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 repective 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,
41 2006, 2007, 2008, 2009 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}
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 * Version Control:: The inner workings of remote version control.
161 * Files directories and localnames:: How file names, directories and localnames are mangled and managed.
162 * Traces and Profiles:: How to Customize Traces.
163 * Issues:: Debatable Issues and What Was Decided.
165 * GNU Free Documentation License:: The license for this documentation.
168 --- The Detailed Node Listing ---
170 @ifset installchapter
171 Installing @value{tramp} with your @value{emacsname}
173 * Installation parameters:: Parameters in order to control installation.
174 * Load paths:: How to plug-in @value{tramp} into your environment.
175 * Japanese manual:: Japanese manual.
179 Configuring @value{tramp} for use
181 * Connection types:: Types of connections made to remote machines.
182 * Inline methods:: Inline methods.
183 * External methods:: External methods.
185 * GVFS based methods:: GVFS based external methods.
188 * Gateway methods:: Gateway methods.
190 * Default Method:: Selecting a default method.
191 * Default User:: Selecting a default user.
192 * Default Host:: Selecting a default host.
193 * Multi-hops:: Connecting to a remote host using multiple hops.
194 * Customizing Methods:: Using Non-Standard Methods.
195 * Customizing Completion:: Selecting config files for user/host name completion.
196 * Password handling:: Reusing passwords for several connections.
197 * Connection caching:: Reusing connection related information.
198 * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine.
199 * Remote shell setup:: Remote shell setup hints.
200 * Windows setup hints:: Issues with Cygwin ssh.
201 * Auto-save and Backup:: Auto-save and Backup.
205 * Filename Syntax:: @value{tramp} filename conventions.
206 * Alternative Syntax:: URL-like filename syntax.
207 * Filename completion:: Filename completion.
208 * Remote processes:: Integration with other @value{emacsname} packages.
209 * Cleanup remote connections:: Cleanup remote connections.
211 The inner workings of remote version control
213 * Version Controlled Files:: Determining if a file is under version control.
214 * Remote Commands:: Executing the version control commands on the remote machine.
215 * Changed workfiles:: Detecting if the working file has changed.
216 * Checking out files:: Bringing the workfile out of the repository.
217 * Miscellaneous Version Control:: Things related to Version Control that don't fit elsewhere.
219 Things related to Version Control that don't fit elsewhere
221 * Remote File Ownership:: How VC determines who owns a workfile.
222 * Back-end Versions:: How VC determines what release your RCS is.
224 How file names, directories and localnames are mangled and managed
226 * Localname deconstruction:: Breaking a localname into its components.
228 * External packages:: Integration with external Lisp packages.
235 @chapter An overview of @value{tramp}
238 After the installation of @value{tramp} into your @value{emacsname}, you
239 will be able to access files on remote machines as though they were
240 local. Access to the remote file system for editing files, version
241 control, and @code{dired} are transparently enabled.
243 Your access to the remote machine can be with the @command{rsh},
244 @command{rlogin}, @command{telnet} programs or with any similar
245 connection method. This connection must pass @acronym{ASCII}
246 successfully to be usable but need not be 8-bit clean.
248 The package provides support for @command{ssh} connections out of the
249 box, one of the more common uses of the package. This allows
250 relatively secure access to machines, especially if @command{ftp}
253 Under Windows, @value{tramp} is integrated with the PuTTY package,
254 using the @command{plink} program.
256 The majority of activity carried out by @value{tramp} requires only that
257 the remote login is possible and is carried out at the terminal. In
258 order to access remote files @value{tramp} needs to transfer their content
259 to the local machine temporarily.
261 @value{tramp} can transfer files between the machines in a variety of ways.
262 The details are easy to select, depending on your needs and the
263 machines in question.
265 The fastest transfer methods for large files rely on a remote file
266 transfer package such as @command{rcp}, @command{scp}, @command{rsync}
267 or (under Windows) @command{pscp}.
269 If the remote copy methods are not suitable for you, @value{tramp} also
270 supports the use of encoded transfers directly through the shell.
271 This requires that the @command{mimencode} or @command{uuencode} tools
272 are available on the remote machine. These methods are generally
273 faster for small files.
275 @value{tramp} is still under active development and any problems you encounter,
276 trivial or major, should be reported to the @value{tramp} developers.
280 @subsubheading Behind the scenes
281 @cindex behind the scenes
282 @cindex details of operation
285 This section tries to explain what goes on behind the scenes when you
286 access a remote file through @value{tramp}.
288 Suppose you type @kbd{C-x C-f} and enter part of an @value{tramp} file name,
289 then hit @kbd{@key{TAB}} for completion. Suppose further that this is
290 the first time that @value{tramp} is invoked for the host in question. Here's
295 @value{tramp} discovers that it needs a connection to the host. So it
296 invokes @samp{telnet @var{host}} or @samp{rsh @var{host} -l
297 @var{user}} or a similar tool to connect to the remote host.
298 Communication with this process happens through an
299 @value{emacsname} buffer, that is, the output from the remote end
303 The remote host may prompt for a login name (for @command{telnet}).
304 The login name is given in the file name, so @value{tramp} sends the
305 login name and a newline.
308 The remote host may prompt for a password or pass phrase (for
309 @command{rsh} or for @command{telnet} after sending the login name).
