SSH2 parsing of directories @file{/etc/ssh2/hostkeys/*} and @file{~/ssh2/hostkeys/*}. Hosts are coded in file names @file{hostkey_@var{portnumber}_@var{host-name}.pub}. User names are always @code{nil}. @item @code{tramp-parse-sknownhosts} @findex tramp-parse-shostkeys Another SSH2 style parsing of directories like @file{/etc/ssh2/knownhosts/*} and @file{~/ssh2/knownhosts/*}. This case, hosts names are coded in file names @file{@var{host-name}.@var{algorithm}.pub}. User names are always @code{nil}. @item @code{tramp-parse-hosts} @findex tramp-parse-hosts A function dedicated to @file{/etc/hosts} style files. It returns host names only. @item @code{tramp-parse-passwd} @findex tramp-parse-passwd A function which parses @file{/etc/passwd} like files. Obviously, it can return user names only. @item @code{tramp-parse-netrc} @findex tramp-parse-netrc Finally, a function which parses @file{~/.netrc} like files. This includes also @file{~/.authinfo}-style files. @end table If you want to keep your own data in a file, with your own structure, you might provide such a function as well. This function must meet the following conventions: @defun my-tramp-parse file @var{file} must be either a file name on your host, or @code{nil}. The function must return a list of (@var{user} @var{host}), which are taken as candidates for user and host name completion. Example: @example (my-tramp-parse "~/.my-tramp-hosts") @result{} ((nil "toto") ("daniel" "melancholia")) @end example @end defun @node Password handling @section Reusing passwords for several connections @cindex passwords Sometimes it is necessary to connect to the same remote host several times. Reentering passwords again and again would be annoying, when the chosen method does not support access without password prompt through own configuration. The best recommendation is to use the method's own mechanism for password handling. Consider @command{ssh-agent} for @option{ssh}-like methods, or @command{pageant} for @option{plink}-like methods. However, if you cannot apply such native password handling, @value{tramp} offers alternatives. @anchor{Using an authentication file} @subsection Using an authentication file @vindex auth-sources The package @file{auth-source.el}, originally developed in No Gnus, offers the possibility to read passwords from a file, like FTP does it from @file{~/.netrc}. The default authentication file is @file{~/.authinfo.gpg}, this can be changed via the variable @code{auth-sources}. @noindent A typical entry in the authentication file would be @example machine melancholia port scp login daniel password geheim @end example The port can be any @value{tramp} method (@pxref{Inline methods}, @pxref{External methods}), to match only this method. When you omit the port, you match all @value{tramp} methods. In case of problems, setting @code{auth-source-debug} to @code{t} gives useful debug messages. @anchor{Caching passwords} @subsection Caching passwords If there is no authentication file, @value{tramp} caches the passwords entered by you. They will be reused next time if a connection needs them for the same user name and host name, independently of the connection method. @vindex password-cache-expiry Passwords are not saved permanently, that means the password caching is limited to the lifetime of your @value{emacsname} session. You can influence the lifetime of password caching by customizing the variable @code{password-cache-expiry}. The value is the number of seconds how long passwords are cached. Setting it to @code{nil} disables the expiration. @vindex password-cache If you don't like this feature for security reasons, password caching can be disabled totally by customizing the variable @code{password-cache} (setting it to @code{nil}). Implementation Note: password caching is based on the package @file{password-cache.el}. For the time being, it is activated only when this package is seen in the @code{load-path} while loading @value{tramp}. @ifset installchapter If you don't use No Gnus, you can take @file{password.el} from the @value{tramp} @file{contrib} directory, see @ref{Installation parameters}. @end ifset @node Connection caching @section Reusing connection related information @cindex caching @vindex tramp-persistency-file-name In order to reduce initial connection time, @value{tramp} stores connection related information persistently. The variable @code{tramp-persistency-file-name} keeps the file name where these information are written. Its default value is @ifset emacs @file{~/.emacs.d/tramp}. @end ifset @ifset xemacs @file{~/.xemacs/tramp}. @end ifset It is recommended to choose a local file name. @value{tramp} reads this file during startup, and writes it when exiting @value{emacsname}. You can simply remove this file if @value{tramp} shall be urged to recompute these information next @value{emacsname} startup time. Using such persistent information can be disabled by setting @code{tramp-persistency-file-name} to @code{nil}. Once consequence of reusing connection related information is that @var{tramp} needs to distinguish hosts. If you, for example, run a local @code{sshd} on port 3001, which tunnels @command{ssh} to another host, you could access both @file{@trampfn{ssh, , localhost,}} and @file{@trampfn{ssh, , localhost#3001,}}. @var{tramp} would use the same host related information (like paths, Perl variants, etc) for both connections, although the information is valid only for one of them. In order to avoid trouble, you must use another host name for one of the connections, like introducing a @option{Host} section in @file{~/.ssh/config} (@pxref{Frequently Asked Questions}) or applying multiple hops (@pxref{Multi-hops}). When @value{tramp} detects a changed operating system version on a remote host (via the command @command{uname -sr}), it flushes all connection related information for this host, and opens the connection again. @node Predefined connection information @section Setting own connection related information Sometimes, @var{tramp} is not able to detect correct connection related information. In such cases, you could tell @var{tramp} which value it has to take. Since this could result in errors, it has to be used with care. @vindex tramp-connection-properties Such settings can be performed via the list @code{tramp-connection-properties}. An entry in this list has the form @code{(@var{regexp} @var{property} @var{value})}. @var{regexp} matches remote file names for which a property shall be predefined. It can be @code{nil}. @var{property} is a string, and @var{value} the corresponding value. @var{property} could be any property found in the file @code{tramp-persistency-file-name}. A special property is @code{"busybox"}. This must be set, if the remote host runs a very restricted busybox as shell, which closes the connection at will. Since there is no reliable test for this, @var{tramp} must be indicated this way. Example: @lisp (add-to-list 'tramp-connection-properties (list (regexp-quote "@trampfn{ssh, user, randomhost.your.domain,}") "busybox" t)) @end lisp @node Remote Programs @section How @value{tramp} finds and uses programs on the remote machine @value{tramp} depends on a number of programs on the remote host in order to function, including @command{ls}, @command{test}, @command{find} and @command{cat}. In addition to these required tools, there are various tools that may be required based on the connection method. See @ref{Inline methods} and @ref{External methods} for details on these. Certain other tools, such as @command{perl} (or @command{perl5}) and @command{grep} will be used if they can be found. When they are available, they are used to improve the performance and accuracy of remote file access. @vindex tramp-remote-path @vindex tramp-default-remote-path @vindex tramp-own-remote-path @defopt tramp-remote-path When @value{tramp} connects to the remote machine, it searches for the programs that it can use. The variable @code{tramp-remote-path} controls the directories searched on the remote machine. By default, this is set to a reasonable set of defaults for most machines. The symbol @code{tramp-default-remote-path} is a place holder, it is replaced by the list of directories received via the command @command{getconf PATH} on your remote machine. For example, on Debian GNU/Linux this is @file{/bin:/usr/bin}, whereas on Solaris this is @file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin}. It is recommended to apply this symbol on top of @code{tramp-remote-path}. It is possible, however, that your local (or remote ;) system administrator has put the tools you want in some obscure local directory. In this case, you can still use them with @value{tramp}. You simply need to add code to your @file{.emacs} to add the directory to the remote path. This will then be searched by @value{tramp} when you connect and the software found. To add a directory to the remote search path, you could use code such as: @lisp @i{;; We load @value{tramp} to define the variable.