1 \input texinfo @c -*-texinfo-*-
2 @setfilename ../../info/tramp
4 @settitle TRAMP User Manual
7 @c This is *so* much nicer :)
10 @c In the Tramp CVS, the version number is auto-frobbed from
11 @c configure.ac, so you should edit that file and run
12 @c "autoconf && ./configure" to change the version number.
14 @c Additionally, flags are set with respect to the Emacs flavor; and
15 @c depending whether Tramp is packaged into (X)Emacs, or standalone.
17 @include trampver.texi
19 @c Macro for formatting a filename according to the respective syntax.
20 @c xxx and yyy are auxiliary macros in order to omit leading and
21 @c trailing whitespace. Not very elegant, but I don't know it better.
27 @macro yyy {one, two}@c
35 @macro trampfn {method, user, host, localname}@c
36 @value{prefix}@yyy{\method\,@value{postfixhop}}@yyy{\user\,@@}\host\@value{postfix}\localname\@c
40 Copyright @copyright{} 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
41 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
44 Permission is granted to copy, distribute and/or modify this document
45 under the terms of the GNU Free Documentation License, Version 1.3 or
46 any later version published by the Free Software Foundation; with no
47 Invariant Sections, with the Front-Cover texts being ``A GNU Manual'',
48 and with the Back-Cover Texts as in (a) below. A copy of the license
49 is included in the section entitled ``GNU Free Documentation License''.
51 (a) The FSF's Back-Cover Text is: ``You have the freedom to
52 copy and modify this GNU manual. Buying copies from the FSF
53 supports it in developing GNU and promoting software freedom.''
57 @c Entries for @command{install-info} to use
58 @dircategory @value{emacsname} network features
60 * TRAMP: (tramp). Transparent Remote Access, Multiple Protocol
61 @value{emacsname} remote file access via rsh and rcp.
65 @title @value{tramp} version @value{trampver} User Manual
66 @author by Daniel Pittman
67 @author based on documentation by Kai Gro@ss{}johann
75 @node Top, Overview, (dir), (dir)
76 @top @value{tramp} version @value{trampver} User Manual
78 This file documents @value{tramp} version @value{trampver}, a remote file
79 editing package for @value{emacsname}.
81 @value{tramp} stands for `Transparent Remote (file) Access, Multiple
82 Protocol'. This package provides remote file editing, similar to
83 @value{ftppackagename}.
85 The difference is that @value{ftppackagename} uses FTP to transfer
86 files between the local and the remote host, whereas @value{tramp} uses a
87 combination of @command{rsh} and @command{rcp} or other work-alike
88 programs, such as @command{ssh}/@command{scp}.
90 You can find the latest version of this document on the web at
91 @uref{http://www.gnu.org/software/tramp/}.
93 @c Pointer to the other Emacs flavor is necessary only in case of
94 @c standalone installation.
96 The manual has been generated for @value{emacsname}.
98 If you want to read the info pages for @value{emacsothername}, you
99 should read in @ref{Installation} how to create them.
102 If you're using the other Emacs flavor, you should read the
103 @uref{@value{emacsotherfilename}, @value{emacsothername}} pages.
109 This manual is also available as a @uref{@value{japanesemanual},
110 Japanese translation}.
113 The latest release of @value{tramp} is available for
114 @uref{ftp://ftp.gnu.org/gnu/tramp/, download}, or you may see
115 @ref{Obtaining Tramp} for more details, including the CVS server
118 @value{tramp} also has a @uref{http://savannah.gnu.org/projects/tramp/,
119 Savannah Project Page}.
122 There is a mailing list for @value{tramp}, available at
123 @email{tramp-devel@@gnu.org}, and archived at
124 @uref{http://lists.gnu.org/archive/html/tramp-devel/, the
125 @value{tramp} Mail Archive}.
127 Older archives are located at
128 @uref{http://sourceforge.net/mailarchive/forum.php?forum=tramp-devel,
129 SourceForge Mail Archive} and
130 @uref{http://www.mail-archive.com/emacs-rcp@@ls6.cs.uni-dortmund.de/,
132 @c in HTML output, there's no new paragraph.
141 * Overview:: What @value{tramp} can and cannot do.
145 * Obtaining Tramp:: How to obtain @value{tramp}.
146 * History:: History of @value{tramp}.
147 @ifset installchapter
148 * Installation:: Installing @value{tramp} with your @value{emacsname}.
150 * Configuration:: Configuring @value{tramp} for use.
151 * Usage:: An overview of the operation of @value{tramp}.
152 * Bug Reports:: Reporting Bugs and Problems.
153 * Frequently Asked Questions:: Questions and answers from the mailing list.
154 * Function Index:: @value{tramp} functions.
155 * Variable Index:: User options and variables.
156 * Concept Index:: An item for each concept.
160 * Files directories and localnames:: How file names, directories and localnames are mangled and managed.
161 * Traces and Profiles:: How to Customize Traces.
162 * Issues:: Debatable Issues and What Was Decided.
164 * GNU Free Documentation License:: The license for this documentation.
167 --- The Detailed Node Listing ---
169 @ifset installchapter
170 Installing @value{tramp} with your @value{emacsname}
172 * Installation parameters:: Parameters in order to control installation.
173 * Load paths:: How to plug-in @value{tramp} into your environment.
174 * Japanese manual:: Japanese manual.
178 Configuring @value{tramp} for use
180 * Connection types:: Types of connections made to remote machines.
181 * Inline methods:: Inline methods.
182 * External methods:: External methods.
184 * GVFS based methods:: GVFS based external methods.
187 * Gateway methods:: Gateway methods.
189 * Default Method:: Selecting a default method.
190 * Default User:: Selecting a default user.
191 * Default Host:: Selecting a default host.
192 * Multi-hops:: Connecting to a remote host using multiple hops.
193 * Customizing Methods:: Using Non-Standard Methods.
194 * Customizing Completion:: Selecting config files for user/host name completion.
195 * Password handling:: Reusing passwords for several connections.
196 * Connection caching:: Reusing connection related information.
197 * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine.
198 * Remote shell setup:: Remote shell setup hints.
199 * Windows setup hints:: Issues with Cygwin ssh.
200 * Auto-save and Backup:: Auto-save and Backup.
204 * Filename Syntax:: @value{tramp} filename conventions.
205 * Alternative Syntax:: URL-like filename syntax.
206 * Filename completion:: Filename completion.
207 * Remote processes:: Integration with other @value{emacsname} packages.
208 * Cleanup remote connections:: Cleanup remote connections.
210 How file names, directories and localnames are mangled and managed
212 * Localname deconstruction:: Breaking a localname into its components.
214 * External packages:: Integration with external Lisp packages.
221 @chapter An overview of @value{tramp}
224 After the installation of @value{tramp} into your @value{emacsname}, you
225 will be able to access files on remote machines as though they were
226 local. Access to the remote file system for editing files, version
227 control, and @code{dired} are transparently enabled.
229 Your access to the remote machine can be with the @command{rsh},
230 @command{rlogin}, @command{telnet} programs or with any similar
231 connection method. This connection must pass @acronym{ASCII}
232 successfully to be usable but need not be 8-bit clean.
234 The package provides support for @command{ssh} connections out of the
235 box, one of the more common uses of the package. This allows
236 relatively secure access to machines, especially if @command{ftp}
239 Under Windows, @value{tramp} is integrated with the PuTTY package,
240 using the @command{plink} program.
242 The majority of activity carried out by @value{tramp} requires only that
243 the remote login is possible and is carried out at the terminal. In
244 order to access remote files @value{tramp} needs to transfer their content
245 to the local machine temporarily.
247 @value{tramp} can transfer files between the machines in a variety of ways.
248 The details are easy to select, depending on your needs and the
249 machines in question.
251 The fastest transfer methods for large files rely on a remote file
252 transfer package such as @command{rcp}, @command{scp}, @command{rsync}
253 or (under Windows) @command{pscp}.
255 If the remote copy methods are not suitable for you, @value{tramp} also
256 supports the use of encoded transfers directly through the shell.