310 @value{tramp} displays the prompt in the minibuffer, asking you for the
311 password or pass phrase.
313 You enter the password or pass phrase. @value{tramp} sends it to the remote
314 host, followed by a newline.
317 @value{tramp} now waits for the shell prompt or for a message that the login
320 If @value{tramp} sees neither of them after a certain period of time
321 (a minute, say), then it issues an error message saying that it
322 couldn't find the remote shell prompt and shows you what the remote
325 If @value{tramp} sees a @samp{login failed} message, it tells you so,
326 aborts the login attempt and allows you to try again.
329 Suppose that the login was successful and @value{tramp} sees the shell prompt
330 from the remote host. Now @value{tramp} invokes @command{/bin/sh} because
331 Bourne shells and C shells have different command
332 syntaxes.@footnote{Invoking @command{/bin/sh} will fail if your login
333 shell doesn't recognize @samp{exec /bin/sh} as a valid command.
334 Maybe you use the Scheme shell @command{scsh}@dots{}}
336 After the Bourne shell has come up, @value{tramp} sends a few commands to
337 ensure a good working environment. It turns off echoing, it sets the
338 shell prompt, and a few other things.
341 Now the remote shell is up and it good working order. Remember, what
342 was supposed to happen is that @value{tramp} tries to find out what files exist
343 on the remote host so that it can do filename completion.
345 So, @value{tramp} basically issues @command{cd} and @command{ls} commands and
346 also sometimes @command{echo} with globbing. Another command that is
347 often used is @command{test} to find out whether a file is writable or a
348 directory or the like. The output of each command is parsed for the
352 Suppose you are finished with filename completion, have entered @kbd{C-x
353 C-f}, a full file name and hit @kbd{@key{RET}}. Now comes the time to
354 transfer the file contents from the remote host to the local host so
355 that you can edit them.
357 See above for an explanation of how @value{tramp} transfers the file contents.
359 For inline transfers, @value{tramp} issues a command like @samp{mimencode -b
360 /path/to/remote/file}, waits until the output has accumulated in the
361 buffer that's used for communication, then decodes that output to
362 produce the file contents.
364 For external transfers, @value{tramp} issues a command like the
367 rcp user@@host:/path/to/remote/file /tmp/tramp.4711
369 It then reads the local temporary file @file{/tmp/tramp.4711} into a
370 buffer and deletes the temporary file.
373 You now edit the buffer contents, blithely unaware of what has happened
374 behind the scenes. (Unless you have read this section, that is.) When
375 you are finished, you type @kbd{C-x C-s} to save the buffer.
378 Again, @value{tramp} transfers the file contents to the remote host
379 either inline or external. This is the reverse of what happens when
383 I hope this has provided you with a basic overview of what happens
384 behind the scenes when you open a file with @value{tramp}.
388 @node Obtaining Tramp
389 @chapter Obtaining Tramp.
390 @cindex obtaining Tramp
392 @value{tramp} is freely available on the Internet and the latest
393 release may be downloaded from
394 @uref{ftp://ftp.gnu.org/gnu/tramp/}. This release includes the full
395 documentation and code for @value{tramp}, suitable for installation.
396 But GNU Emacs (22 or later) includes @value{tramp} already, and there
397 is a @value{tramp} package for XEmacs, as well. So maybe it is easier
398 to just use those. But if you want the bleeding edge, read
401 For the especially brave, @value{tramp} is available from CVS. The CVS
402 version is the latest version of the code and may contain incomplete
403 features or new issues. Use these versions at your own risk.
405 Instructions for obtaining the latest development version of @value{tramp}
406 from CVS can be found by going to the Savannah project page at the
407 following URL and then clicking on the CVS link in the navigation bar
411 @uref{http://savannah.gnu.org/projects/tramp/}
414 Or follow the example session below:
417 ] @strong{cd ~/@value{emacsdir}}
418 ] @strong{export CVS_RSH="ssh"}
419 ] @strong{cvs -z3 -d:ext:anoncvs@@savannah.gnu.org:/cvsroot/tramp co tramp}
423 You should now have a directory @file{~/@value{emacsdir}/tramp}
424 containing the latest version of @value{tramp}. You can fetch the latest
425 updates from the repository by issuing the command:
428 ] @strong{cd ~/@value{emacsdir}/tramp}
429 ] @strong{export CVS_RSH="ssh"}
430 ] @strong{cvs update -d}
434 Once you've got updated files from the CVS repository, you need to run
435 @command{autoconf} in order to get an up-to-date @file{configure}
439 ] @strong{cd ~/@value{emacsdir}/tramp}
443 People who have no direct CVS access (maybe because sitting behind a
444 blocking firewall), can try the
445 @uref{http://savannah.gnu.org/cvs-backup/tramp-sources.tar.gz, Nightly
446 CVS Tree Tarball} instead of.
450 @chapter History of @value{tramp}
452 @cindex development history
454 Development was started end of November 1998. The package was called
455 @file{rssh.el}, back then. It only provided one method to access a
456 file, using @command{ssh} to log in to a remote host and using
457 @command{scp} to transfer the file contents. After a while, the name
458 was changed to @file{rcp.el}, and now it's @value{tramp}. Along the way,
459 many more methods for getting a remote shell and for transferring the
460 file contents were added. Support for VC was added.