} (require 'tramp) @i{;; We have @command{perl} in "/usr/local/perl/bin"} (add-to-list 'tramp-remote-path "/usr/local/perl/bin") @end lisp Another possibility is to reuse the path settings of your remote account when you log in. Usually, these settings are overwritten, because they might not be useful for @value{tramp}. The place holder @code{tramp-own-remote-path} preserves these settings. You can activate it via @lisp (add-to-list 'tramp-remote-path 'tramp-own-remote-path) @end lisp @end defopt @value{tramp} caches several information, like the Perl binary location. The changed remote search path wouldn't affect these settings. In order to force @value{tramp} to recompute these values, you must exit @value{emacsname}, remove your persistency file (@pxref{Connection caching}), and restart @value{emacsname}. @node Remote shell setup @section Remote shell setup hints @cindex remote shell setup @cindex @file{.profile} file @cindex @file{.login} file @cindex shell init files As explained in the @ref{Overview} section, @value{tramp} connects to the remote host and talks to the shell it finds there. Of course, when you log in, the shell executes its init files. Suppose your init file requires you to enter the birth date of your mother; clearly @value{tramp} does not know this and hence fails to log you in to that host. There are different possible strategies for pursuing this problem. One strategy is to enable @value{tramp} to deal with all possible situations. This is a losing battle, since it is not possible to deal with @emph{all} situations. The other strategy is to require you to set up the remote host such that it behaves like @value{tramp} expects. This might be inconvenient because you have to invest a lot of effort into shell setup before you can begin to use @value{tramp}. The package, therefore, pursues a combined approach. It tries to figure out some of the more common setups, and only requires you to avoid really exotic stuff. For example, it looks through a list of directories to find some programs on the remote host. And also, it knows that it is not obvious how to check whether a file exists, and therefore it tries different possibilities. (On some hosts and shells, the command @command{test -e} does the trick, on some hosts the shell builtin doesn't work but the program @command{/usr/bin/test -e} or @command{/bin/test -e} works. And on still other hosts, @command{ls -d} is the right way to do this.) Below you find a discussion of a few things that @value{tramp} does not deal with, and that you therefore have to set up correctly. @table @asis @item @var{shell-prompt-pattern} @vindex shell-prompt-pattern After logging in to the remote host, @value{tramp} has to wait for the remote shell startup to finish before it can send commands to the remote shell. The strategy here is to wait for the shell prompt. In order to recognize the shell prompt, the variable @code{shell-prompt-pattern} has to be set correctly to recognize the shell prompt on the remote host. Note that @value{tramp} requires the match for @code{shell-prompt-pattern} to be at the end of the buffer. Many people have something like the following as the value for the variable: @code{"^[^>$][>$] *"}. Now suppose your shell prompt is @code{a c $ }. In this case, @value{tramp} recognizes the @code{>} character as the end of the prompt, but it is not at the end of the buffer. @item @var{tramp-shell-prompt-pattern} @vindex tramp-shell-prompt-pattern This regular expression is used by @value{tramp} in the same way as @code{shell-prompt-pattern}, to match prompts from the remote shell. This second variable exists because the prompt from the remote shell might be different from the prompt from a local shell---after all, the whole point of @value{tramp} is to log in to remote hosts as a different user. The default value of @code{tramp-shell-prompt-pattern} is the same as the default value of @code{shell-prompt-pattern}, which is reported to work well in many circumstances. @item @var{tramp-password-prompt-regexp} @vindex tramp-password-prompt-regexp @vindex tramp-wrong-passwd-regexp During login, @value{tramp} might be forced to enter a password or a passphrase. The difference between both is that a password is requested from the shell on the remote host, while a passphrase is needed for accessing local authentication information, like your ssh key. @var{tramp-password-prompt-regexp} handles the detection of such requests for English environments. When you use another localization of your (local or remote) host, you might need to adapt this. Example: @lisp (setq tramp-password-prompt-regexp (concat "^.*" (regexp-opt '("passphrase" "Passphrase" ;; English "password" "Password" ;; Deutsch "passwort" "Passwort" ;; Fran@,{c}ais "mot de passe" "Mot de passe") t) ".*:\0? *")) @end lisp In parallel, it might also be necessary to adapt @var{tramp-wrong-passwd-regexp}. @item @command{tset} and other questions @cindex Unix command tset @cindex tset Unix command Some people invoke the @command{tset} program from their shell startup scripts which asks the user about the terminal type of the shell. Maybe some shells ask other questions when they are started. @value{tramp} does not know how to answer these questions. There are two approaches for dealing with this problem. One approach is to take care that the shell does not ask any questions when invoked from @value{tramp}. You can do this by checking the @env{TERM} environment variable, it will be set to @code{dumb} when connecting. @vindex tramp-terminal-type The variable @code{tramp-terminal-type} can be used to change this value to @code{dumb}. @vindex tramp-actions-before-shell The other approach is to teach @value{tramp} about these questions. See the variable @code{tramp-actions-before-shell}. Example: @lisp (defconst my-tramp-prompt-regexp (concat (regexp-opt '("Enter the birth date of your mother:") t) "\\s-*") "Regular expression matching my login prompt question.") (defun my-tramp-action (proc vec) "Enter \"19000101\" in order to give a correct answer." (save-window-excursion (with-current-buffer (tramp-get-connection-buffer vec) (tramp-message vec 6 "\n%s" (buffer-string)) (tramp-send-string vec "19000101")))) (add-to-list 'tramp-actions-before-shell '(my-tramp-prompt-regexp my-tramp-action)) @end lisp @item Environment variables named like users in @file{.profile} If you have a user named frumple and set the variable @env{FRUMPLE} in your shell environment, then this might cause trouble. Maybe rename the variable to @env{FRUMPLE_DIR} or the like. This weird effect was actually reported by a @value{tramp} user! @item Non-Bourne commands in @file{.profile} After logging in to the remote host, @value{tramp} issues the command @command{exec /bin/sh}. (Actually, the command is slightly different.) When @command{/bin/sh} is executed, it reads some init files, such as @file{~/.shrc} or @file{~/.profile}. Now, some people have a login shell which is not @code{/bin/sh} but a Bourne-ish shell such as bash or ksh. Some of these people might put their shell setup into the files @file{~/.shrc} or @file{~/.profile}. This way, it is possible for non-Bourne constructs to end up in those files. Then, @command{exec /bin/sh} might cause the Bourne shell to barf on those constructs. As an example, imagine somebody putting @command{export FOO=bar} into the file @file{~/.profile}. The standard Bourne shell does not understand this syntax and will emit a syntax error when it reaches this line. Another example is the tilde (@code{~}) character, say when adding @file{~/bin} to @env{PATH}. Many Bourne shells will not expand this character, and since there is usually no directory whose name consists of the single character tilde, strange things will happen. What can you do about this? Well, one possibility is to make sure that everything in @file{~/.shrc} and @file{~/.profile} on all remote hosts is Bourne-compatible. In the above example, instead of @command{export FOO=bar}, you might use @command{FOO=bar; export FOO} instead. The other possibility is to put your non-Bourne shell setup into some other files. For example, bash reads the file @file{~/.bash_profile} instead of @file{~/.profile}, if the former exists. So bash aficionados just rename their @file{~/.profile} to @file{~/.bash_profile} on all remote hosts, and Bob's your uncle. The @value{tramp} developers would like to circumvent this problem, so if you have an idea about it, please tell us. However, we are afraid it is not that simple: before saying @command{exec /bin/sh}, @value{tramp} does not know which kind of shell it might be talking to. It could be a Bourne-ish shell like ksh or bash, or it could be a csh derivative like tcsh, or it could be zsh, or even rc. If the shell is Bourne-ish already, then it might be prudent to omit the @command{exec /bin/sh} step. But how to find out if the shell is Bourne-ish? @item Interactive shell prompt @value{tramp} redefines the shell prompt in order to parse the shell's output robustly. When calling an interactive shell by @kbd{M-x shell}, this doesn't look nice. You can redefine the shell prompt by checking the environment variable @env{INSIDE_EMACS}, which is set by @value{tramp}, in your startup script @file{~/.emacs_SHELLNAME}. @env{SHELLNAME} might be the string @code{bash} or similar, in case of doubt you could set it the environment variable @env{ESHELL} in your @file{.emacs}: @lisp (setenv "ESHELL" "bash") @end lisp Your file @file{~/.emacs_SHELLNAME} could contain code like @example # Reset the prompt for remote Tramp shells. if [ "$@{INSIDE_EMACS/*tramp*/tramp@}" == "tramp" ] ; then PS1="[\u@@\h \w]$ " fi @end example @ifinfo @ifset emacs @xref{Interactive Shell, , , @value{emacsdir}}. @end ifset @end ifinfo @end table @node Android shell setup @section Android shell setup hints @cindex android shell setup Android devices use a restricted shell. They can be accessed via the @option{adb} method. However, this restricts the access to a USB connection, and it requires the installation of the Android SDK on the local machine. When an @command{sshd} process runs on the Android device, like provided by the @code{SSHDroid} app, any @option{ssh}-based method can be used. This requires some special settings. The default shell @code{/bin/sh} does not exist. Instead, you shall use just @code{sh}, which invokes the shell installed on the device. You can instruct @value{tramp} by this form: @lisp (add-to-list 'tramp-connection-properties (list (regexp-quote "192.168.0.26") "remote-shell" "sh")) @end lisp @noindent with @samp{192.168.0.26} being the IP address of your Android device (@pxref{Predefined connection information}). The user settings for the @env{PATH} environment variable must be preserved. It