257 This requires that the @command{mimencode} or @command{uuencode} tools
258 are available on the remote machine. These methods are generally
259 faster for small files.
261 @value{tramp} is still under active development and any problems you encounter,
262 trivial or major, should be reported to the @value{tramp} developers.
266 @subsubheading Behind the scenes
267 @cindex behind the scenes
268 @cindex details of operation
271 This section tries to explain what goes on behind the scenes when you
272 access a remote file through @value{tramp}.
274 Suppose you type @kbd{C-x C-f} and enter part of an @value{tramp} file name,
275 then hit @kbd{@key{TAB}} for completion. Suppose further that this is
276 the first time that @value{tramp} is invoked for the host in question. Here's
281 @value{tramp} discovers that it needs a connection to the host. So it
282 invokes @samp{telnet @var{host}} or @samp{rsh @var{host} -l
283 @var{user}} or a similar tool to connect to the remote host.
284 Communication with this process happens through an
285 @value{emacsname} buffer, that is, the output from the remote end
289 The remote host may prompt for a login name (for @command{telnet}).
290 The login name is given in the file name, so @value{tramp} sends the
291 login name and a newline.
294 The remote host may prompt for a password or pass phrase (for
295 @command{rsh} or for @command{telnet} after sending the login name).
296 @value{tramp} displays the prompt in the minibuffer, asking you for the
297 password or pass phrase.
299 You enter the password or pass phrase. @value{tramp} sends it to the remote
300 host, followed by a newline.
303 @value{tramp} now waits for the shell prompt or for a message that the login
306 If @value{tramp} sees neither of them after a certain period of time
307 (a minute, say), then it issues an error message saying that it
308 couldn't find the remote shell prompt and shows you what the remote
311 If @value{tramp} sees a @samp{login failed} message, it tells you so,
312 aborts the login attempt and allows you to try again.
315 Suppose that the login was successful and @value{tramp} sees the shell prompt
316 from the remote host. Now @value{tramp} invokes @command{/bin/sh} because
317 Bourne shells and C shells have different command
318 syntaxes.@footnote{Invoking @command{/bin/sh} will fail if your login
319 shell doesn't recognize @samp{exec /bin/sh} as a valid command.
320 Maybe you use the Scheme shell @command{scsh}@dots{}}
322 After the Bourne shell has come up, @value{tramp} sends a few commands to
323 ensure a good working environment. It turns off echoing, it sets the
324 shell prompt, and a few other things.
327 Now the remote shell is up and it good working order. Remember, what
328 was supposed to happen is that @value{tramp} tries to find out what files exist
329 on the remote host so that it can do filename completion.
331 So, @value{tramp} basically issues @command{cd} and @command{ls} commands and
332 also sometimes @command{echo} with globbing. Another command that is
333 often used is @command{test} to find out whether a file is writable or a
334 directory or the like. The output of each command is parsed for the
338 Suppose you are finished with filename completion, have entered @kbd{C-x
339 C-f}, a full file name and hit @kbd{@key{RET}}. Now comes the time to
340 transfer the file contents from the remote host to the local host so
341 that you can edit them.
343 See above for an explanation of how @value{tramp} transfers the file contents.
345 For inline transfers, @value{tramp} issues a command like @samp{mimencode -b
346 /path/to/remote/file}, waits until the output has accumulated in the
347 buffer that's used for communication, then decodes that output to
348 produce the file contents.
350 For external transfers, @value{tramp} issues a command like the
353 rcp user@@host:/path/to/remote/file /tmp/tramp.4711
355 It then reads the local temporary file @file{/tmp/tramp.4711} into a
356 buffer and deletes the temporary file.
359 You now edit the buffer contents, blithely unaware of what has happened
360 behind the scenes. (Unless you have read this section, that is.) When
361 you are finished, you type @kbd{C-x C-s} to save the buffer.
364 Again, @value{tramp} transfers the file contents to the remote host
365 either inline or external. This is the reverse of what happens when
369 I hope this has provided you with a basic overview of what happens
370 behind the scenes when you open a file with @value{tramp}.
374 @node Obtaining Tramp
375 @chapter Obtaining Tramp.
376 @cindex obtaining Tramp
378 @value{tramp} is freely available on the Internet and the latest
379 release may be downloaded from @uref{ftp://ftp.gnu.org/gnu/tramp/}.
380 This release includes the full documentation and code for
381 @value{tramp}, suitable for installation. But Emacs (22 or later)
382 includes @value{tramp} already, and there is a @value{tramp} package
383 for XEmacs, as well. So maybe it is easier to just use those. But if
384 you want the bleeding edge, read on@dots{...}
386 For the especially brave, @value{tramp} is available from CVS. The CVS
387 version is the latest version of the code and may contain incomplete
388 features or new issues. Use these versions at your own risk.
390 Instructions for obtaining the latest development version of @value{tramp}
391 from CVS can be found by going to the Savannah project page at the
392 following URL and then clicking on the CVS link in the navigation bar
396 @uref{http://savannah.gnu.org/projects/tramp/}
399 Or follow the example session below:
402 ] @strong{cd ~/@value{emacsdir}}
403 ] @strong{export CVS_RSH="ssh"}
404 ] @strong{cvs -z3 -d:pserver:anonymous@@cvs.savannah.gnu.org:/sources/tramp co tramp}
408 You should now have a directory @file{~/@value{emacsdir}/tramp}
409 containing the latest version of @value{tramp}. You can fetch the latest
410 updates from the repository by issuing the command:
413 ] @strong{cd ~/@value{emacsdir}/tramp}
414 ] @strong{export CVS_RSH="ssh"}
415 ] @strong{cvs update -d}
419 Once you've got updated files from the CVS repository, you need to run
420 @command{autoconf} in order to get an up-to-date @file{configure}
424 ] @strong{cd ~/@value{emacsdir}/tramp}
430 @chapter History of @value{tramp}
432 @cindex development history
434 Development was started end of November 1998. The package was called
435 @file{rssh.el}, back then. It only provided one method to access a
436 file, using @command{ssh} to log in to a remote host and using
437 @command{scp} to transfer the file contents. After a while, the name
438 was changed to @file{rcp.el}, and now it's @value{tramp}. Along the way,
439 many more methods for getting a remote shell and for transferring the
440 file contents were added. Support for VC was added.
442 After that, there were added the multi-hop methods in April 2000 and
443 the unification of @value{tramp} and Ange-FTP filenames in July 2002.
444 In July 2004, multi-hop methods have been replaced by proxy hosts.
445 Running commands on remote hosts was introduced in December 2005.
447 Support of gateways exists since April 2007.
450 GVFS integration started in February 2009.
453 Storing files into IMAP mailboxes has been added in September 2009.
456 In December 2001, @value{tramp} has been added to the XEmacs package
457 repository. Being part of the Emacs repository happened in June 2002,
458 the first release including @value{tramp} was Emacs 22.1.
460 @value{tramp} is also a Debian GNU/Linux package since February 2001.
463 @c Installation chapter is necessary only in case of standalone
464 @c installation. Text taken from trampinst.texi.
465 @ifset installchapter
466 @include trampinst.texi
470 @chapter Configuring @value{tramp} for use
471 @cindex configuration
473 @cindex default configuration
474 @value{tramp} is (normally) fully functional when it is initially
475 installed. It is initially configured to use the @command{scp}
476 program to connect to the remote host. So in the easiest case, you
477 just type @kbd{C-x C-f} and then enter the filename
478 @file{@trampfn{, user, machine, /path/to.file}}.
480 On some hosts, there are problems with opening a connection. These are
481 related to the behavior of the remote shell. See @xref{Remote shell
482 setup}, for details on this.
484 If you do not wish to use these commands to connect to the remote
485 host, you should change the default connection and transfer method
486 that @value{tramp} uses. There are several different methods that @value{tramp}
487 can use to connect to remote machines and transfer files
488 (@pxref{Connection types}).
490 If you don't know which method is right for you, see @xref{Default
495 * Connection types:: Types of connections made to remote machines.
496 * Inline methods:: Inline methods.
497 * External methods:: External methods.