462 The most recent addition of major features were the multi-hop methods
463 added in April 2000 and the unification of @value{tramp} and Ange-FTP
464 filenames in July 2002. In July 2004, multi-hop methods have been
465 replaced by proxy hosts. Running commands on remote hosts was
466 introduced in December 2005.
468 Support of gateways exists since April 2007.
471 GVFS integration started in February 2009.
474 In December 2001, @value{tramp} has been added to the XEmacs package
475 repository. Being part of the GNU Emacs repository happened in June
476 2002, the first release including @value{tramp} was GNU Emacs 22.1.
478 @value{tramp} is also a GNU/Linux Debian package since February 2001.
481 @c Installation chapter is necessary only in case of standalone
482 @c installation. Text taken from trampinst.texi.
483 @ifset installchapter
484 @include trampinst.texi
488 @chapter Configuring @value{tramp} for use
489 @cindex configuration
491 @cindex default configuration
492 @value{tramp} is (normally) fully functional when it is initially
493 installed. It is initially configured to use the @command{scp}
494 program to connect to the remote host. So in the easiest case, you
495 just type @kbd{C-x C-f} and then enter the filename
496 @file{@trampfn{, user, machine, /path/to.file}}.
498 On some hosts, there are problems with opening a connection. These are
499 related to the behavior of the remote shell. See @xref{Remote shell
500 setup}, for details on this.
502 If you do not wish to use these commands to connect to the remote
503 host, you should change the default connection and transfer method
504 that @value{tramp} uses. There are several different methods that @value{tramp}
505 can use to connect to remote machines and transfer files
506 (@pxref{Connection types}).
508 If you don't know which method is right for you, see @xref{Default
513 * Connection types:: Types of connections made to remote machines.
514 * Inline methods:: Inline methods.
515 * External methods:: External methods.
517 * GVFS based methods:: GVFS based external methods.
520 * Gateway methods:: Gateway methods.
522 * Default Method:: Selecting a default method.
523 Here we also try to help those who
524 don't have the foggiest which method
526 * Default User:: Selecting a default user.
527 * Default Host:: Selecting a default host.
528 * Multi-hops:: Connecting to a remote host using multiple hops.
529 * Customizing Methods:: Using Non-Standard Methods.
530 * Customizing Completion:: Selecting config files for user/host name completion.
531 * Password handling:: Reusing passwords for several connections.
532 * Connection caching:: Reusing connection related information.
533 * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine.
534 * Remote shell setup:: Remote shell setup hints.
535 * Windows setup hints:: Issues with Cygwin ssh.
536 * Auto-save and Backup:: Auto-save and Backup.
540 @node Connection types
541 @section Types of connections made to remote machines.
542 @cindex connection types, overview
544 There are two basic types of transfer methods, each with its own
545 advantages and limitations. Both types of connection make use of a
546 remote shell access program such as @command{rsh}, @command{ssh} or
547 @command{telnet} to connect to the remote machine.
549 This connection is used to perform many of the operations that @value{tramp}
550 requires to make the remote file system transparently accessible from
551 the local machine. It is only when visiting files that the methods
554 @cindex inline methods
555 @cindex external methods
556 @cindex methods, inline
557 @cindex methods, external
558 Loading or saving a remote file requires that the content of the file
559 be transfered between the two machines. The content of the file can
560 be transfered using one of two methods: the @dfn{inline method} over
561 the same connection used to log in to the remote machine, or the
562 @dfn{external method} through another connection using a remote copy
563 program such as @command{rcp}, @command{scp} or @command{rsync}.
565 The performance of the external methods is generally better than that
566 of the inline methods, at least for large files. This is caused by
567 the need to encode and decode the data when transferring inline.
569 The one exception to this rule are the @command{scp} based transfer
570 methods. While these methods do see better performance when actually
571 transferring files, the overhead of the cryptographic negotiation at
572 startup may drown out the improvement in file transfer times.
574 External methods should be configured such a way that they don't
575 require a password (with @command{ssh-agent}, or such alike). Modern
576 @command{scp} implementations offer options to reuse existing
577 @command{ssh} connections, see method @command{scpc}. If it isn't
578 possible, you should consider @ref{Password handling}, otherwise you
579 will be prompted for a password every copy action.
583 @section Inline methods
584 @cindex inline methods
585 @cindex methods, inline
587 The inline methods in @value{tramp} are quite powerful and can work in
588 situations where you cannot use an external transfer program to connect.
589 Inline methods are the only methods that work when connecting to the
590 remote machine via telnet. (There are also strange inline methods which
591 allow you to transfer files between @emph{user identities} rather than
594 These methods depend on the existence of a suitable encoding and
595 decoding command on remote machine. Locally, @value{tramp} may be able to
596 use features of @value{emacsname} to decode and encode the files or
597 it may require access to external commands to perform that task.
601 @cindex base-64 encoding
602 @value{tramp} checks the availability and usability of commands like
603 @command{mimencode} (part of the @command{metamail} package) or
604 @command{uuencode} on the remote host. The first reliable command
605 will be used. The search path can be customized, see @ref{Remote
608 If both commands aren't available on the remote host, @value{tramp}
609 transfers a small piece of Perl code to the remote host, and tries to
610 apply it for encoding and decoding.