has also been reported, that the commands in @file{/system/xbin} are better suited than the ones in @file{/system/bin}. Add these setting: @lisp (add-to-list 'tramp-remote-path 'tramp-own-remote-path) (add-to-list 'tramp-remote-path "/system/xbin") @end lisp @noindent If the Android device is not @samp{rooted}, you must give the shell a writable directory for temporary files: @lisp (add-to-list 'tramp-remote-process-environment "TMPDIR=$HOME") @end lisp @noindent Now you shall be able to open a remote connection with @kbd{C-x C-f @trampfn{ssh, , 192.168.0.26#2222, }}, given that @command{sshd} listens on port @samp{2222}. It is also recommended to add a corresponding entry to your @file{~/.ssh/config} for that connection, like @example Host android HostName 192.168.0.26 User root Port 2222 @end example @noindent In this case, you must change the setting for the remote shell to @lisp (add-to-list 'tramp-connection-properties (list (regexp-quote "android") "remote-shell" "sh")) @end lisp @noindent You would open the connection with @kbd{C-x C-f @trampfn{ssh, , android, }} then. @node Auto-save and Backup @section Auto-save and Backup configuration @cindex auto-save @cindex backup @ifset emacs @vindex backup-directory-alist @end ifset @ifset xemacs @vindex bkup-backup-directory-info @end ifset Normally, @value{emacsname} writes backup files to the same directory as the original files, but this behavior can be changed via the variable @ifset emacs @code{backup-directory-alist}. @end ifset @ifset xemacs @code{bkup-backup-directory-info}. @end ifset In connection with @value{tramp}, this can have unexpected side effects. Suppose that you specify that all backups should go to the directory @file{~/.emacs.d/backups/}, and then you edit the file @file{@trampfn{su, root, localhost, /etc/secretfile}}. The effect is that the backup file will be owned by you and not by root, thus possibly enabling others to see it even if they were not intended to see it. When @ifset emacs @code{backup-directory-alist} @end ifset @ifset xemacs @code{bkup-backup-directory-info} @end ifset is @code{nil} (the default), such problems do not occur. Therefore, it is useful to set special values for @value{tramp} files. For example, the following statement effectively `turns off' the effect of @ifset emacs @code{backup-directory-alist} @end ifset @ifset xemacs @code{bkup-backup-directory-info} @end ifset for @value{tramp} files: @ifset emacs @lisp (add-to-list 'backup-directory-alist (cons tramp-file-name-regexp nil)) @end lisp @end ifset @ifset xemacs @lisp (require 'backup-dir) (add-to-list 'bkup-backup-directory-info (list tramp-file-name-regexp "")) @end lisp @end ifset @ifset emacs It is also possible to disable backups depending on the used method. The following code disables backups for the @option{su} and @option{sudo} methods: @lisp (setq backup-enable-predicate (lambda (name) (and (normal-backup-enable-predicate name) (not (let ((method (file-remote-p name 'method))) (when (stringp method) (member method '("su" "sudo")))))))) @end lisp @end ifset Another possibility is to use the @value{tramp} variable @ifset emacs @code{tramp-backup-directory-alist}. @end ifset @ifset xemacs @code{tramp-bkup-backup-directory-info}. @end ifset This variable has the same meaning like @ifset emacs @code{backup-directory-alist}. @end ifset @ifset xemacs @code{bkup-backup-directory-info}. @end ifset If a @value{tramp} file is backed up, and DIRECTORY is an absolute local file name, DIRECTORY is prepended with the @value{tramp} file name prefix of the file to be backed up. @noindent Example: @ifset emacs @lisp (add-to-list 'backup-directory-alist (cons "." "~/.emacs.d/backups/")) (setq tramp-backup-directory-alist backup-directory-alist) @end lisp @end ifset @ifset xemacs @lisp (require 'backup-dir) (add-to-list 'bkup-backup-directory-info (list "." "~/.emacs.d/backups/" 'full-path)) (setq tramp-bkup-backup-directory-info bkup-backup-directory-info) @end lisp @end ifset @noindent The backup file name of @file{@trampfn{su, root, localhost, /etc/secretfile}} would be @ifset emacs @file{@trampfn{su, root, localhost, ~/.emacs.d/backups/!su:root@@localhost:!etc!secretfile~}} @end ifset @ifset xemacs @file{@trampfn{su, root, localhost, ~/.emacs.d/backups/![su!root@@localhost]!etc!secretfile~}} @end ifset The same problem can happen with auto-saving files. @ifset emacs The variable @code{auto-save-file-name-transforms} keeps information, on which directory an auto-saved file should go. By default, it is initialized for @value{tramp} files to the local temporary directory. On some versions of @value{emacsname}, namely the version built for Debian GNU/Linux, the variable @code{auto-save-file-name-transforms} contains the directory where @value{emacsname} was built. A workaround is to manually set the variable to a sane value. If auto-saved files should go into the same directory as the original files, @code{auto-save-file-name-transforms} should be set to @code{nil}. Another possibility is to set the variable @code{tramp-auto-save-directory} to a proper value. @end ifset @ifset xemacs For this purpose you can set the variable @code{auto-save-directory} to a proper value. @end ifset @node Windows setup hints @section Issues with Cygwin ssh @cindex Cygwin, issues This section needs a lot of work! Please help. @cindex method sshx with Cygwin @cindex sshx method with Cygwin The recent Cygwin installation of @command{ssh} works only with a Cygwinized @value{emacsname}. You can check it by typing @kbd{M-x eshell}, and starting @kbd{ssh test.machine}. The problem is evident if you see a message like this: @example Pseudo-terminal will not be allocated because stdin is not a terminal. @end example Older @command{ssh} versions of Cygwin are told to cooperate with @value{tramp} selecting @option{sshx} as the connection method. You can find information about setting up Cygwin in their FAQ at @uref{http://cygwin.com/faq/}. @cindex method scpx with Cygwin @cindex scpx method with Cygwin If you wish to use the @option{scpx} connection method, then you might have the problem that @value{emacsname} calls @command{scp} with a Windows filename such as @code{c:/foo}. The Cygwin version of @command{scp} does not know about Windows filenames and interprets this as a remote filename on the host @code{c}. One possible workaround is to write a wrapper script for @option{scp} which converts the Windows filename to a Cygwinized filename. @cindex Cygwin and ssh-agent @cindex SSH_AUTH_SOCK and @value{emacsname} on Windows If you want to use either @option{ssh} based method on Windows, then you might encounter problems with @command{ssh-agent}. Using this program, you can avoid typing the pass-phrase every time you log in. However, if you start @value{emacsname} from a desktop shortcut, then the environment variable @env{SSH_AUTH_SOCK} is not set and so @value{emacsname} and thus @value{tramp} and thus @command{ssh} and @command{scp} started from @value{tramp} cannot communicate with @command{ssh-agent}. It works better to start @value{emacsname} from the shell. If anyone knows how to start @command{ssh-agent} under Windows in such a way that desktop shortcuts can profit, please holler. I don't really know anything at all about Windows@dots{} @node Usage @chapter Using @value{tramp} @cindex using @value{tramp} Once you have installed @value{tramp} it will operate fairly transparently. You will be able to access files on any remote machine that you can log in to as though they were local. Files are specified to @value{tramp} using a formalized syntax specifying the details of the system to connect to. This is similar to the syntax used by the @value{ftppackagename} package. @cindex type-ahead Something that might happen which surprises you is that @value{emacsname} remembers all your keystrokes, so if you see a password prompt from @value{emacsname}, say, and hit @kbd{@key{RET}} twice instead of once, then the second keystroke will be processed by @value{emacsname} after @value{tramp} has done its thing. Why, this type-ahead is normal behavior, you say. Right you are, but be aware that opening a remote file might take quite a while, maybe half a minute when a connection needs to be opened. Maybe after half a minute you have already forgotten that you hit that key! @menu * Filename Syntax:: @value{tramp} filename conventions. * Filename completion:: Filename completion. * Ad-hoc multi-hops:: Declaring multiple hops in the file name. * Remote processes:: Integration with other @value{emacsname} packages. * Cleanup remote connections:: Cleanup remote connections. @end menu @node Filename Syntax @section @value{tramp} filename conventions @cindex filename syntax @cindex filename examples To access the file @var{localname} on the remote machine @var{machine} you would specify the filename @file{@trampfn{, , machine, localname}}. This will connect to @var{machine} and transfer the file using the default method. @xref{Default Method}. Some examples of @value{tramp} filenames are shown below. @table @file @item @value{prefix}melancholia@value{postfix}.emacs Edit the file @file{.emacs} in your home directory on the machine @code{melancholia}. @item @value{prefix}melancholia.danann.net@value{postfix}.emacs This edits the same file, using the fully qualified domain name of the machine. @item @value{prefix}melancholia@value{postfix}~/.emacs This also edits the same file; the @file{~} is expanded to your home directory on the remote machine, just like it is locally. @item @value{prefix}melancholia@value{postfix}~daniel/.emacs This edits the file @file{.emacs} in the home directory of the user @code{daniel} on the machine @code{melancholia}. The @file{~} construct is expanded to the home directory of that user on the remote machine. @item @value{prefix}melancholia@value{postfix}/etc/squid.conf This edits the file @file{/etc/squid.conf} on the machine @code{melancholia}. @end table @var{machine} can also be an IPv4 or IPv6 address, like in @file{@trampfn{, , 127.0.0.1, .emacs}} or @file{@trampfn{, , @value{ipv6prefix}::1@value{ipv6postfix}, .emacs}}. @ifset emacs For syntactical reasons, IPv6 addresses must be embedded in square brackets @file{@value{ipv6prefix}} and @file{@value{ipv6postfix}}. @end ifset Unless you specify a different name to use, @value{tramp} will use the current local user name as the remote user name to log in with. If you need to log in as a different user, you can specify the user name as part of the filename. To log in to the remote machine as a specific user, you use the syntax @file{@trampfn{, user, machine, path/to.file}}. That means that connecting to @code{melancholia} as @code{daniel} and editing @file{.emacs} in your home directory you would specify @file{@trampfn{, daniel, melancholia, .emacs}}. It is also possible to specify other file transfer methods (@pxref{Inline methods}, @pxref{External methods}) as part of the filename. @ifset emacs This is done by putting the method before the user and host name, as in @file{@value{prefix}@var{method}@value{postfixhop}} (Note the trailing colon). @end ifset @ifset xemacs This is done by replacing the initial @file{@value{prefix}} with @file{@value{prefix}@value{postfixhop}}. (Note the trailing slash!). @end ifset The user, machine and file specification remain the same. So, to connect to the machine @code{melancholia} as @code{daniel}, using the @option{ssh} method to transfer files, and edit @file{.emacs} in my home directory I would specify the filename @file{@trampfn{ssh, daniel, melancholia, .emacs}}. @ifset emacs A remote filename containing a host name only, which is equal to a method name, is not allowed. If such a host name is used, it must always be preceded by an explicit method name, like @file{@value{prefix}ssh@value{postfixhop}ssh@value{postfix}}. @end ifset Finally, for some methods it is possible to specify a different port number than the default one, given by the method. This is specified by adding @file{#} to the host name, like in @file{@trampfn{ssh, daniel, melancholia#42, .emacs}}. @node Filename completion @section Filename completion @cindex filename completion Filename completion works with @value{tramp} for completion of method names, of user names and of machine names as well as for completion of file names on remote machines. @ifset emacs In order to enable this, partial completion must be activated in your @file{.emacs}. @ifinfo @xref{Completion Options, , , @value{emacsdir}}. @end ifinfo @end ifset If you, for example, type @kbd{C-x C-f @value{prefix}t @key{TAB}}, @value{tramp} might give you as result the choice for @example @c @multitable {@trampfn{telnet, , melancholia.danann.net,}} {@trampfn{telnet, , 192.168.0.1,}} @multitable @columnfractions .5 .5 @ifset emacs @item @value{prefixhop}telnet@value{postfixhop} @tab tmp/ @item @value{prefixhop}toto@value{postfix} @tab @end ifset @ifset xemacs @item @value{prefixhop}telnet@value{postfixhop} @tab @value{prefixhop}toto@value{postfix} @end ifset @end multitable @end example @samp{@value{prefixhop}telnet@value{postfixhop}} is a possible completion for the respective method, @ifset emacs @samp{tmp/} stands for the directory @file{/tmp} on your local machine, @end ifset and @samp{@value{prefixhop}toto@value{postfix}} might be a host @value{tramp} has detected in your @file{~/.ssh/known_hosts} file (given you're using default method @option{ssh}). If you go on to type @kbd{e @key{TAB}}, the minibuffer is completed to @samp{@value{prefix}telnet@value{postfixhop}}. Next @kbd{@key{TAB}} brings you all machine names @value{tramp} detects in your @file{/etc/hosts} file, let's say @example @multitable @columnfractions .5 .5 @c @multitable {@trampfn{telnet, , melancholia.danann.net,}} {@trampfn{telnet, , 192.168.0.1,}} @item @trampfn{telnet, , 127.0.0.1,} @tab @trampfn{telnet, , 192.168.0.1,} @item @trampfn{telnet, , @value{ipv6prefix}::1@value{ipv6postfix},} @tab @trampfn{telnet, , localhost,} @item @trampfn{telnet, , melancholia.danann.net,} @tab @trampfn{telnet, , melancholia,} @end multitable @end example Now you can choose the desired machine, and you can continue to complete file names on that machine. If the configuration files (@pxref{Customizing Completion}), which @value{tramp} uses for analysis of completion, offer user names, those user names will be taken into account as well. Remote machines which have been visited in the past and kept persistently (@pxref{Connection caching}) will be offered too. Once the remote machine identification is completed, it comes to filename completion on the remote host. This works pretty much like for files on the local host, with the exception that minibuffer killing via a double-slash works only on the filename part, except that filename part starts with @file{//}. @ifset emacs A triple-slash stands for the default behavior. @end ifset @ifinfo @xref{Minibuffer File, , , @value{emacsdir}}. @end ifinfo @noindent Example: @example @ifset emacs @kbd{C-x C-f @trampfn{telnet, , melancholia, /usr/local/bin//etc} @key{TAB}} @print{} @trampfn{telnet, , melancholia, /etc} @kbd{C-x C-f @trampfn{telnet, , melancholia, //etc} @key{TAB}} @print{} /etc @kbd{C-x C-f @trampfn{telnet, , melancholia, /usr/local/bin///etc} @key{TAB}} @print{} /etc @end ifset @ifset xemacs @kbd{C-x C-f @trampfn{telnet, , melancholia, /usr/local/bin//}} @print{} @trampfn{telnet, , melancholia, /} @kbd{C-x C-f @trampfn{telnet, , melancholia, //}} @print{} / @end ifset @end example A remote directory might have changed its contents out of @value{emacsname} control, for example by creation or deletion of files by other processes. Therefore, during filename completion, the remote directory contents are reread regularly in order to detect such changes, which would be invisible otherwise (@pxref{Connection caching}). @defopt tramp-completion-reread-directory-timeout This variable defines the number of seconds since last remote command before rereading a directory contents. A value of 0 would require an immediate reread during filename completion, @code{nil} means to use always cached values for the directory contents. @end defopt @node Ad-hoc multi-hops @section Declaring multiple hops in the file name @cindex multi-hop, ad-hoc @cindex proxy hosts, ad-hoc Multiple hops are configured with the variable @code{tramp-default-proxies-alist} (@pxref{Multi-hops}). However, sometimes it is desirable to reach a remote host immediately, without configuration changes. This can be reached by an ad-hoc specification of the proxies. A proxy looks like a remote file name specification without the local file name part. It is prepended to the target remote file name, separated by @samp{|}. As an example, a remote file on @samp{you@@remotehost}, passing the proxy @samp{bird@@bastion}, could be opened by @example @c @kbd{C-x C-f @trampfn{ssh@value{postfixhop}bird@@bastion|ssh, you, @c remotehost, /path}} @kbd{C-x C-f @value{prefix}ssh@value{postfixhop}bird@@bastion|ssh@value{postfixhop}you@@remotehost@value{postfix}/path} @end example Multiple hops can be cascaded, separating all proxies by @samp{|}. The proxies can also contain the patterns @code{%h} or @code{%u}. The ad-hoc definition is added on the fly to @code{tramp-default-proxies-alist}. Therefore, during the lifetime of the @value{emacsname} session it is not necessary to enter this ad-hoc specification, again. The remote file name @samp{@trampfn{ssh, you, remotehost, /path}} would be sufficient from now on. @vindex tramp-save-ad-hoc-proxies @defopt tramp-save-ad-hoc-proxies This customer option controls whether ad-hoc definitions are kept persistently in @code{tramp-default-proxies-alist}. That means, those definitions are available also for future @value{emacsname} sessions. @end defopt @node Remote processes @section Integration with other @value{emacsname} packages @cindex compile @cindex recompile @value{tramp} supports running processes on a remote host. This allows to exploit @value{emacsname} packages without modification for remote file names. It does not work for the @option{ftp} method. Association of a pty, as specified in @code{start-file-process}, is not supported. @code{process-file} and @code{start-file-process} work on the remote host when the variable @code{default-directory} is remote: @lisp (let ((default-directory "/ssh:remote.host:")) (start-file-process "grep" (get-buffer-create "*grep*") "/bin/sh" "-c" "grep -e tramp *")) @end lisp @ifset emacsgvfs If the remote host is mounted via GVFS (see @ref{GVFS based methods}), the remote filesystem is mounted locally. Therefore, there are no remote processes; all processes run still locally on your machine with an adapted @code{default-directory}. This section does not apply for such connection methods. @end ifset Remote processes are started when a corresponding command is executed from a buffer belonging to a remote file or directory. Up to now, the packages @file{compile.el} (commands like @code{compile} and @code{grep}) and @file{gud.el} (@code{gdb} or @code{perldb}) have been integrated. Integration of further packages is planned, any help for this is welcome! When your program is not found in the default search path @value{tramp} sets on the remote machine, you should either use an absolute path, or extend @code{tramp-remote-path} (see @ref{Remote Programs}): @lisp (add-to-list 'tramp-remote-path "~/bin") (add-to-list 'tramp-remote-path "/appli/pub/bin") @end lisp The environment for your program can be adapted by customizing @code{tramp-remote-process-environment}. This variable is a list of strings. It is structured like @code{process-environment}. Each element is a string of the form @code{"ENVVARNAME=VALUE"}. An entry @code{"ENVVARNAME="} disables the corresponding environment