499 * GVFS based methods:: GVFS based external methods.
502 * Gateway methods:: Gateway methods.
504 * Default Method:: Selecting a default method.
505 Here we also try to help those who
506 don't have the foggiest which method
508 * Default User:: Selecting a default user.
509 * Default Host:: Selecting a default host.
510 * Multi-hops:: Connecting to a remote host using multiple hops.
511 * Customizing Methods:: Using Non-Standard Methods.
512 * Customizing Completion:: Selecting config files for user/host name completion.
513 * Password handling:: Reusing passwords for several connections.
514 * Connection caching:: Reusing connection related information.
515 * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine.
516 * Remote shell setup:: Remote shell setup hints.
517 * Windows setup hints:: Issues with Cygwin ssh.
518 * Auto-save and Backup:: Auto-save and Backup.
522 @node Connection types
523 @section Types of connections made to remote machines.
524 @cindex connection types, overview
526 There are two basic types of transfer methods, each with its own
527 advantages and limitations. Both types of connection make use of a
528 remote shell access program such as @command{rsh}, @command{ssh} or
529 @command{telnet} to connect to the remote machine.
531 This connection is used to perform many of the operations that @value{tramp}
532 requires to make the remote file system transparently accessible from
533 the local machine. It is only when visiting files that the methods
536 @cindex inline methods
537 @cindex external methods
538 @cindex methods, inline
539 @cindex methods, external
540 Loading or saving a remote file requires that the content of the file
541 be transfered between the two machines. The content of the file can
542 be transfered using one of two methods: the @dfn{inline method} over
543 the same connection used to log in to the remote machine, or the
544 @dfn{external method} through another connection using a remote copy
545 program such as @command{rcp}, @command{scp} or @command{rsync}.
547 The performance of the external methods is generally better than that
548 of the inline methods, at least for large files. This is caused by
549 the need to encode and decode the data when transferring inline.
551 The one exception to this rule are the @command{scp} based transfer
552 methods. While these methods do see better performance when actually
553 transferring files, the overhead of the cryptographic negotiation at
554 startup may drown out the improvement in file transfer times.
556 External methods should be configured such a way that they don't
557 require a password (with @command{ssh-agent}, or such alike). Modern
558 @command{scp} implementations offer options to reuse existing
559 @command{ssh} connections, see method @command{scpc}. If it isn't
560 possible, you should consider @ref{Password handling}, otherwise you
561 will be prompted for a password every copy action.
565 @section Inline methods
566 @cindex inline methods
567 @cindex methods, inline
569 The inline methods in @value{tramp} are quite powerful and can work in
570 situations where you cannot use an external transfer program to connect.
571 Inline methods are the only methods that work when connecting to the
572 remote machine via telnet. (There are also strange inline methods which
573 allow you to transfer files between @emph{user identities} rather than
576 These methods depend on the existence of a suitable encoding and
577 decoding command on remote machine. Locally, @value{tramp} may be able to
578 use features of @value{emacsname} to decode and encode the files or
579 it may require access to external commands to perform that task.
583 @cindex base-64 encoding
584 @value{tramp} checks the availability and usability of commands like
585 @command{mimencode} (part of the @command{metamail} package) or
586 @command{uuencode} on the remote host. The first reliable command
587 will be used. The search path can be customized, see @ref{Remote
590 If both commands aren't available on the remote host, @value{tramp}
591 transfers a small piece of Perl code to the remote host, and tries to
592 apply it for encoding and decoding.
594 The variable @var{tramp-inline-compress-start-size} controls, whether
595 a file shall be compressed before encoding. This could increase
596 transfer speed for large text files.
604 Connect to the remote host with @command{rsh}. Due to the unsecure
605 connection it is recommended for very local host topology only.
607 On operating systems which provide the command @command{remsh} instead
608 of @command{rsh}, you can use the method @option{remsh}. This is true
609 for HP-UX or Cray UNICOS, for example.
616 Connect to the remote host with @command{ssh}. This is identical to
617 the previous option except that the @command{ssh} package is used,
618 making the connection more secure.
620 There are also two variants, @option{ssh1} and @option{ssh2}, that
621 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
622 explicitly select whether you want to use the SSH protocol version 1
623 or 2 to connect to the remote host. (You can also specify in
624 @file{~/.ssh/config}, the SSH configuration file, which protocol
625 should be used, and use the regular @option{ssh} method.)
627 Two other variants, @option{ssh1_old} and @option{ssh2_old}, use the
628 @command{ssh1} and @command{ssh2} commands explicitly. If you don't
629 know what these are, you do not need these options.
631 All the methods based on @command{ssh} have an additional feature: you
632 can specify a host name which looks like @file{host#42} (the real host
633 name, then a hash sign, then a port number). This means to connect to
634 the given host but to also pass @code{-p 42} as arguments to the
635 @command{ssh} command.
638 @item @option{telnet}
639 @cindex method telnet
640 @cindex telnet method
642 Connect to the remote host with @command{telnet}. This is as unsecure
643 as the @option{rsh} method.
650 This method does not connect to a remote host at all, rather it uses
651 the @command{su} program to allow you to edit files as another user.
652 That means, the specified host name in the file name must be either
653 @samp{localhost} or the host name as returned by the function
654 @command{(system-name)}. For an exception of this rule see
662 This is similar to the @option{su} method, but it uses @command{sudo}
663 rather than @command{su} to become a different user.
665 Note that @command{sudo} must be configured to allow you to start a
666 shell as the user. It would be nice if it was sufficient if
667 @command{ls} and @command{mimencode} were allowed, but that is not
668 easy to implement, so I haven't got around to it, yet.
675 As you would expect, this is similar to @option{ssh}, only a little
676 different. Whereas @option{ssh} opens a normal interactive shell on
677 the remote host, this option uses @samp{ssh -t -t @var{host} -l
678 @var{user} /bin/sh} to open a connection. This is useful for users
679 where the normal login shell is set up to ask them a number of
680 questions when logging in. This procedure avoids these questions, and
681 just gives @value{tramp} a more-or-less `standard' login shell to work
684 Note that this procedure does not eliminate questions asked by
685 @command{ssh} itself. For example, @command{ssh} might ask ``Are you
686 sure you want to continue connecting?'' if the host key of the remote
687 host is not known. @value{tramp} does not know how to deal with such a
688 question (yet), therefore you will need to make sure that you can log
689 in without such questions.
691 This is also useful for Windows users where @command{ssh}, when
692 invoked from an @value{emacsname} buffer, tells them that it is not
693 allocating a pseudo tty. When this happens, the login shell is wont
694 to not print any shell prompt, which confuses @value{tramp} mightily.
696 This supports the @samp{-p} argument.
699 @item @option{krlogin}
700 @cindex method krlogin
701 @cindex krlogin method
702 @cindex Kerberos (with krlogin method)
704 This method is also similar to @option{ssh}. It only uses the
705 @command{krlogin -x} command to log in to the remote host.
712 This method is mostly interesting for Windows users using the PuTTY
713 implementation of SSH. It uses @samp{plink -ssh} to log in to the
716 This supports the @samp{-P} argument.
718 Additionally, the methods @option{plink1} and @option{plink2} are
719 provided, which call @samp{plink -1 -ssh} or @samp{plink -2 -ssh} in
720 order to use SSH protocol version 1 or 2 explicitly.
722 CCC: Do we have to connect to the remote host once from the command
723 line to accept the SSH key? Maybe this can be made automatic?
725 CCC: Say something about the first shell command failing. This might
726 be due to a wrong setting of @code{tramp-rsh-end-of-line}.
729 @item @option{plinkx}
730 @cindex method plinkx
731 @cindex plinkx method
733 Another method using PuTTY on Windows. Instead of host names, it
734 expects PuTTY session names, calling @samp{plink -load @var{session}
735 -t"}. User names are relevant only in case the corresponding session
736 hasn't defined a user name. Different port numbers must be defined in
744 This is an experimental implementation of the fish protocol, known from
745 the GNU Midnight Commander or the KDE Konqueror. @value{tramp} expects
746 the fish server implementation from the KDE kioslave. That means, the
747 file @file{~/.fishsrv.pl} is expected to reside on the remote host.