618 Connect to the remote host with @command{rsh}. Due to the unsecure
619 connection it is recommended for very local host topology only.
621 On operating systems which provide the command @command{remsh} instead
622 of @command{rsh}, you can use the method @option{remsh}. This is true
623 for HP-UX or Cray UNICOS, for example.
630 Connect to the remote host with @command{ssh}. This is identical to
631 the previous option except that the @command{ssh} package is used,
632 making the connection more secure.
634 There are also two variants, @option{ssh1} and @option{ssh2}, that
635 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
636 explicitly select whether you want to use the SSH protocol version 1
637 or 2 to connect to the remote host. (You can also specify in
638 @file{~/.ssh/config}, the SSH configuration file, which protocol
639 should be used, and use the regular @option{ssh} method.)
641 Two other variants, @option{ssh1_old} and @option{ssh2_old}, use the
642 @command{ssh1} and @command{ssh2} commands explicitly. If you don't
643 know what these are, you do not need these options.
645 All the methods based on @command{ssh} have an additional kludgy
646 feature: you can specify a host name which looks like @file{host#42}
647 (the real host name, then a hash sign, then a port number). This
648 means to connect to the given host but to also pass @code{-p 42} as
649 arguments to the @command{ssh} command.
652 @item @option{telnet}
653 @cindex method telnet
654 @cindex telnet method
656 Connect to the remote host with @command{telnet}. This is as unsecure
657 as the @option{rsh} method.
664 This method does not connect to a remote host at all, rather it uses
665 the @command{su} program to allow you to edit files as another user.
666 That means, the specified host name in the file name must be either
667 @samp{localhost} or the host name as returned by the function
668 @command{(system-name)}. For an exception of this rule see
676 This is similar to the @option{su} method, but it uses @command{sudo}
677 rather than @command{su} to become a different user.
679 Note that @command{sudo} must be configured to allow you to start a
680 shell as the user. It would be nice if it was sufficient if
681 @command{ls} and @command{mimencode} were allowed, but that is not
682 easy to implement, so I haven't got around to it, yet.
689 As you would expect, this is similar to @option{ssh}, only a little
690 different. Whereas @option{ssh} opens a normal interactive shell on
691 the remote host, this option uses @samp{ssh -t -t @var{host} -l
692 @var{user} /bin/sh} to open a connection. This is useful for users
693 where the normal login shell is set up to ask them a number of
694 questions when logging in. This procedure avoids these questions, and
695 just gives @value{tramp} a more-or-less `standard' login shell to work
698 Note that this procedure does not eliminate questions asked by
699 @command{ssh} itself. For example, @command{ssh} might ask ``Are you
700 sure you want to continue connecting?'' if the host key of the remote
701 host is not known. @value{tramp} does not know how to deal with such a
702 question (yet), therefore you will need to make sure that you can log
703 in without such questions.
705 This is also useful for Windows users where @command{ssh}, when
706 invoked from an @value{emacsname} buffer, tells them that it is not
707 allocating a pseudo tty. When this happens, the login shell is wont
708 to not print any shell prompt, which confuses @value{tramp} mightily.
709 For reasons unknown, some Windows ports for @command{ssh} require the
710 doubled @samp{-t} option.
712 This supports the @samp{-p} argument.
715 @item @option{krlogin}
716 @cindex method krlogin
717 @cindex krlogin method
718 @cindex Kerberos (with krlogin method)
720 This method is also similar to @option{ssh}. It only uses the
721 @command{krlogin -x} command to log in to the remote host.
728 This method is mostly interesting for Windows users using the PuTTY
729 implementation of SSH. It uses @samp{plink -ssh} to log in to the
732 This supports the @samp{-P} argument.
734 Additionally, the methods @option{plink1} and @option{plink2} are
735 provided, which call @samp{plink -1 -ssh} or @samp{plink -2 -ssh} in
736 order to use SSH protocol version 1 or 2 explicitly.
738 CCC: Do we have to connect to the remote host once from the command
739 line to accept the SSH key? Maybe this can be made automatic?
741 CCC: Say something about the first shell command failing. This might
742 be due to a wrong setting of @code{tramp-rsh-end-of-line}.
745 @item @option{plinkx}
746 @cindex method plinkx
747 @cindex plinkx method
749 Another method using PuTTY on Windows. Instead of host names, it
750 expects PuTTY session names, calling @samp{plink -load @var{session}
751 -t"}. User names are relevant only in case the corresponding session
752 hasn't defined a user name. Different port numbers must be defined in
760 This is an experimental implementation of the fish protocol, known from
761 the GNU Midnight Commander or the KDE Konqueror. @value{tramp} expects
762 the fish server implementation from the KDE kioslave. That means, the
763 file @file{~/.fishsrv.pl} is expected to reside on the remote host.
765 The implementation lacks good performance. The code is offered anyway,
766 maybe somebody can improve the performance.
771 @node External methods
772 @section External methods
773 @cindex methods, external
774 @cindex external methods
776 The external methods operate through multiple channels, using the
777 remote shell connection for many actions while delegating file
778 transfers to an external transfer utility.
780 This saves the overhead of encoding and decoding that multiplexing the
781 transfer through the one connection has with the inline methods.