variable, which might have been set in your init file like @file{~/.profile}. @noindent Adding an entry can be performed via @code{add-to-list}: @lisp (add-to-list 'tramp-remote-process-environment "JAVA_HOME=/opt/java") @end lisp Changing or removing an existing entry is not encouraged. The default values are chosen for proper @value{tramp} work. Nevertheless, if for example a paranoid system administrator disallows changing the @env{HISTORY} environment variable, you can customize @code{tramp-remote-process-environment}, or you can apply the following code in your @file{.emacs}: @lisp (let ((process-environment tramp-remote-process-environment)) (setenv "HISTORY" nil) (setq tramp-remote-process-environment process-environment)) @end lisp If you use other @value{emacsname} packages which do not run out-of-the-box on a remote host, please let us know. We will try to integrate them as well. @xref{Bug Reports}. @subsection Running remote programs that create local X11 windows If you want to run a remote program, which shall connect the X11 server you are using with your local host, you can set the @env{DISPLAY} environment variable on the remote host: @lisp (add-to-list 'tramp-remote-process-environment (format "DISPLAY=%s" (getenv "DISPLAY"))) @end lisp @noindent @code{(getenv "DISPLAY")} shall return a string containing a host name, which can be interpreted on the remote host; otherwise you might use a fixed host name. Strings like @code{:0} cannot be used properly on the remote host. Another trick might be that you put @code{ForwardX11 yes} or @code{ForwardX11Trusted yes} to your @file{~/.ssh/config} file for that host. @subsection Running @code{shell} on a remote host @cindex shell Calling @kbd{M-x shell} in a buffer related to a remote host runs the local shell as defined in @option{shell-file-name}. This might be also a valid path name for a shell to be applied on the remote host, but it will fail at least when your local and remote hosts belong to different system types, like @samp{windows-nt} and @samp{gnu/linux}. You must set the variable @option{explicit-shell-file-name} to the shell path name on the remote host, in order to start that shell on the remote host. @ifset emacs Starting with Emacs 24 this won't be necessary, if you call @code{shell} interactively. You will be asked for the remote shell path, if you are on a remote buffer, and if @option{explicit-shell-file-name} is equal to @code{nil}. @end ifset @subsection Running @code{shell-command} on a remote host @cindex shell-command @code{shell-command} allows to execute commands in a shell, either synchronously, either asynchronously. This works also on remote hosts. Example: @example @kbd{C-x C-f @trampfn{sudo, , , } @key{RET}} @kbd{M-! tail -f /var/log/syslog.log & @key{RET}} @end example You will see the buffer @file{*Async Shell Command*}, containing the continuous output of the @command{tail} command. @ifset emacs A similar behaviour can be reached by @kbd{M-x auto-revert-tail-mode}, if available. @end ifset @subsection Running @code{eshell} on a remote host @cindex eshell @value{tramp} is integrated into @file{eshell.el}. That is, you can open an interactive shell on your remote host, and run commands there. After you have started @kbd{M-x eshell}, you could perform commands like this: @example @b{~ $} cd @trampfn{sudo, , , /etc} @key{RET} @b{@trampfn{sudo, root, host, /etc} $} hostname @key{RET} host @b{@trampfn{sudo, root, host, /etc} $} id @key{RET} uid=0(root) gid=0(root) groups=0(root) @b{@trampfn{sudo, root, host, /etc} $} find-file shadow @key{RET} # @b{@trampfn{sudo, root, host, /etc} $} @end example @ifset emacs Since @value{emacsname} 23.2, @code{eshell} has also an own implementation of the @code{su} and @code{sudo} commands. Both commands change the default directory of the @file{*eshell*} buffer to the value related to the user the command has switched to. This works even on remote hosts, adding silently a corresponding entry to the variable @code{tramp-default-proxies-alist} (@pxref{Multi-hops}): @example @b{~ $} cd @trampfn{ssh, user, remotehost, /etc} @key{RET} @b{@trampfn{ssh, user, remotehost, /etc} $} find-file shadow @key{RET} File is not readable: @trampfn{ssh, user, remotehost, /etc/shadow} @b{@trampfn{ssh, user, remotehost, /etc} $} sudo find-file shadow @key{RET} # @b{@trampfn{ssh, user, remotehost, /etc} $} su - @key{RET} @b{@trampfn{su, root, remotehost, /root} $} id @key{RET} uid=0(root) gid=0(root) groups=0(root) @b{@trampfn{su, root, remotehost, /root} $} @end example @end ifset @anchor{Running a debugger on a remote host} @subsection Running a debugger on a remote host @cindex gud @cindex gdb @cindex perldb @file{gud.el} offers an unified interface to several symbolic debuggers @ifset emacs @ifinfo (@ref{Debuggers, , , @value{emacsdir}}). @end ifinfo @end ifset With @value{tramp}, it is possible to debug programs on remote hosts. You can call @code{gdb} with a remote file name: @example @kbd{M-x gdb @key{RET}} @b{Run gdb (like this):} gdb --annotate=3 @trampfn{ssh, , host, ~/myprog} @key{RET} @end example The file name can also be relative to a remote default directory. Given you are in a buffer that belongs to the remote directory @trampfn{ssh, , host, /home/user}, you could call @example @kbd{M-x perldb @key{RET}} @b{Run perldb (like this):} perl -d myprog.pl @key{RET} @end example It is not possible to use just the absolute local part of a remote file name as program to debug, like @kbd{perl -d /home/user/myprog.pl}, though. Arguments of the program to be debugged are taken literally. That means, file names as arguments must be given as ordinary relative or absolute file names, without any remote specification. @subsection Running remote processes on Windows hosts @cindex winexe @cindex powershell With the help of the @command{winexe} it is possible tu run processes on a remote Windows host. @value{tramp} has implemented this for @code{process-file} and @code{start-file-process}. The variable @code{tramp-smb-winexe-program} must contain the file name of your local @command{winexe} command. On the remote host, Powershell V2.0 must be installed; it is used to run the remote process. In order to open a remote shell on the Windows host via @kbd{M-x shell}, you must set the variables @option{explicit-shell-file-name} and @option{explicit-*-args}. If you want, for example, run @command{cmd}, you must set: @lisp (setq explicit-shell-file-name "cmd" explicit-cmd-args '("/q")) @end lisp @noindent In case of running @command{powershell} as remote shell, the settings are @lisp (setq explicit-shell-file-name "powershell" explicit-powershell-args '("-file" "-")) @end lisp @node Cleanup remote connections @section Cleanup remote connections @cindex cleanup Sometimes it is useful to cleanup remote connections. The following commands support this. @deffn Command tramp-cleanup-connection vec This command flushes all connection related objects. @option{vec} is the internal representation of a remote connection. Called interactively, the command offers all active remote connections in the minibuffer as remote file name prefix like @file{@trampfn{method, user, host, }}. The cleanup includes password cache (@pxref{Password handling}), file cache, connection cache (@pxref{Connection caching}), connection buffers. @end deffn @deffn Command tramp-cleanup-this-connection This command flushes all objects of the current buffer's remote connection. The same objects are removed as in @code{tramp-cleanup-connection}. @end deffn @deffn Command tramp-cleanup-all-connections This command flushes objects for all active remote connections. The same objects are removed as in @code{tramp-cleanup-connection}. @end deffn @deffn Command tramp-cleanup-all-buffers Like in @code{tramp-cleanup-all-connections}, all remote connections are cleaned up. Additionally all buffers, which are related to a remote connection, are killed. @end deffn @node Bug Reports @chapter Reporting Bugs and Problems @cindex bug reports Bugs and problems with @value{tramp} are actively worked on by the development team. Feature requests and suggestions are also more than welcome. The @value{tramp} mailing list is a great place to get information on working with @value{tramp}, solving problems and general discussion and advice on topics relating to the package. It is moderated so non-subscribers can post but messages will be delayed, possibly up to 48 hours (or longer in case of holidays), until the moderator approves your message. The mailing list is at @email{tramp-devel@@gnu.org}. Messages sent to this address go to all the subscribers. This is @emph{not} the address to send subscription requests to. Subscribing to the list is performed via @uref{http://lists.gnu.org/mailman/listinfo/tramp-devel/, the @value{tramp} Mail Subscription Page}. @ifset emacs @ifset installchapter Before sending a bug report, you could check whether @value{tramp} works at all. Run the test suite on your local machine, @ref{Testing}. @end ifset @end ifset @findex tramp-bug To report a bug in @value{tramp}, you should execute @kbd{M-x tramp-bug}. This will automatically generate a buffer with the details of your system and @value{tramp} version. When submitting a bug report, please try to describe in excruciating detail the steps required to reproduce the problem, the setup of the remote machine and any special conditions that exist. You should also check that your problem is not described already in @xref{Frequently Asked Questions}. If you can identify a minimal test case that reproduces the problem, include that with your bug report. This will make it much easier for the development team to analyze and correct the problem. Sometimes, there might be also problems due to Tramp caches. Flush all caches before running the test, @ref{Cleanup remote connections}. Before reporting the bug, you should set the