749 The implementation lacks good performance. The code is offered anyway,
750 maybe somebody can improve the performance.
755 @node External methods
756 @section External methods
757 @cindex methods, external
758 @cindex external methods
760 The external methods operate through multiple channels, using the
761 remote shell connection for many actions while delegating file
762 transfers to an external transfer utility.
764 This saves the overhead of encoding and decoding that multiplexing the
765 transfer through the one connection has with the inline methods.
767 Since external methods need their own overhead opening a new channel,
768 all files which are smaller than @var{tramp-copy-size-limit} are still
769 transferred with the corresponding inline method. It should provide a
770 fair trade-off between both approaches.
773 @item @option{rcp} --- @command{rsh} and @command{rcp}
776 @cindex rcp (with rcp method)
777 @cindex rsh (with rcp method)
779 This method uses the @command{rsh} and @command{rcp} commands to connect
780 to the remote machine and transfer files. This is probably the fastest
781 connection method available.
783 The alternative method @option{remcp} uses the @command{remsh} and
784 @command{rcp} commands. It should be applied on machines where
785 @command{remsh} is used instead of @command{rsh}.
788 @item @option{scp} --- @command{ssh} and @command{scp}
791 @cindex scp (with scp method)
792 @cindex ssh (with scp method)
794 Using @command{ssh} to connect to the remote host and @command{scp} to
795 transfer files between the machines is the best method for securely
796 connecting to a remote machine and accessing files.
798 The performance of this option is also quite good. It may be slower than
799 the inline methods when you often open and close small files however.
800 The cost of the cryptographic handshake at the start of an @command{scp}
801 session can begin to absorb the advantage that the lack of encoding and
804 There are also two variants, @option{scp1} and @option{scp2}, that
805 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
806 explicitly select whether you want to use the SSH protocol version 1
807 or 2 to connect to the remote host. (You can also specify in
808 @file{~/.ssh/config}, the SSH configuration file, which protocol
809 should be used, and use the regular @option{scp} method.)
811 Two other variants, @option{scp1_old} and @option{scp2_old}, use the
812 @command{ssh1} and @command{ssh2} commands explicitly. If you don't
813 know what these are, you do not need these options.
815 All the @command{ssh} based methods support the @samp{-p} feature
816 where you can specify a port number to connect to in the host name.
817 For example, the host name @file{host#42} tells @value{tramp} to
818 specify @samp{-p 42} in the argument list for @command{ssh}, and to
819 specify @samp{-P 42} in the argument list for @command{scp}.
822 @item @option{sftp} --- @command{ssh} and @command{sftp}
825 @cindex sftp (with sftp method)
826 @cindex ssh (with sftp method)
828 That is mostly the same method as @option{scp}, but using
829 @command{sftp} as transfer command. So the same remarks are valid.
831 This command does not work like @value{ftppackagename}, where
832 @command{ftp} is called interactively, and all commands are send from
833 within this session. Instead of, @command{ssh} is used for login.
835 This method supports the @samp{-p} argument.
838 @item @option{rsync} --- @command{ssh} and @command{rsync}
841 @cindex rsync (with rsync method)
842 @cindex ssh (with rsync method)
844 Using the @command{ssh} command to connect securely to the remote
845 machine and the @command{rsync} command to transfer files is almost
846 identical to the @option{scp} method.
848 While @command{rsync} performs much better than @command{scp} when
849 transferring files that exist on both hosts, this advantage is lost if
850 the file exists only on one side of the connection. A file can exists
851 on both the remote and local host, when you copy a file from/to a
852 remote host. When you just open a file from the remote host (or write
853 a file there), a temporary file on the local side is kept as long as
854 the corresponding buffer, visiting this file, is alive.
856 This method supports the @samp{-p} argument.
859 @item @option{scpx} --- @command{ssh} and @command{scp}
862 @cindex scp (with scpx method)
863 @cindex ssh (with scpx method)
865 As you would expect, this is similar to @option{scp}, only a little
866 different. Whereas @option{scp} opens a normal interactive shell on
867 the remote host, this option uses @samp{ssh -t -t @var{host} -l
868 @var{user} /bin/sh} to open a connection. This is useful for users
869 where the normal login shell is set up to ask them a number of
870 questions when logging in. This procedure avoids these questions, and
871 just gives @value{tramp} a more-or-less `standard' login shell to work
874 This is also useful for Windows users where @command{ssh}, when
875 invoked from an @value{emacsname} buffer, tells them that it is not
876 allocating a pseudo tty. When this happens, the login shell is wont
877 to not print any shell prompt, which confuses @value{tramp} mightily.
879 This method supports the @samp{-p} argument.
882 @item @option{scpc} --- @command{ssh} and @command{scp}
885 @cindex scp (with scpc method)
886 @cindex ssh (with scpc method)
888 Newer versions of @option{ssh} (for example OpenSSH 4) offer an option
889 @option{ControlMaster}. This allows @option{scp} to reuse an existing
890 @option{ssh} channel, which increases performance.
892 Before you use this method, you shall check whether your @option{ssh}
893 implementation does support this option. Try from the command line
896 ssh localhost -o ControlMaster=yes
899 This method supports the @samp{-p} argument.
902 @item @option{rsyncc} --- @command{ssh} and @command{rsync}
903 @cindex method rsyncc
904 @cindex rsyncc method
905 @cindex rsync (with rsyncc method)
906 @cindex ssh (with rsyncc method)
908 Like the @option{scpc} method, @option{rsyncc} improves the underlying
909 @command{ssh} connection by the option @option{ControlMaster}. This
910 allows @command{rsync} to reuse an existing @command{ssh} channel,
911 which increases performance.
913 This method supports the @samp{-p} argument.
916 @item @option{pscp} --- @command{plink} and @command{pscp}
919 @cindex pscp (with pscp method)
920 @cindex plink (with pscp method)
921 @cindex PuTTY (with pscp method)
923 This method is similar to @option{scp}, but it uses the
924 @command{plink} command to connect to the remote host, and it uses
925 @command{pscp} for transferring the files. These programs are part
926 of PuTTY, an SSH implementation for Windows.
928 This method supports the @samp{-P} argument.
931 @item @option{psftp} --- @command{plink} and @command{psftp}
934 @cindex psftp (with psftp method)
935 @cindex plink (with psftp method)
936 @cindex PuTTY (with psftp method)
938 As you would expect, this method is similar to @option{sftp}, but it
939 uses the @command{plink} command to connect to the remote host, and it
940 uses @command{psftp} for transferring the files. These programs are
941 part of PuTTY, an SSH implementation for Windows.
943 This method supports the @samp{-P} argument.
946 @item @option{fcp} --- @command{fsh} and @command{fcp}
949 @cindex fsh (with fcp method)
950 @cindex fcp (with fcp method)
952 This method is similar to @option{scp}, but it uses the @command{fsh}
953 command to connect to the remote host, and it uses @command{fcp} for
954 transferring the files. @command{fsh/fcp} are a front-end for
955 @command{ssh} which allow for reusing the same @command{ssh} session
956 for submitting several commands. This avoids the startup overhead of
957 @command{scp} (which has to establish a secure connection whenever it
958 is called). Note, however, that you can also use one of the inline
959 methods to achieve a similar effect.
961 This method uses the command @samp{fsh @var{host} -l @var{user}
962 /bin/sh -i} to establish the connection, it does not work to just say
963 @command{fsh @var{host} -l @var{user}}.
968 There is no inline method using @command{fsh} as the multiplexing
969 provided by the program is not very useful in our context. @value{tramp}
970 opens just one connection to the remote host and then keeps it open,
978 This is not a native @value{tramp} method. Instead of, it forwards all
979 requests to @value{ftppackagename}.