783 Since external methods need their own overhead opening a new channel,
784 all files which are smaller than @var{tramp-copy-size-limit} are still
785 transferred with the corresponding inline method. It should provide a
786 fair trade-off between both approaches.
789 @item @option{rcp} --- @command{rsh} and @command{rcp}
792 @cindex rcp (with rcp method)
793 @cindex rsh (with rcp method)
795 This method uses the @command{rsh} and @command{rcp} commands to connect
796 to the remote machine and transfer files. This is probably the fastest
797 connection method available.
799 The alternative method @option{remcp} uses the @command{remsh} and
800 @command{rcp} commands. It should be applied on machines where
801 @command{remsh} is used instead of @command{rsh}.
804 @item @option{scp} --- @command{ssh} and @command{scp}
807 @cindex scp (with scp method)
808 @cindex ssh (with scp method)
810 Using @command{ssh} to connect to the remote host and @command{scp} to
811 transfer files between the machines is the best method for securely
812 connecting to a remote machine and accessing files.
814 The performance of this option is also quite good. It may be slower than
815 the inline methods when you often open and close small files however.
816 The cost of the cryptographic handshake at the start of an @command{scp}
817 session can begin to absorb the advantage that the lack of encoding and
820 There are also two variants, @option{scp1} and @option{scp2}, that
821 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
822 explicitly select whether you want to use the SSH protocol version 1
823 or 2 to connect to the remote host. (You can also specify in
824 @file{~/.ssh/config}, the SSH configuration file, which protocol
825 should be used, and use the regular @option{scp} method.)
827 Two other variants, @option{scp1_old} and @option{scp2_old}, use the
828 @command{ssh1} and @command{ssh2} commands explicitly. If you don't
829 know what these are, you do not need these options.
831 All the @command{ssh} based methods support the @samp{-p} feature
832 where you can specify a port number to connect to in the host name.
833 For example, the host name @file{host#42} tells @value{tramp} to
834 specify @samp{-p 42} in the argument list for @command{ssh}, and to
835 specify @samp{-P 42} in the argument list for @command{scp}.
838 @item @option{sftp} --- @command{ssh} and @command{sftp}
841 @cindex sftp (with sftp method)
842 @cindex ssh (with sftp method)
844 That is mostly the same method as @option{scp}, but using
845 @command{sftp} as transfer command. So the same remarks are valid.
847 This command does not work like @value{ftppackagename}, where
848 @command{ftp} is called interactively, and all commands are send from
849 within this session. Instead of, @command{ssh} is used for login.
851 This method supports the @samp{-p} argument.
854 @item @option{rsync} --- @command{ssh} and @command{rsync}
857 @cindex rsync (with rsync method)
858 @cindex ssh (with rsync method)
860 Using the @command{ssh} command to connect securely to the remote
861 machine and the @command{rsync} command to transfer files is almost
862 identical to the @option{scp} method.
864 While @command{rsync} performs much better than @command{scp} when
865 transferring files that exist on both hosts, this advantage is lost if
866 the file exists only on one side of the connection. A file can exists
867 on both the remote and local host, when you copy a file from/to a
868 remote host. When you just open a file from the remote host (or write
869 a file there), this is not the case, because on the local side
870 temporary files are used.
872 This method supports the @samp{-p} argument.
875 @item @option{scpx} --- @command{ssh} and @command{scp}
878 @cindex scp (with scpx method)
879 @cindex ssh (with scpx method)
881 As you would expect, this is similar to @option{scp}, only a little
882 different. Whereas @option{scp} opens a normal interactive shell on
883 the remote host, this option uses @samp{ssh -t -t @var{host} -l
884 @var{user} /bin/sh} to open a connection. This is useful for users
885 where the normal login shell is set up to ask them a number of
886 questions when logging in. This procedure avoids these questions, and
887 just gives @value{tramp} a more-or-less `standard' login shell to work
890 This is also useful for Windows users where @command{ssh}, when
891 invoked from an @value{emacsname} buffer, tells them that it is not
892 allocating a pseudo tty. When this happens, the login shell is wont
893 to not print any shell prompt, which confuses @value{tramp} mightily.
895 This method supports the @samp{-p} argument.
898 @item @option{scpc} --- @command{ssh} and @command{scp}
901 @cindex scp (with scpx method)
902 @cindex ssh (with scpx method)
904 Newer versions of @option{ssh} (for example OpenSSH 4) offer an option
905 @option{ControlMaster}. This allows @option{scp} to reuse an existing
906 @option{ssh} channel, which increases performance.
908 Before you use this method, you shall check whether your @option{ssh}
909 implementation does support this option. Try from the command line
912 ssh localhost -o ControlMaster=yes
915 This method supports the @samp{-p} argument.
918 @item @option{pscp} --- @command{plink} and @command{pscp}
921 @cindex pscp (with pscp method)
922 @cindex plink (with pscp method)
923 @cindex PuTTY (with pscp method)
925 This method is similar to @option{scp}, but it uses the
926 @command{plink} command to connect to the remote host, and it uses
927 @command{pscp} for transferring the files. These programs are part
928 of PuTTY, an SSH implementation for Windows.