verbosity level to 6 (@pxref{Traces and Profiles, Traces}) in the @file{~/.emacs} file and repeat the bug. Then, include the contents of the @file{*tramp/foo*} and @file{*debug tramp/foo*} buffers in your bug report. A verbosity level greater than 6 will produce a very huge debug buffer, which is mostly not necessary for the analysis. Please be aware that, with a verbosity level of 6 or greater, the contents of files and directories will be included in the debug buffer. Passwords you've typed will never be included there. @node Frequently Asked Questions @chapter Frequently Asked Questions @cindex frequently asked questions @cindex FAQ @itemize @bullet @item Where can I get the latest @value{tramp}? @value{tramp} is available under the URL below. @noindent @uref{ftp://ftp.gnu.org/gnu/tramp/} @noindent There is also a Savannah project page. @noindent @uref{http://savannah.gnu.org/projects/tramp/} @item Which systems does it work on? The package has been used successfully on Emacs 22, Emacs 23, Emacs 24, XEmacs 21 (starting with 21.4), and SXEmacs 22. The package was intended to work on Unix, and it really expects a Unix-like system on the remote end (except the @option{smb} method), but some people seemed to have some success getting it to work on MS Windows XP/Vista/7 @value{emacsname}. @item How could I speed up @value{tramp}? In the backstage, @value{tramp} needs a lot of operations on the remote host. The time for transferring data from and to the remote host as well as the time needed to perform the operations there count. In order to speed up @value{tramp}, one could either try to avoid some of the operations, or one could try to improve their performance. Use an external method, like @option{scp}. Use caching. This is already enabled by default. Information about the remote host as well as the remote files are cached for reuse. The information about remote hosts is kept in the file specified in @code{tramp-persistency-file-name}. Keep this file. If you are confident that files on remote hosts are not changed out of @value{emacsname}' control, set @code{remote-file-name-inhibit-cache} to @code{nil}. Set also @code{tramp-completion-reread-directory-timeout} to @code{nil}, @ref{Filename completion}. Disable version control. If you access remote files which are not under version control, a lot of check operations can be avoided by disabling VC@. This can be achieved by @lisp (setq vc-ignore-dir-regexp (format "\\(%s\\)\\|\\(%s\\)" vc-ignore-dir-regexp tramp-file-name-regexp)) @end lisp Disable excessive traces. The default trace level of @value{tramp}, defined in the variable @code{tramp-verbose}, is 3. You should increase this level only temporarily, hunting bugs. @item @value{tramp} does not connect to the remote host When @value{tramp} does not connect to the remote host, there are three reasons heading the bug mailing list: @itemize @minus @item Unknown characters in the prompt @value{tramp} needs to recognize the prompt on the remote machine after execution any command. This is not possible when the prompt contains unknown characters like escape sequences for coloring. This should be avoided on the remote side. @xref{Remote shell setup}. for setting the regular expression detecting the prompt. You can check your settings after an unsuccessful connection by switching to the @value{tramp} connection buffer @file{*tramp/foo*}, setting the cursor at the top of the buffer, and applying the expression @example @kbd{M-: (re-search-forward (concat tramp-shell-prompt-pattern "$"))} @end example If it fails, or the cursor is not moved at the end of the buffer, your prompt is not recognized correctly. A special problem is the zsh, which uses left-hand side and right-hand side prompts in parallel. Therefore, it is necessary to disable the zsh line editor on the remote host. You shall add to @file{~/.zshrc} the following command: @example [ $TERM = "dumb" ] && unsetopt zle && PS1='$ ' @end example Furthermore it has been reported, that @value{tramp} (like sshfs, incidentally) doesn't work with WinSSHD due to strange prompt settings. @item Echoed characters after login When the remote machine opens an echoing shell, there might be control characters in the welcome message. @value{tramp} tries to suppress such echoes via the @command{stty -echo} command, but sometimes this command is not reached, because the echoed output has confused @value{tramp} already. In such situations it might be helpful to use the @option{sshx} or @option{scpx} methods, which allocate a pseudo tty. @xref{Inline methods}. @item @value{tramp} doesn't transfer strings with more than 500 characters correctly On some few systems, the implementation of @code{process-send-string} seems to be broken for longer strings. It is reported for HP-UX, FreeBSD and Tru64 Unix, for example. This case, you should customize the variable @code{tramp-chunksize} to 500. For a description how to determine whether this is necessary see the documentation of @code{tramp-chunksize}. Additionally, it will be useful to set @code{file-precious-flag} to @code{t} for @value{tramp} files. Then the file contents will be written into a temporary file first, which is checked for correct checksum. @ifinfo @pxref{Saving Buffers, , , elisp} @end ifinfo @lisp (add-hook 'find-file-hook (lambda () (when (file-remote-p default-directory) (set (make-local-variable 'file-precious-flag) t)))) @end lisp @end itemize @item @value{tramp} does not recognize hung @command{ssh} sessions When your network connection is down, @command{ssh} sessions might hang. @value{tramp} cannot detect it safely, because it still sees a running @command{ssh} process. Timeouts cannot be used as well, because it cannot be predicted how long a remote command will last, for example when copying very large files. Therefore, you must configure the @command{ssh} process to die in such a case. The following entry in @file{~/.ssh/config} would do the job: @example Host * ServerAliveInterval 5 @end example @item @value{tramp} does not use my @command{ssh} @code{ControlPath} Your @code{ControlPath} setting will be overwritten by @command{ssh} sessions initiated by @value{tramp}. This is because a master session, initiated outside @value{emacsname}, could be closed, which would stall all other @command{ssh} sessions for that host inside @value{emacsname}. Consequently, if you connect to a remote host via @value{tramp}, you might be prompted for a password again, even if you have established already an @command{ssh} connection to that host. Further @value{tramp} connections to that host, for example in order to run a process on that host, will reuse that initial @command{ssh} connection. If your @command{ssh} version supports the @code{ControlPersist} option, you could customize the variable @code{tramp-ssh-controlmaster-options} to use your @code{ControlPath}, for example: @lisp (setq tramp-ssh-controlmaster-options (concat "-o ControlPath=/tmp/ssh-ControlPath-%%r@@%%h:%%p " "-o ControlMaster=auto -o ControlPersist=yes")) @end lisp Note, that "%r", "%h" and "%p" must be encoded as "%%r", "%%h" and "%%p", respectively. These settings can be suppressed, if they are configured properly in your @file{~/.ssh/config}: @lisp (setq tramp-use-ssh-controlmaster-options nil) @end lisp @item File name completion does not work with @value{tramp} When you log in to the remote machine, do you see the output of @command{ls} in color? If so, this may be the cause of your problems. @command{ls} outputs @acronym{ANSI} escape sequences that your terminal emulator interprets to set the colors. These escape sequences will confuse @value{tramp} however. In your @file{.bashrc}, @file{.profile} or equivalent on the remote machine you probably have an alias configured that adds the option @option{--color=yes} or @option{--color=auto}. You should remove that alias and ensure that a new login @emph{does not} display the output of @command{ls} in color. If you still cannot use filename completion, report a bug to the @value{tramp} developers. @item File name completion does not work in large directories @value{tramp} uses globbing for some operations. (Globbing means to use the shell to expand wildcards such as `*.c'.) This might create long command lines, especially in directories with many files. Some shells choke on long command lines, or don't cope well with the globbing itself. If you have a large directory on the remote end, you may wish to execute a command like @samp{ls -d * ..?* > /dev/null} and see if it hangs. Note that you must first start the right shell, which might be @command{/bin/sh}, @command{ksh} or @command{bash}, depending on which of those supports tilde expansion. @item How can I get notified when @value{tramp} file transfers are complete? The following snippet can be put in your @file{~/.emacs} file. It makes @value{emacsname} beep after reading from or writing to the remote host. @lisp (defadvice tramp-handle-write-region (after tramp-write-beep-advice activate) "Make tramp beep after writing a file." (interactive) (beep)) (defadvice tramp-handle-do-copy-or-rename-file (after tramp-copy-beep-advice activate) "Make tramp beep after copying a file." (interactive) (beep)) (defadvice tramp-handle-insert-file-contents (after tramp-insert-beep-advice activate) "Make tramp beep after inserting a file." (interactive) (beep)) @end lisp @ifset emacs @item I'ld like to get a Visual Warning when working in a sudo:ed context When you are working with @samp{root} privileges, it might be useful to get an indication in the buffer's modeline. The following code, tested with @value{emacsname} 22.1, does the job. You should put it into your @file{~/.emacs}: @lisp (defun my-mode-line-function () (when (string-match "^/su\\(do\\)?:" default-directory) (setq mode-line-format (format-mode-line mode-line-format 'font-lock-warning-face)))) (add-hook 'find-file-hook 'my-mode-line-function) (add-hook 'dired-mode-hook 'my-mode-line-function) @end lisp @end ifset @ifset emacs @item I'ld like to see a host indication in the mode line when I'm remote The following code has been tested with @value{emacsname} 22.1. You should put it into your @file{~/.emacs}: @lisp (defconst my-mode-line-buffer-identification (list '(:eval (let ((host-name (if (file-remote-p default-directory) (tramp-file-name-host (tramp-dissect-file-name default-directory)) (system-name)))) (if (string-match "^[^0-9][^.]