981 This works only for unified filenames, see @ref{Issues}.
985 @item @option{smb} --- @command{smbclient}
989 This is another not natural @value{tramp} method. It uses the
990 @command{smbclient} command on different Unices in order to connect to
991 an SMB server. An SMB server might be a Samba (or CIFS) server on
992 another UNIX host or, more interesting, a host running MS Windows. So
993 far, it is tested towards MS Windows NT, MS Windows 2000, and MS
996 The first directory in the localname must be a share name on the remote
997 host. Remember, that the @code{$} character in which default shares
998 usually end, must be written @code{$$} due to environment variable
999 substitution in file names. If no share name is given (i.e. remote
1000 directory @code{/}), all available shares are listed.
1002 Since authorization is done on share level, you will be prompted
1003 always for a password if you access another share on the same host.
1004 This can be suppressed by @ref{Password handling}.
1006 MS Windows uses for authorization both a user name and a domain name.
1007 Because of this, the @value{tramp} syntax has been extended: you can
1008 specify a user name which looks like @code{user%domain} (the real user
1009 name, then a percent sign, then the domain name). So, to connect to
1010 the machine @code{melancholia} as user @code{daniel} of the domain
1011 @code{BIZARRE}, and edit @file{.emacs} in the home directory (share
1012 @code{daniel$}) I would specify the filename @file{@trampfn{smb,
1013 daniel%BIZARRE, melancholia, /daniel$$/.emacs}}.
1015 Depending on the Windows domain configuration, a Windows user might be
1016 considered as domain user per default. In order to connect as local
1017 user, the WINS name of that machine must be given as domain name.
1018 Usually, it is the machine name in capital letters. In the example
1019 above, the local user @code{daniel} would be specified as
1020 @file{@trampfn{smb, daniel%MELANCHOLIA, melancholia, /daniel$$/.emacs}}.
1022 The domain name as well as the user name are optional. If no user
1023 name is specified at all, the anonymous user (without password
1024 prompting) is assumed. This is different from all other @value{tramp}
1025 methods, where in such a case the local user name is taken.
1027 The @option{smb} method supports the @samp{-p} argument.
1029 @strong{Please note:} If @value{emacsname} runs locally under MS
1030 Windows, this method isn't available. Instead of, you can use UNC
1031 file names like @file{//melancholia/daniel$$/.emacs}. The only
1032 disadvantage is that there's no possibility to specify another user
1039 @cindex method imaps
1041 @cindex imaps method
1043 Accessing an IMAP mailbox is intended to save files there as encrypted
1044 message. It could be used in case there are no other remote file
1047 @value{tramp} supports both @option{imap} and @option{imaps} methods.
1048 The latter one accesses the IMAP server over ssl.
1050 Both methods support the port number specification.
1052 Note, that special handling is needed for declaring a passphrase for
1053 encryption / decryption of the messages (@pxref{Using an
1054 authentication file}).
1061 @node GVFS based methods
1062 @section GVFS based external methods
1063 @cindex methods, gvfs
1064 @cindex gvfs based methods
1067 The connection methods described in this section are based on GVFS
1068 @uref{http://en.wikipedia.org/wiki/GVFS}. Via GVFS, the remote
1069 filesystem is mounted locally through FUSE. @value{tramp} uses
1070 internally this local mounted directory.
1072 The communication with GVFS is implemented via D-Bus messages.
1073 Therefore, your @value{emacsname} must have D-Bus integration,
1074 @pxref{Top, , D-Bus, dbus}.
1083 This method provides access to WebDAV files and directories. There
1084 exists also the external method @option{davs}, which uses SSL
1085 encryption for the access.
1087 Both methods support the port number specification as discussed above.
1094 OBEX is an FTP-like access protocol for simple devices, like cell
1095 phones. Until now @value{tramp} supports only OBEX over Bluetooth.
1098 @item @option{synce}
1099 @cindex method synce
1100 @cindex synce method
1102 The @option{synce} method allows communication with Windows Mobile
1103 devices. Beside GVFS for mounting remote files and directories via
1104 FUSE, it needs also the SYNCE-GVFS plugin.
1107 @defopt tramp-gvfs-methods
1108 This customer option, a list, defines the external methods, which
1109 shall be used with GVFS. Per default, these are @option{dav},
1110 @option{davs}, @option{obex} and @option{synce}. Other possible
1111 values are @option{ftp}, @option{sftp} and @option{smb}.
1117 @node Gateway methods
1118 @section Gateway methods
1119 @cindex methods, gateway
1120 @cindex gateway methods
1122 Gateway methods are not methods to access a remote host directly.
1123 These methods are intended to pass firewalls or proxy servers.
1124 Therefore, they can be used for proxy host declarations
1125 (@pxref{Multi-hops}) only.
1127 A gateway method must come always along with a method who supports
1128 port setting. This is because @value{tramp} targets the accompanied
1129 method to @file{localhost#random_port}, from where the firewall or
1130 proxy server is accessed to.
1132 Gateway methods support user name and password declarations. These
1133 are used to authenticate towards the corresponding firewall or proxy
1134 server. They can be passed only if your friendly administrator has
1135 granted your access.
1138 @item @option{tunnel}
1139 @cindex method tunnel
1140 @cindex tunnel method
1142 This method implements an HTTP tunnel via the @command{CONNECT}
1143 command (see RFC 2616, 2817). Any HTTP 1.1 compliant (proxy) server
1144 shall support this command.
1146 As authentication method, only @option{Basic Authentication} (see RFC
1147 2617) is implemented so far. If no port number is given in the
1148 declaration, port @option{8080} is used for the proxy server.
1151 @item @option{socks}
1152 @cindex method socks
1153 @cindex socks method
1155 The @command{socks} method provides access to SOCKSv5 servers (see
1156 RFC 1928). @option{Username/Password Authentication} according to RFC
1159 The default port number of the socks server is @option{1080}, if not
1160 specified otherwise.
1166 @node Default Method
1167 @section Selecting a default method
1168 @cindex default method
1170 @vindex tramp-default-method
1171 When you select an appropriate transfer method for your typical usage
1172 you should set the variable @code{tramp-default-method} to reflect that
1173 choice. This variable controls which method will be used when a method
1174 is not specified in the @value{tramp} file name. For example:
1177 (setq tramp-default-method "ssh")
1180 @vindex tramp-default-method-alist
1181 You can also specify different methods for certain user/host
1182 combinations, via the variable @code{tramp-default-method-alist}. For
1183 example, the following two lines specify to use the @option{ssh}
1184 method for all user names matching @samp{john} and the @option{rsync}
1185 method for all host names matching @samp{lily}. The third line
1186 specifies to use the @option{su} method for the user @samp{root} on
1187 the machine @samp{localhost}.
1190 (add-to-list 'tramp-default-method-alist '("" "john" "ssh"))
1191 (add-to-list 'tramp-default-method-alist '("lily" "" "rsync"))
1192 (add-to-list 'tramp-default-method-alist
1193 '("\\`localhost\\'" "\\`root\\'" "su"))
1197 See the documentation for the variable
1198 @code{tramp-default-method-alist} for more details.
1200 External methods are normally preferable to inline methods, giving
1203 @xref{Inline methods}.
1204 @xref{External methods}.
1206 Another consideration with the selection of transfer methods is the
1207 environment you will use them in and, especially when used over the
1208 Internet, the security implications of your preferred method.
1210 The @option{rsh} and @option{telnet} methods send your password as
1211 plain text as you log in to the remote machine, as well as
1212 transferring the files in such a way that the content can easily be
1213 read from other machines.
1215 If you need to connect to remote systems that are accessible from the
1216 Internet, you should give serious thought to using @option{ssh} based
1217 methods to connect. These provide a much higher level of security,
1218 making it a non-trivial exercise for someone to obtain your password
1219 or read the content of the files you are editing.
1222 @subsection Which method is the right one for me?
1223 @cindex choosing the right method
1225 Given all of the above, you are probably thinking that this is all fine
1226 and good, but it's not helping you to choose a method! Right you are.
1227 As a developer, we don't want to boss our users around but give them
1228 maximum freedom instead. However, the reality is that some users would
1229 like to have some guidance, so here I'll try to give you this guidance
1230 without bossing you around. You tell me whether it works @dots{}
1232 My suggestion is to use an inline method. For large files, external
1233 methods might be more efficient, but I guess that most people will
1234 want to edit mostly small files. And if you access large text files,
1235 compression (driven by @var{tramp-inline-compress-start-size}) shall
1236 still result in good performance.