930 This method supports the @samp{-P} argument.
933 @item @option{psftp} --- @command{plink} and @command{psftp}
936 @cindex psftp (with psftp method)
937 @cindex plink (with psftp method)
938 @cindex PuTTY (with psftp method)
940 As you would expect, this method is similar to @option{sftp}, but it
941 uses the @command{plink} command to connect to the remote host, and it
942 uses @command{psftp} for transferring the files. These programs are
943 part of PuTTY, an SSH implementation for Windows.
945 This method supports the @samp{-P} argument.
948 @item @option{fcp} --- @command{fsh} and @command{fcp}
951 @cindex fsh (with fcp method)
952 @cindex fcp (with fcp method)
954 This method is similar to @option{scp}, but it uses the @command{fsh}
955 command to connect to the remote host, and it uses @command{fcp} for
956 transferring the files. @command{fsh/fcp} are a front-end for
957 @command{ssh} which allow for reusing the same @command{ssh} session
958 for submitting several commands. This avoids the startup overhead of
959 @command{scp} (which has to establish a secure connection whenever it
960 is called). Note, however, that you can also use one of the inline
961 methods to achieve a similar effect.
963 This method uses the command @samp{fsh @var{host} -l @var{user}
964 /bin/sh -i} to establish the connection, it does not work to just say
965 @command{fsh @var{host} -l @var{user}}.
970 There is no inline method using @command{fsh} as the multiplexing
971 provided by the program is not very useful in our context. @value{tramp}
972 opens just one connection to the remote host and then keeps it open,
980 This is not a native @value{tramp} method. Instead of, it forwards all
981 requests to @value{ftppackagename}.
983 This works only for unified filenames, see @ref{Issues}.
987 @item @option{smb} --- @command{smbclient}
991 This is another not natural @value{tramp} method. It uses the
992 @command{smbclient} command on different Unices in order to connect to
993 an SMB server. An SMB server might be a Samba (or CIFS) server on
994 another UNIX host or, more interesting, a host running MS Windows. So
995 far, it is tested towards MS Windows NT, MS Windows 2000, and MS
998 The first directory in the localname must be a share name on the remote
999 host. Remember, that the @code{$} character in which default shares
1000 usually end, must be written @code{$$} due to environment variable
1001 substitution in file names. If no share name is given (i.e. remote
1002 directory @code{/}), all available shares are listed.
1004 Since authorization is done on share level, you will be prompted
1005 always for a password if you access another share on the same host.
1006 This can be suppressed by @ref{Password handling}.
1008 MS Windows uses for authorization both a user name and a domain name.
1009 Because of this, the @value{tramp} syntax has been extended: you can
1010 specify a user name which looks like @code{user%domain} (the real user
1011 name, then a percent sign, then the domain name). So, to connect to
1012 the machine @code{melancholia} as user @code{daniel} of the domain
1013 @code{BIZARRE}, and edit @file{.emacs} in the home directory (share
1014 @code{daniel$}) I would specify the filename @file{@trampfn{smb,
1015 daniel%BIZARRE, melancholia, /daniel$$/.emacs}}.
1017 Depending on the Windows domain configuration, a Windows user might be
1018 considered as domain user per default. In order to connect as local
1019 user, the WINS name of that machine must be given as domain name.
1020 Usually, it is the machine name in capital letters. In the example
1021 above, the local user @code{daniel} would be specified as
1022 @file{@trampfn{smb, daniel%MELANCHOLIA, melancholia, /daniel$$/.emacs}}.
1024 The domain name as well as the user name are optional. If no user
1025 name is specified at all, the anonymous user (without password
1026 prompting) is assumed. This is different from all other @value{tramp}
1027 methods, where in such a case the local user name is taken.
1029 The @option{smb} method supports the @samp{-p} argument.
1031 @strong{Please note:} If @value{emacsname} runs locally under MS
1032 Windows, this method isn't available. Instead of, you can use UNC
1033 file names like @file{//melancholia/daniel$$/.emacs}. The only
1034 disadvantage is that there's no possibility to specify another user
1040 @node GVFS based methods
1041 @section GVFS based external methods
1042 @cindex methods, gvfs
1043 @cindex gvfs based methods
1046 The connection methods described in this section are based on GVFS
1047 @uref{http://en.wikipedia.org/wiki/GVFS}. Via GVFS, the remote
1048 filesystem is mounted locally through FUSE. @value{tramp} uses
1049 internally this local mounted directory.
1051 The communication with GVFS is implemented via D-Bus messages.
1052 Therefore, your @value{emacsname} must have D-Bus integration,
1053 @pxref{Top, , D-Bus, dbus}.
1060 This method provides access to WebDAV files and directories. There
1061 exists also the external method @option{davs}, which uses SSL
1062 encryption for the access.
1064 Both methods support the port number specification as discussed above.
1070 OBEX is an FTP-like access protocol for simple devices, like cell
1071 phones. Until now @value{tramp} supports only OBEX over Bluetooth.
1073 @item @option{synce}
1074 @cindex method synce
1075 @cindex synce method
1077 The @option{synce} method allows communication with Windows Mobile
1078 devices. Beside GVFS for mounting remote files and directories via
1079 FUSE, it needs also the SYNCE-GVFS plugin.
1082 @defopt tramp-gvfs-methods
1083 This customer option, a list, defines the external methods, which
1084 shall be used with GVFS. Per default, these are @option{dav},
1085 @option{davs}, @option{obex} and @option{synce}. Other possible
1086 values are @option{ftp}, @option{sftp} and @option{smb}.