*\\(\\..*\\)" host-name) (substring host-name 0 (match-beginning 1)) host-name))) ": %12b")) (setq-default mode-line-buffer-identification my-mode-line-buffer-identification) (add-hook 'dired-mode-hook (lambda () (setq mode-line-buffer-identification my-mode-line-buffer-identification))) @end lisp Since @value{emacsname} 23.1, the mode line contains an indication if @code{default-directory} for the current buffer is on a remote host. The corresponding tooltip includes the name of that host. If you still want the host name as part of the mode line, you can use the example above, but the @code{:eval} clause can be simplified: @lisp '(:eval (let ((host-name (or (file-remote-p default-directory 'host) (system-name)))) (if (string-match "^[^0-9][^.]*\\(\\..*\\)" host-name) (substring host-name 0 (match-beginning 1)) host-name))) @end lisp @end ifset @ifset emacs @item My remote host does not understand default directory listing options @value{emacsname} computes the @command{dired} options depending on the local host you are working. If your @command{ls} command on the remote host does not understand those options, you can change them like this: @lisp (add-hook 'dired-before-readin-hook (lambda () (when (file-remote-p default-directory) (setq dired-actual-switches "-al")))) @end lisp @end ifset @item There's this @file{~/.sh_history} file on the remote host which keeps growing and growing. What's that? Sometimes, @value{tramp} starts @command{ksh} on the remote host for tilde expansion. Maybe @command{ksh} saves the history by default. @value{tramp} tries to turn off saving the history, but maybe you have to help. For example, you could put this in your @file{.kshrc}: @example if [ -f $HOME/.sh_history ] ; then /bin/rm $HOME/.sh_history fi if [ "$@{HISTFILE-unset@}" != "unset" ] ; then unset HISTFILE fi if [ "$@{HISTSIZE-unset@}" != "unset" ] ; then unset HISTSIZE fi @end example @item There are longish file names to type. How to shorten this? Let's say you need regularly access to @file{@trampfn{ssh, news, news.my.domain, /opt/news/etc}}, which is boring to type again and again. The following approaches can be mixed: @enumerate @item Use default values for method and user name: You can define default methods and user names for hosts, (@pxref{Default Method}, @pxref{Default User}): @lisp (setq tramp-default-method "ssh" tramp-default-user "news") @end lisp The file name left to type would be @kbd{C-x C-f @trampfn{, , news.my.domain, /opt/news/etc}}. Note that there are some useful settings already. Accessing your local host as @samp{root} user, is possible just by @kbd{C-x C-f @trampfn{su, , ,}}. @item Use configuration possibilities of your method: Several connection methods (i.e., the programs used) offer powerful configuration possibilities (@pxref{Customizing Completion}). In the given case, this could be @file{~/.ssh/config}: @example Host xy HostName news.my.domain User news @end example The file name left to type would be @kbd{C-x C-f @trampfn{ssh, , xy, /opt/news/etc}}. Depending on files in your directories, it is even possible to complete the host name with @kbd{C-x C-f @value{prefix}ssh@value{postfixhop}x @key{TAB}}. @item Use environment variables: File names typed in the minibuffer can be expanded by environment variables. You can set them outside @value{emacsname}, or even with Lisp: @lisp (setenv "xy" "@trampfn{ssh, news, news.my.domain, /opt/news/etc/}") @end lisp Then you need simply to type @kbd{C-x C-f $xy @key{RET}}, and here you are. The disadvantage is that you cannot edit the file name, because environment variables are not expanded during editing in the minibuffer. @item Define own keys: You can define your own key sequences in @value{emacsname}, which can be used instead of @kbd{C-x C-f}: @lisp (global-set-key [(control x) (control y)] (lambda () (interactive) (find-file (read-file-name "Find Tramp file: " "@trampfn{ssh, news, news.my.domain, /opt/news/etc/}")))) @end lisp Simply typing @kbd{C-x C-y} would initialize the minibuffer for editing with your beloved file name. See also @uref{http://www.emacswiki.org/cgi-bin/wiki/TrampMode, the Emacs Wiki} for a more comprehensive example. @item Define own abbreviation (1): It is possible to define an own abbreviation list for expanding file names: @lisp (add-to-list 'directory-abbrev-alist '("^/xy" . "@trampfn{ssh, news, news.my.domain, /opt/news/etc/}")) @end lisp This shortens the file opening command to @kbd{C-x C-f /xy @key{RET}}. The disadvantage is, again, that you cannot edit the file name, because the expansion happens after entering the file name only. @item Define own abbreviation (2): The @code{abbrev-mode} gives more flexibility for editing the minibuffer: @lisp (define-abbrev-table 'my-tramp-abbrev-table '(("xy" "@trampfn{ssh, news, news.my.domain, /opt/news/etc/}"))) (add-hook 'minibuffer-setup-hook (lambda () (abbrev-mode 1) (setq local-abbrev-table my-tramp-abbrev-table))) (defadvice minibuffer-complete (before my-minibuffer-complete activate) (expand-abbrev)) ;; If you use partial-completion-mode (defadvice PC-do-completion (before my-PC-do-completion activate) (expand-abbrev)) @end lisp After entering @kbd{C-x C-f xy @key{TAB}}, the minibuffer is expanded, and you can continue editing. @item Use bookmarks: Bookmarks can be used to visit Tramp files or directories. @ifinfo @pxref{Bookmarks, , , @value{emacsdir}} @end ifinfo When you have opened @file{@trampfn{ssh, news, news.my.domain, /opt/news/etc/}}, you should save the bookmark via @ifset emacs @kbd{@key{menu-bar} @key{edit} @key{bookmarks} @key{set}}. @end ifset @ifset xemacs @kbd{@key{menu-bar} @key{view} @key{bookmarks} @key{set}}. @end ifset Later on, you can always navigate to that bookmark via @ifset emacs @kbd{@key{menu-bar} @key{edit} @key{bookmarks} @key{jump}}. @end ifset @ifset xemacs @kbd{@key{menu-bar} @key{view} @key{bookmarks} @key{jump}}. @end ifset @item Use recent files: @ifset emacs @file{recentf} @end ifset @ifset xemacs @file{recent-files} @end ifset remembers visited places. @ifinfo @ifset emacs @pxref{File Conveniences, , , @value{emacsdir}} @end ifset @ifset xemacs @pxref{recent-files, , , edit-utils} @end ifset @end ifinfo You could keep remote file names in the recent list without checking their readability through a remote access: @lisp @ifset emacs (recentf-mode 1) @end ifset @ifset xemacs (recent-files-initialize) (add-hook 'find-file-hook (lambda () (when (file-remote-p (buffer-file-name)) (recent-files-make-permanent))) 'append) @end ifset @end lisp The list of files opened recently is reachable via @ifset emacs @kbd{@key{menu-bar} @key{file} @key{Open Recent}}. @end ifset @ifset xemacs @kbd{@key{menu-bar} @key{Recent Files}}. @end ifset @ifset emacs @item Use filecache: @file{filecache} remembers visited places. Add the directory into the cache: @lisp (eval-after-load "filecache" '(file-cache-add-directory "@trampfn{ssh, news, news.my.domain, /opt/news/etc/}")) @end lisp Whenever you want to load a file, you can enter @kbd{C-x C-f C-@key{TAB}} in the minibuffer. The completion is done for the given directory. @end ifset @ifset emacs @item Use bbdb: @file{bbdb} has a built-in feature for @value{ftppackagename} files, which works also for @value{tramp}. @ifinfo @pxref{bbdb-ftp, Storing FTP sites in the BBDB, , bbdb} @end ifinfo You need to load @file{bbdb}: @lisp (require 'bbdb) (bbdb-initialize) @end lisp Then you can create a BBDB entry via @kbd{M-x bbdb-create-ftp-site}. Because BBDB is not prepared for @value{tramp} syntax, you must specify a method together with the user name when needed. Example: @example @kbd{M-x bbdb-create-ftp-site @key{RET}} @b{Ftp Site:} news.my.domain @key{RET} @b{Ftp Directory:} /opt/news/etc/ @key{RET} @b{Ftp Username:} ssh@value{postfixhop}news @key{RET} @b{Company:} @key{RET} @b{Additional Comments:} @key{RET} @end example When you have opened your BBDB buffer, you can access such an entry by pressing the key @key{F}. @end ifset @end enumerate I would like to thank all @value{tramp} users who have contributed to the different recipes! @ifset emacs @item How can I use @value{tramp} to connect to a remote @value{emacsname} session? You can configure Emacs Client doing this. @ifinfo @xref{Emacs Server, , , @value{emacsdir}}. @end ifinfo On the remote host, you start the Emacs Server: @lisp (require 'server) (setq server-host (system-name) server-use-tcp t) (server-start) @end lisp Make sure that the result of @code{(system-name)} can be resolved on your local host; otherwise you might use a hard coded IP address. The resulting file @file{~/.emacs.d/server/server} must be copied to your local host, at the same location. You can call then the Emacs Client from the command line: @example emacsclient @trampfn{ssh, user, host, /file/to/edit} @end example @code{user} and @code{host} shall be related to your local host. If you want to use Emacs Client also as editor for other programs, you could write a script @file{emacsclient.sh}: @example #!