1238 I guess that these days, most people can access a remote machine by
1239 using @command{ssh}. So I suggest that you use the @option{ssh}
1240 method. So, type @kbd{C-x C-f @trampfn{ssh, root, otherhost,
1241 /etc/motd} @key{RET}} to edit the @file{/etc/motd} file on the other
1244 If you can't use @option{ssh} to log in to the remote host, then
1245 select a method that uses a program that works. For instance, Windows
1246 users might like the @option{plink} method which uses the PuTTY
1247 implementation of @command{ssh}. Or you use Kerberos and thus like
1250 For the special case of editing files on the local host as another
1251 user, see the @option{su} or @option{sudo} methods. They offer
1252 shortened syntax for the @samp{root} account, like
1253 @file{@trampfn{su, , , /etc/motd}}.
1255 People who edit large files may want to consider @option{scpc} instead
1256 of @option{ssh}, or @option{pscp} instead of @option{plink}. These
1257 external methods are faster than inline methods for large files.
1258 Note, however, that external methods suffer from some limitations.
1259 Please try first whether you really get a noticeable speed advantage
1260 from using an external method! Maybe even for large files, inline
1261 methods are fast enough.
1265 @section Selecting a default user
1266 @cindex default user
1268 The user part of a @value{tramp} file name can be omitted. Usually,
1269 it is replaced by the user name you are logged in. Often, this is not
1270 what you want. A typical use of @value{tramp} might be to edit some
1271 files with root permissions on the local host. This case, you should
1272 set the variable @code{tramp-default-user} to reflect that choice.
1276 (setq tramp-default-user "root")
1279 @code{tramp-default-user} is regarded as obsolete, and will be removed
1282 @vindex tramp-default-user-alist
1283 You can also specify different users for certain method/host
1284 combinations, via the variable @code{tramp-default-user-alist}. For
1285 example, if you always have to use the user @samp{john} in the domain
1286 @samp{somewhere.else}, you can specify the following:
1289 (add-to-list 'tramp-default-user-alist
1290 '("ssh" ".*\\.somewhere\\.else\\'" "john"))
1294 See the documentation for the variable
1295 @code{tramp-default-user-alist} for more details.
1297 One trap to fall in must be known. If @value{tramp} finds a default
1298 user, this user will be passed always to the connection command as
1299 parameter (for example @samp{ssh here.somewhere.else -l john}. If you
1300 have specified another user for your command in its configuration
1301 files, @value{tramp} cannot know it, and the remote access will fail.
1302 If you have specified in the given example in @file{~/.ssh/config} the
1306 Host here.somewhere.else
1311 than you must discard selecting a default user by @value{tramp}. This
1312 will be done by setting it to @code{nil} (or @samp{lily}, likewise):
1315 (add-to-list 'tramp-default-user-alist
1316 '("ssh" "\\`here\\.somewhere\\.else\\'" nil))
1319 The last entry in @code{tramp-default-user-alist} could be your
1320 default user you'll apply predominantly. You shall @emph{append} it
1321 to that list at the end:
1324 (add-to-list 'tramp-default-user-alist '(nil nil "jonas") t)
1329 @section Selecting a default host
1330 @cindex default host
1332 @vindex tramp-default-host
1333 Finally, it is even possible to omit the host name part of a
1334 @value{tramp} file name. This case, the value of the variable
1335 @code{tramp-default-host} is used. Per default, it is initialized
1336 with the host name your local @value{emacsname} is running.
1338 If you, for example, use @value{tramp} mainly to contact the host
1339 @samp{target} as user @samp{john}, you can specify:
1342 (setq tramp-default-user "john"
1343 tramp-default-host "target")
1346 Then the simple file name @samp{@trampfn{ssh, , ,}} will connect you
1347 to John's home directory on target.
1349 Note, however, that the most simplification @samp{/::} won't work,
1350 because @samp{/:} is the prefix for quoted file names.
1355 @section Connecting to a remote host using multiple hops
1359 Sometimes, the methods described before are not sufficient. Sometimes,
1360 it is not possible to connect to a remote host using a simple command.
1361 For example, if you are in a secured network, you might have to log in
1362 to a `bastion host' first before you can connect to the outside world.
1363 Of course, the target host may also require a bastion host.
1365 @vindex tramp-default-proxies-alist
1366 In order to specify such multiple hops, it is possible to define a proxy
1367 host to pass through, via the variable
1368 @code{tramp-default-proxies-alist}. This variable keeps a list of
1369 triples (@var{host} @var{user} @var{proxy}).
1371 The first matching item specifies the proxy host to be passed for a
1372 file name located on a remote target matching @var{user}@@@var{host}.
1373 @var{host} and @var{user} are regular expressions or @code{nil}, which
1374 is interpreted as a regular expression which always matches.
1376 @var{proxy} must be a Tramp filename which localname part is ignored.
1377 Method and user name on @var{proxy} are optional, which is interpreted
1378 with the default values.
1380 The method must be an inline or gateway method (@pxref{Inline
1381 methods}, @pxref{Gateway methods}).
1384 The method must be an inline method (@pxref{Inline methods}).
1386 If @var{proxy} is @code{nil}, no additional hop is required reaching
1387 @var{user}@@@var{host}.
1389 If you, for example, must pass the host @samp{bastion.your.domain} as
1390 user @samp{bird} for any remote host which is not located in your local
1394 (add-to-list 'tramp-default-proxies-alist
1395 '("\\." nil "@trampfn{ssh, bird, bastion.your.domain,}"))
1396 (add-to-list 'tramp-default-proxies-alist
1397 '("\\.your\\.domain\\'" nil nil))
1400 Please note the order of the code. @code{add-to-list} adds elements at the
1401 beginning of a list. Therefore, most relevant rules must be added last.
1403 Proxy hosts can be cascaded. If there is another host called
1404 @samp{jump.your.domain}, which is the only one in your local domain who
1405 is allowed connecting @samp{bastion.your.domain}, you can add another
1409 (add-to-list 'tramp-default-proxies-alist
1410 '("\\`bastion\\.your\\.domain\\'"
1412 "@trampfn{ssh, , jump.your.domain,}"))
1415 @var{proxy} can contain the patterns @code{%h} or @code{%u}. These
1416 patterns are replaced by the strings matching @var{host} or
1417 @var{user}, respectively.
1419 If you, for example, wants to work as @samp{root} on hosts in the
1420 domain @samp{your.domain}, but login as @samp{root} is disabled for
1421 non-local access, you might add the following rule:
1424 (add-to-list 'tramp-default-proxies-alist
1425 '("\\.your\\.domain\\'" "\\`root\\'" "@trampfn{ssh, , %h,}"))
1428 Opening @file{@trampfn{sudo, , randomhost.your.domain,}} would connect
1429 first @samp{randomhost.your.domain} via @code{ssh} under your account
1430 name, and perform @code{sudo -u root} on that host afterwards. It is
1431 important to know that the given method is applied on the host which
1432 has been reached so far. @code{sudo -u root}, applied on your local
1433 host, wouldn't be useful here.
1435 @var{host}, @var{user} and @var{proxy} can also be Lisp forms. These
1436 forms are evaluated, and must return a string, or @code{nil}. The
1437 previous example could be generalized then: For all hosts except my
1438 local one connect via @code{ssh} first, and apply @code{sudo -u root}
1442 (add-to-list 'tramp-default-proxies-alist
1443 '(nil "\\`root\\'" "@trampfn{ssh, , %h,}"))
1444 (add-to-list 'tramp-default-proxies-alist
1445 '((regexp-quote (system-name)) nil nil))
1448 This is the recommended configuration to work as @samp{root} on remote
1452 Finally, @code{tramp-default-proxies-alist} can be used to pass
1453 firewalls or proxy servers. Imagine your local network has a host
1454 @samp{proxy.your.domain} which is used on port 3128 as HTTP proxy to
1455 the outer world. Your friendly administrator has granted you access
1456 under your user name to @samp{host.other.domain} on that proxy
1457 server.@footnote{HTTP tunnels are intended for secure SSL/TLS
1458 communication. Therefore, many proxy server restrict the tunnels to
1459 related target ports. You might need to run your ssh server on your
1460 target host @samp{host.other.domain} on such a port, like 443 (https).