1092 @node Gateway methods
1093 @section Gateway methods
1094 @cindex methods, gateway
1095 @cindex gateway methods
1097 Gateway methods are not methods to access a remote host directly.
1098 These methods are intended to pass firewalls or proxy servers.
1099 Therefore, they can be used for proxy host declarations
1100 (@pxref{Multi-hops}) only.
1102 A gateway method must come always along with a method who supports
1103 port setting. This is because @value{tramp} targets the accompanied
1104 method to @file{localhost#random_port}, from where the firewall or
1105 proxy server is accessed to.
1107 Gateway methods support user name and password declarations. These
1108 are used to authenticate towards the corresponding firewall or proxy
1109 server. They can be passed only if your friendly administrator has
1110 granted your access.
1113 @item @option{tunnel}
1114 @cindex method tunnel
1115 @cindex tunnel method
1117 This method implements an HTTP tunnel via the @command{CONNECT}
1118 command (see RFC 2616, 2817). Any HTTP 1.1 compliant (proxy) server
1119 shall support this command.
1121 As authentication method, only @option{Basic Authentication} (see RFC
1122 2617) is implemented so far. If no port number is given in the
1123 declaration, port @option{8080} is used for the proxy server.
1126 @item @option{socks}
1127 @cindex method socks
1128 @cindex socks method
1130 The @command{socks} method provides access to SOCKSv5 servers (see
1131 RFC 1928). @option{Username/Password Authentication} according to RFC
1134 The default port number of the socks server is @option{1080}, if not
1135 specified otherwise.
1141 @node Default Method
1142 @section Selecting a default method
1143 @cindex default method
1145 @vindex tramp-default-method
1146 When you select an appropriate transfer method for your typical usage
1147 you should set the variable @code{tramp-default-method} to reflect that
1148 choice. This variable controls which method will be used when a method
1149 is not specified in the @value{tramp} file name. For example:
1152 (setq tramp-default-method "ssh")
1155 @vindex tramp-default-method-alist
1156 You can also specify different methods for certain user/host
1157 combinations, via the variable @code{tramp-default-method-alist}. For
1158 example, the following two lines specify to use the @option{ssh}
1159 method for all user names matching @samp{john} and the @option{rsync}
1160 method for all host names matching @samp{lily}. The third line
1161 specifies to use the @option{su} method for the user @samp{root} on
1162 the machine @samp{localhost}.
1165 (add-to-list 'tramp-default-method-alist '("" "john" "ssh"))
1166 (add-to-list 'tramp-default-method-alist '("lily" "" "rsync"))
1167 (add-to-list 'tramp-default-method-alist
1168 '("\\`localhost\\'" "\\`root\\'" "su"))
1172 See the documentation for the variable
1173 @code{tramp-default-method-alist} for more details.
1175 External methods are normally preferable to inline methods, giving
1178 @xref{Inline methods}.
1179 @xref{External methods}.
1181 Another consideration with the selection of transfer methods is the
1182 environment you will use them in and, especially when used over the
1183 Internet, the security implications of your preferred method.
1185 The @option{rsh} and @option{telnet} methods send your password as
1186 plain text as you log in to the remote machine, as well as
1187 transferring the files in such a way that the content can easily be
1188 read from other machines.
1190 If you need to connect to remote systems that are accessible from the
1191 Internet, you should give serious thought to using @option{ssh} based
1192 methods to connect. These provide a much higher level of security,
1193 making it a non-trivial exercise for someone to obtain your password
1194 or read the content of the files you are editing.
1197 @subsection Which method is the right one for me?
1198 @cindex choosing the right method
1200 Given all of the above, you are probably thinking that this is all fine
1201 and good, but it's not helping you to choose a method! Right you are.
1202 As a developer, we don't want to boss our users around but give them
1203 maximum freedom instead. However, the reality is that some users would
1204 like to have some guidance, so here I'll try to give you this guidance
1205 without bossing you around. You tell me whether it works @dots{}
1207 My suggestion is to use an inline method. For large files, external
1208 methods might be more efficient, but I guess that most people will
1209 want to edit mostly small files.
1211 I guess that these days, most people can access a remote machine by
1212 using @command{ssh}. So I suggest that you use the @option{ssh}
1213 method. So, type @kbd{C-x C-f @trampfn{ssh, root, otherhost,
1214 /etc/motd} @key{RET}} to edit the @file{/etc/motd} file on the other
1217 If you can't use @option{ssh} to log in to the remote host, then
1218 select a method that uses a program that works. For instance, Windows
1219 users might like the @option{plink} method which uses the PuTTY
1220 implementation of @command{ssh}. Or you use Kerberos and thus like
1223 For the special case of editing files on the local host as another
1224 user, see the @option{su} or @option{sudo} methods. They offer
1225 shortened syntax for the @samp{root} account, like
1226 @file{@trampfn{su, , , /etc/motd}}.
1228 People who edit large files may want to consider @option{scpc} instead
1229 of @option{ssh}, or @option{pscp} instead of @option{plink}. These
1230 external methods are faster than inline methods for large files.