/bin/sh emacsclient @trampfn{ssh, $(whoami), $(hostname --fqdn), $1} @end example Then you must set the environment variable @env{EDITOR} pointing to that script: @example export EDITOR=/path/to/emacsclient.sh @end example @end ifset @item There are packages which call @value{tramp} although I haven't entered a remote file name ever. I dislike it, how could I disable it? In general, @value{tramp} functions are used only when you apply remote file name syntax. However, some packages enable @value{tramp} on their own. @itemize @minus @item @file{ido.el} You could disable @value{tramp} file name completion: @lisp (custom-set-variables '(ido-enable-tramp-completion nil)) @end lisp @item @file{rlogin.el} You could disable remote directory tracking mode: @lisp (rlogin-directory-tracking-mode -1) @end lisp @end itemize @item How can I disable @value{tramp} at all? Shame on you, why did you read until now? @itemize @minus @ifset emacs @item If you just want to have @value{ftppackagename} as default remote files access package, you should apply the following code: @lisp (setq tramp-default-method "ftp") @end lisp @end ifset @item In order to disable @ifset emacs @value{tramp} (and @value{ftppackagename}), @end ifset @ifset xemacs @value{tramp}, @end ifset you must set @code{tramp-mode} to @code{nil}: @lisp (setq tramp-mode nil) @end lisp @item Unloading @value{tramp} can be achieved by applying @kbd{M-x tramp-unload-tramp}. @ifset emacs This resets also the @value{ftppackagename} plugins. @end ifset @end itemize @end itemize @c For the developer @node Files directories and localnames @chapter How file names, directories and localnames are mangled and managed. @menu * Localname deconstruction:: Breaking a localname into its components. @ifset emacs * External packages:: Integration with external Lisp packages. @end ifset @end menu @node Localname deconstruction @section Breaking a localname into its components @value{tramp} file names are somewhat different, obviously, to ordinary file names. As such, the lisp functions @code{file-name-directory} and @code{file-name-nondirectory} are overridden within the @value{tramp} package. Their replacements are reasonably simplistic in their approach. They dissect the filename, call the original handler on the localname and then rebuild the @value{tramp} file name with the result. This allows the platform specific hacks in the original handlers to take effect while preserving the @value{tramp} file name information. @ifset emacs @node External packages @section Integration with external Lisp packages @subsection Filename completion. While reading filenames in the minibuffer, @value{tramp} must decide whether it completes possible incomplete filenames, or not. Imagine there is the following situation: You have typed @kbd{C-x C-f @value{prefix}ssh@value{postfixhop} @key{TAB}}. @value{tramp} cannot know, whether @option{ssh} is a method or a host name. It checks therefore the last input character you have typed. If this is @key{TAB}, @key{SPACE} or @kbd{?}, @value{tramp} assumes that you are still in filename completion, and it does not connect to the possible remote host @option{ssh}. External packages, which use other characters for completing filenames in the minibuffer, must signal this to @value{tramp}. For this case, the variable @code{non-essential} can be bound temporarily to a non-@code{nil} value. @lisp (let ((non-essential t)) ...) @end lisp @subsection File attributes cache. When @value{tramp} runs remote processes, files on the remote host could change their attributes. Consequently, @value{tramp} must flush its complete cache keeping attributes for all files of the remote host it has seen so far. This is a performance degradation, because the lost file attributes must be recomputed when needed again. In cases the caller of @code{process-file} knows that there are no file attribute changes, it shall let-bind the variable @code{process-file-side-effects} to @code{nil}. @value{tramp} wouldn't flush the file attributes cache then. @lisp (let (process-file-side-effects) ...) @end lisp For asynchronous processes, @value{tramp} flushes the file attributes cache via a process sentinel. If the caller of @code{start-file-process} knows that there are no file attribute changes, it shall set the process sentinel to @code{nil}. In case the caller defines an own process sentinel, @value{tramp}'s process sentinel is overwritten. The caller can still flush the file attributes cache in its process sentinel with this code: @lisp (unless (memq (process-status proc) '(run open)) (dired-uncache remote-directory)) @end lisp @code{remote-directory} shall be the root directory, where file attribute changes can happen during the process lifetime. @value{tramp} traverses all subdirectories, starting at this directory. Often, it is sufficient to use @code{default-directory} of the process buffer as root directory. @end ifset @node Traces and Profiles @chapter How to Customize Traces All @value{tramp} messages are raised with a verbosity level. The verbosity level can be any number between 0 and 10. Only messages with a verbosity level less than or equal to @code{tramp-verbose} are displayed. The verbosity levels are @w{ 0} silent (no @value{tramp} messages at all) @*@indent @w{ 1} errors @*@indent @w{ 2} warnings @*@indent @w{ 3} connection to remote hosts (default verbosity) @*@indent @w{ 4} activities @*@indent @w{ 5} internal @*@indent @w{ 6} sent and received strings @*@indent @w{ 7} file caching @*@indent @w{ 8} connection properties @*@indent @w{ 9} test commands @*@indent @w{10} traces (huge) When @code{tramp-verbose} is greater than or equal to 4, the messages are also written into a @value{tramp} debug buffer. This debug buffer is useful for analyzing problems; sending a @value{tramp} bug report should be done with @code{tramp-verbose} set to a verbosity level of at least 6 (@pxref{Bug Reports}). The debug buffer is in @ifinfo @ref{Outline Mode, , , @value{emacsdir}}. @end ifinfo @ifnotinfo Outline Mode. @end ifnotinfo That means, you can change the level of messages to be viewed. If you want, for example, see only messages up to verbosity level 5, you must enter @kbd{C-u 6 C-c C-q}. @ifinfo Other keys for navigating are described in @ref{Outline Visibility, , , @value{emacsdir}}. @end ifinfo @value{tramp} errors are handled internally in order to raise the verbosity level 1 messages. When you want to get a Lisp backtrace in case of an error, you need to set both @lisp (setq debug-on-error t debug-on-signal t) @end lisp Sometimes, it might be even necessary to step through @value{tramp} function call traces. Such traces are enabled by the following code: @lisp (require 'tramp) (require 'trace) (dolist (elt (all-completions "tramp-" obarray 'functionp)) (trace-function-background (intern elt))) (untrace-function 'tramp-read-passwd) (untrace-function 'tramp-gw-basic-authentication) @end lisp The function call traces are inserted in the buffer @file{*trace-output*}. @code{tramp-read-passwd} and @code{tramp-gw-basic-authentication} shall be disabled when the function call traces are added to @value{tramp}, because both functions return password strings, which should not be distributed. @node Issues @chapter Debatable Issues and What Was Decided @itemize @bullet @item The uuencode method does not always work. Due to the design of @value{tramp}, the encoding and decoding programs need to read from stdin and write to stdout. On some systems, @command{uudecode -o -} will read stdin and write the decoded file to stdout, on other systems @command{uudecode -p} does the same thing. But some systems have uudecode implementations which cannot do this at all---it is not possible to call these uudecode implementations with suitable parameters so that they write to stdout. Of course, this could be circumvented: the @code{begin foo 644} line could be rewritten to put in some temporary file name, then @command{uudecode} could be called, then the temp file could be printed and deleted. But I have decided that this is too fragile to reliably work, so on some systems you'll have to do without the uuencode methods. @item The @value{tramp} filename syntax differs between Emacs and XEmacs. The Emacs maintainers wish to use a unified filename syntax for Ange-FTP and @value{tramp} so that users don't have to learn a new syntax. It is sufficient to learn some extensions to the old syntax. For the XEmacs maintainers, the problems caused from using a unified filename syntax are greater than the gains. The XEmacs package system uses EFS for downloading new packages. So, obviously, EFS has to be installed from the start. If the filenames were unified, @value{tramp} would have to be installed from the start, too. @ifset xemacs @strong{Note:} If you'd like to use a similar syntax like @value{ftppackagename}, you need the following settings in your init file: @lisp (setq tramp-unified-filenames t) (require 'tramp) @end lisp The autoload of the @value{emacsname} @value{tramp} package must be disabled. This can be achieved by setting file permissions @code{000} to the files @file{.../xemacs-packages/lisp/tramp/auto-autoloads.el*}. In case of unified filenames, all @value{emacsname} download sites are added to @code{tramp-default-method-alist} with default method @option{ftp} @xref{Default Method}. These settings shouldn't be touched for proper working of the @value{emacsname} package system. The syntax for unified filenames is described in the @value{tramp} manual for @value{emacsothername}. @end ifset @end itemize @node GNU Free Documentation License @appendix GNU Free Documentation License @include doclicense.texi @node Function Index @unnumbered Function Index @printindex fn @node Variable Index @unnumbered Variable Index @printindex vr @node Concept Index @unnumbered Concept Index @printindex cp @bye @c TODO @c @c * Say something about the .login and .profile files of the remote @c shells. @c * Explain how tramp.el works in principle: open a shell on a remote @c host and then send commands to it. @c * Use `filename' resp. `file name' consistently. @c * Use `host' resp. `machine' consistently. @c * Consistent small or capitalized words especially in menus. @c * Make a unique declaration of @trampfn.