1461 See @uref{http://savannah.gnu.org/maintenance/CvsFromBehindFirewall}
1462 for discussion of ethical issues.} You would need to add the
1466 (add-to-list 'tramp-default-proxies-alist
1467 '("\\`host\\.other\\.domain\\'" nil
1468 "@trampfn{tunnel, , proxy.your.domain#3128,}"))
1471 Gateway methods can be declared as first hop only in a multiple hop
1476 @node Customizing Methods
1477 @section Using Non-Standard Methods
1478 @cindex customizing methods
1479 @cindex using non-standard methods
1480 @cindex create your own methods
1482 There is a variable @code{tramp-methods} which you can change if the
1483 predefined methods don't seem right.
1485 For the time being, I'll refer you to the Lisp documentation of that
1486 variable, accessible with @kbd{C-h v tramp-methods @key{RET}}.
1489 @node Customizing Completion
1490 @section Selecting config files for user/host name completion
1491 @cindex customizing completion
1492 @cindex selecting config files
1493 @vindex tramp-completion-function-alist
1495 The variable @code{tramp-completion-function-alist} is intended to
1496 customize which files are taken into account for user and host name
1497 completion (@pxref{Filename completion}). For every method, it keeps
1498 a set of configuration files, accompanied by a Lisp function able to
1499 parse that file. Entries in @code{tramp-completion-function-alist}
1500 have the form (@var{method} @var{pair1} @var{pair2} ...).
1502 Each @var{pair} is composed of (@var{function} @var{file}).
1503 @var{function} is responsible to extract user names and host names
1504 from @var{file} for completion. There are two functions which access
1507 @defun tramp-get-completion-function method
1508 This function returns the list of completion functions for @var{method}.
1512 (tramp-get-completion-function "rsh")
1514 @result{} ((tramp-parse-rhosts "/etc/hosts.equiv")
1515 (tramp-parse-rhosts "~/.rhosts"))
1519 @defun tramp-set-completion-function method function-list
1520 This function sets @var{function-list} as list of completion functions
1525 (tramp-set-completion-function "ssh"
1526 '((tramp-parse-sconfig "/etc/ssh_config")
1527 (tramp-parse-sconfig "~/.ssh/config")))
1529 @result{} ((tramp-parse-sconfig "/etc/ssh_config")
1530 (tramp-parse-sconfig "~/.ssh/config"))
1534 The following predefined functions parsing configuration files exist:
1537 @item @code{tramp-parse-rhosts}
1538 @findex tramp-parse-rhosts
1540 This function parses files which are syntactical equivalent to
1541 @file{~/.rhosts}. It returns both host names and user names, if
1544 @item @code{tramp-parse-shosts}
1545 @findex tramp-parse-shosts
1547 This function parses files which are syntactical equivalent to
1548 @file{~/.ssh/known_hosts}. Since there are no user names specified
1549 in such files, it can return host names only.
1551 @item @code{tramp-parse-sconfig}
1552 @findex tramp-parse-shosts
1554 This function returns the host nicknames defined by @code{Host} entries
1555 in @file{~/.ssh/config} style files.
1557 @item @code{tramp-parse-shostkeys}
1558 @findex tramp-parse-shostkeys
1560 SSH2 parsing of directories @file{/etc/ssh2/hostkeys/*} and
1561 @file{~/ssh2/hostkeys/*}. Hosts are coded in file names
1562 @file{hostkey_@var{portnumber}_@var{host-name}.pub}. User names
1563 are always @code{nil}.
1565 @item @code{tramp-parse-sknownhosts}
1566 @findex tramp-parse-shostkeys
1568 Another SSH2 style parsing of directories like
1569 @file{/etc/ssh2/knownhosts/*} and @file{~/ssh2/knownhosts/*}. This
1570 case, hosts names are coded in file names
1571 @file{@var{host-name}.@var{algorithm}.pub}. User names are always @code{nil}.
1573 @item @code{tramp-parse-hosts}
1574 @findex tramp-parse-hosts
1576 A function dedicated to @file{/etc/hosts} style files. It returns
1579 @item @code{tramp-parse-passwd}
1580 @findex tramp-parse-passwd
1582 A function which parses @file{/etc/passwd} like files. Obviously, it
1583 can return user names only.
1585 @item @code{tramp-parse-netrc}
1586 @findex tramp-parse-netrc
1588 Finally, a function which parses @file{~/.netrc} like files.
1591 If you want to keep your own data in a file, with your own structure,
1592 you might provide such a function as well. This function must meet
1593 the following conventions:
1595 @defun my-tramp-parse file
1596 @var{file} must be either a file name on your host, or @code{nil}.
1597 The function must return a list of (@var{user} @var{host}), which are
1598 taken as candidates for user and host name completion.
1602 (my-tramp-parse "~/.my-tramp-hosts")
1604 @result{} ((nil "toto") ("daniel" "melancholia"))
1609 @node Password handling
1610 @section Reusing passwords for several connections.
1613 Sometimes it is necessary to connect to the same remote host several
1614 times. Reentering passwords again and again would be annoying, when
1615 the chosen method does not support access without password prompt
1616 through own configuration.
1618 The best recommendation is to use the method's own mechanism for
1619 password handling. Consider @command{ssh-agent} for @option{ssh}-like
1620 methods, or @command{pageant} for @option{plink}-like methods.
1622 However, if you cannot apply such native password handling,
1623 @value{tramp} offers altenatives.
1626 @anchor{Using an authentication file}
1627 @subsection Using an authentication file
1629 @vindex auth-sources
1630 The package @file{auth-source.el}, originally developed in No Gnus,
1631 offers the possibility to read passwords from a file, like FTP does it
1632 from @file{~/.netrc}. The default authentication file is
1633 @file{~/.authinfo.gpg}, this can be changed via the variable
1634 @code{auth-sources}.
1637 A typical entry in the authentication file would be
1640 machine melancholia port scp login daniel password geheim
1643 The port can be any @value{tramp} method (@pxref{Inline methods},
1644 @pxref{External methods}), to match only this method. When you omit
1645 the port, you match all @value{tramp} methods.
1648 A special case are @option{imap}-like methods. Authentication with
1649 the IMAP server is performed via @file{imap.el}, there is no special
1650 need from @value{tramp} point of view. An additional passphrase, used
1651 for symmetric encryption and decryption of the stored messages, should
1652 be given with the special port indication @option{tramp-imap}:
1655 machine melancholia port tramp-imap login daniel password ultrageheim
1659 @anchor{Caching passwords}
1660 @subsection Caching passwords
1662 If there is no authentication file, @value{tramp} caches the passwords
1663 entered by you. They will be reused next time if a connection needs
1664 them for the same user name and host name, independently of the
1667 @vindex password-cache-expiry
1668 Passwords are not saved permanently, that means the password caching
1669 is limited to the lifetime of your @value{emacsname} session. You
1670 can influence the lifetime of password caching by customizing the
1671 variable @code{password-cache-expiry}. The value is the number of
1672 seconds how long passwords are cached. Setting it to @code{nil}
1673 disables the expiration.
1675 @vindex password-cache
1676 If you don't like this feature for security reasons, password caching
1677 can be disabled totally by customizing the variable
1678 @code{password-cache} (setting it to @code{nil}).
1680 Implementation Note: password caching is based on the package
1681 @file{password-cache.el}. For the time being, it is activated only
1682 when this package is seen in the @code{load-path} while loading
1684 @ifset installchapter
1685 If you don't use No Gnus, you can take @file{password.el} from the
1686 @value{tramp} @file{contrib} directory, see @ref{Installation
1691 @node Connection caching
1692 @section Reusing connection related information.
1695 @vindex tramp-persistency-file-name
1696 In order to reduce initial connection time, @value{tramp} stores
1697 connection related information persistently. The variable
1698 @code{tramp-persistency-file-name} keeps the file name where these
1699 information are written. Its default value is
1701 @file{~/.emacs.d/tramp}.
1704 @file{~/.xemacs/tramp}.
1706 It is recommended to choose a local file name.
1708 @value{tramp} reads this file during startup, and writes it when
1709 exiting @value{emacsname}. You can simply remove this file if
1710 @value{tramp} shall be urged to recompute these information next
1711 @value{emacsname} startup time.
1713 Using such persistent information can be disabled by setting
1714 @code{tramp-persistency-file-name} to @code{nil}.
1716 Once consequence of reusing connection related information is that
1717 @var{tramp} needs to distinguish hosts. If you, for example, run a
1718 local @code{sshd} on port 3001, which tunnels @command{ssh} to another
1719 host, you could access both @file{@trampfn{ssh, , localhost,}} and
1720 @file{@trampfn{ssh, , localhost#3001,}}. @var{tramp} would use the
1721 same host related information (like paths, Perl variants, etc) for
1722 both connections, although the information is valid only for one of
1725 In order to avoid trouble, you must use another host name for one of
1726 the connections, like introducing a @option{Host} section in
1727 @file{~/.ssh/config} (@pxref{Frequently Asked Questions}) or applying
1728 multiple hops (@pxref{Multi-hops}).
1730 When @value{tramp} detects a changed operating system version on a
1731 remote host (via the command @command{uname -sr}), it flushes all
1732 connection related information for this host, and opens the
1736 @node Remote Programs
1737 @section How @value{tramp} finds and uses programs on the remote machine.
1739 @value{tramp} depends on a number of programs on the remote host in order to
1740 function, including @command{ls}, @command{test}, @command{find} and
1743 In addition to these required tools, there are various tools that may be
1744 required based on the connection method. See @ref{Inline methods} and
1745 @ref{External methods} for details on these.
1747 Certain other tools, such as @command{perl} (or @command{perl5}) and
1748 @command{grep} will be used if they can be found. When they are
1749 available, they are used to improve the performance and accuracy of
1752 @vindex tramp-remote-path
1753 @vindex tramp-default-remote-path
1754 @vindex tramp-own-remote-path
1755 @defopt tramp-remote-path
1756 When @value{tramp} connects to the remote machine, it searches for the
1757 programs that it can use. The variable @code{tramp-remote-path}
1758 controls the directories searched on the remote machine.
1760 By default, this is set to a reasonable set of defaults for most
1761 machines. The symbol @code{tramp-default-remote-path} is a place
1762 holder, it is replaced by the list of directories received via the
1763 command @command{getconf PATH} on your remote machine. For example,
1764 on Debian GNU/Linux this is @file{/bin:/usr/bin}, whereas on Solaris
1765 this is @file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin}.
1766 It is recommended to apply this symbol on top of
1767 @code{tramp-remote-path}.
1769 It is possible, however, that your local (or remote ;) system
1770 administrator has put the tools you want in some obscure local
1773 In this case, you can still use them with @value{tramp}. You simply
1774 need to add code to your @file{.emacs} to add the directory to the
1775 remote path. This will then be searched by @value{tramp} when you
1776 connect and the software found.
1778 To add a directory to the remote search path, you could use code such
1782 @i{;; We load @value{tramp} to define the variable.}
1784 @i{;; We have @command{perl} in "/usr/local/perl/bin"}
1785 (add-to-list 'tramp-remote-path "/usr/local/perl/bin")
1788 Another possibility is to reuse the path settings of your remote
1789 account, when you log in. Usually, these settings are overwritten,
1790 because they might not be useful for @value{tramp}. The place holder
1791 @code{tramp-own-remote-path} preserves these settings. You can
1795 (add-to-list 'tramp-remote-path 'tramp-own-remote-path)
1799 @value{tramp} caches several information, like the Perl binary
1800 location. The changed remote search path wouldn't affect these
1801 settings. In order to force @value{tramp} to recompute these values,
1802 you must exit @value{emacsname}, remove your persistency file
1803 (@pxref{Connection caching}), and restart @value{emacsname}.
1806 @node Remote shell setup
1807 @section Remote shell setup hints
1808 @cindex remote shell setup
1809 @cindex @file{.profile} file
1810 @cindex @file{.login} file
1811 @cindex shell init files
1813 As explained in the @ref{Overview} section, @value{tramp} connects to the
1814 remote host and talks to the shell it finds there. Of course, when you
1815 log in, the shell executes its init files. Suppose your init file
1816 requires you to enter the birth date of your mother; clearly @value{tramp}
1817 does not know this and hence fails to log you in to that host.
1819 There are different possible strategies for pursuing this problem. One
1820 strategy is to enable @value{tramp} to deal with all possible situations.
1821 This is a losing battle, since it is not possible to deal with
1822 @emph{all} situations. The other strategy is to require you to set up
1823 the remote host such that it behaves like @value{tramp} expects. This might
1824 be inconvenient because you have to invest a lot of effort into shell
1825 setup before you can begin to use @value{tramp}.
1827 The package, therefore, pursues a combined approach. It tries to
1828 figure out some of the more common setups, and only requires you to
1829 avoid really exotic stuff. For example, it looks through a list of
1830 directories to find some programs on the remote host. And also, it
1831 knows that it is not obvious how to check whether a file exists, and
1832 therefore it tries different possibilities. (On some hosts and
1833 shells, the command @command{test -e} does the trick, on some hosts
1834 the shell builtin doesn't work but the program @command{/usr/bin/test
1835 -e} or @command{/bin/test -e} works. And on still other hosts,
1836 @command{ls -d} is the right way to do this.)
1838 Below you find a discussion of a few things that @value{tramp} does not deal
1839 with, and that you therefore have to set up correctly.
1842 @item @var{shell-prompt-pattern}
1843 @vindex shell-prompt-pattern
1845 After logging in to the remote host, @value{tramp} has to wait for the remote
1846 shell startup to finish before it can send commands to the remote
1847 shell. The strategy here is to wait for the shell prompt. In order to
1848 recognize the shell prompt, the variable @code{shell-prompt-pattern} has
1849 to be set correctly to recognize the shell prompt on the remote host.
1851 Note that @value{tramp} requires the match for @code{shell-prompt-pattern}
1852 to be at the end of the buffer. Many people have something like the
1853 following as the value for the variable: @code{"^[^>$][>$] *"}. Now
1854 suppose your shell prompt is @code{a <b> c $ }. In this case,
1855 @value{tramp} recognizes the @code{>} character as the end of the prompt,
1856 but it is not at the end of the buffer.
1858 @item @var{tramp-shell-prompt-pattern}
1859 @vindex tramp-shell-prompt-pattern
1861 This regular expression is used by @value{tramp} in the same way as
1862 @code{shell-prompt-pattern}, to match prompts from the remote shell.
1863 This second variable exists because the prompt from the remote shell
1864 might be different from the prompt from a local shell --- after all,
1865 the whole point of @value{tramp} is to log in to remote hosts as a
1866 different user. The default value of
1867 @code{tramp-shell-prompt-pattern} is the same as the default value of
1868 @code{shell-prompt-pattern}, which is reported to work well in many
1871 @item @var{tramp-password-prompt-regexp}
1872 @vindex tramp-password-prompt-regexp
1873 @vindex tramp-wrong-passwd-regexp
1875 During login, @value{tramp} might be forced to enter a password or a
1876 passphrase. The difference between both is that a password is
1877 requested from the shell on the remote host, while a passphrase is
1878 needed for accessing local authentication information, like your ssh
1881 @var{tramp-password-prompt-regexp} handles the detection of such
1882 requests for English environments. When you use another localization
1883 of your (local or remote) host, you might need to adapt this. Example:
1887 tramp-password-prompt-regexp
1891 '("passphrase" "Passphrase"
1893 "password" "Password"
1895 "passwort" "Passwort"
1897 "mot de passe" "Mot de passe") t)