1231 Note, however, that external methods suffer from some limitations.
1232 Please try first whether you really get a noticeable speed advantage
1233 from using an external method! Maybe even for large files, inline
1234 methods are fast enough.
1238 @section Selecting a default user
1239 @cindex default user
1241 The user part of a @value{tramp} file name can be omitted. Usually,
1242 it is replaced by the user name you are logged in. Often, this is not
1243 what you want. A typical use of @value{tramp} might be to edit some
1244 files with root permissions on the local host. This case, you should
1245 set the variable @code{tramp-default-user} to reflect that choice.
1249 (setq tramp-default-user "root")
1252 @code{tramp-default-user} is regarded as obsolete, and will be removed
1255 @vindex tramp-default-user-alist
1256 You can also specify different users for certain method/host
1257 combinations, via the variable @code{tramp-default-user-alist}. For
1258 example, if you always have to use the user @samp{john} in the domain
1259 @samp{somewhere.else}, you can specify the following:
1262 (add-to-list 'tramp-default-user-alist
1263 '("ssh" ".*\\.somewhere\\.else\\'" "john"))
1267 See the documentation for the variable
1268 @code{tramp-default-user-alist} for more details.
1270 One trap to fall in must be known. If @value{tramp} finds a default
1271 user, this user will be passed always to the connection command as
1272 parameter (for example @samp{ssh here.somewhere.else -l john}. If you
1273 have specified another user for your command in its configuration
1274 files, @value{tramp} cannot know it, and the remote access will fail.
1275 If you have specified in the given example in @file{~/.ssh/config} the
1279 Host here.somewhere.else
1284 than you must discard selecting a default user by @value{tramp}. This
1285 will be done by setting it to @code{nil} (or @samp{lily}, likewise):
1288 (add-to-list 'tramp-default-user-alist
1289 '("ssh" "\\`here\\.somewhere\\.else\\'" nil))
1292 The last entry in @code{tramp-default-user-alist} could be your
1293 default user you'll apply predominantly. You shall @emph{append} it
1294 to that list at the end:
1297 (add-to-list 'tramp-default-user-alist '(nil nil "jonas") t)
1302 @section Selecting a default host
1303 @cindex default host
1305 @vindex tramp-default-host
1306 Finally, it is even possible to omit the host name part of a
1307 @value{tramp} file name. This case, the value of the variable
1308 @code{tramp-default-host} is used. Per default, it is initialized
1309 with the host name your local @value{emacsname} is running.
1311 If you, for example, use @value{tramp} mainly to contact the host
1312 @samp{target} as user @samp{john}, you can specify:
1315 (setq tramp-default-user "john"
1316 tramp-default-host "target")
1319 Then the simple file name @samp{@trampfn{ssh, , ,}} will connect you
1320 to John's home directory on target.
1322 Note, however, that the most simplification @samp{/::} won't work,
1323 because @samp{/:} is the prefix for quoted file names.
1328 @section Connecting to a remote host using multiple hops
1332 Sometimes, the methods described before are not sufficient. Sometimes,
1333 it is not possible to connect to a remote host using a simple command.
1334 For example, if you are in a secured network, you might have to log in
1335 to a `bastion host' first before you can connect to the outside world.
1336 Of course, the target host may also require a bastion host.
1338 @vindex tramp-default-proxies-alist
1339 In order to specify such multiple hops, it is possible to define a proxy
1340 host to pass through, via the variable
1341 @code{tramp-default-proxies-alist}. This variable keeps a list of
1342 triples (@var{host} @var{user} @var{proxy}).
1344 The first matching item specifies the proxy host to be passed for a
1345 file name located on a remote target matching @var{user}@@@var{host}.
1346 @var{host} and @var{user} are regular expressions or @code{nil}, which
1347 is interpreted as a regular expression which always matches.
1349 @var{proxy} must be a Tramp filename which localname part is ignored.
1350 Method and user name on @var{proxy} are optional, which is interpreted
1351 with the default values.
1353 The method must be an inline or gateway method (@pxref{Inline
1354 methods}, @pxref{Gateway methods}).
1357 The method must be an inline method (@pxref{Inline methods}).
1359 If @var{proxy} is @code{nil}, no additional hop is required reaching
1360 @var{user}@@@var{host}.
1362 If you, for example, must pass the host @samp{bastion.your.domain} as
1363 user @samp{bird} for any remote host which is not located in your local
1367 (add-to-list 'tramp-default-proxies-alist
1368 '("\\." nil "@trampfn{ssh, bird, bastion.your.domain,}"))
1369 (add-to-list 'tramp-default-proxies-alist
1370 '("\\.your\\.domain\\'" nil nil))
1373 Please note the order of the code. @code{add-to-list} adds elements at the
1374 beginning of a list. Therefore, most relevant rules must be added last.
1376 Proxy hosts can be cascaded. If there is another host called
1377 @samp{jump.your.domain}, which is the only one in your local domain who
1378 is allowed connecting @samp{bastion.your.domain}, you can add another
1382 (add-to-list 'tramp-default-proxies-alist
1383 '("\\`bastion\\.your\\.domain\\'"
1385 "@trampfn{ssh, , jump.your.domain,}"))
1388 @var{proxy} can contain the patterns @code{%h} or @code{%u}. These
1389 patterns are replaced by the strings matching @var{host} or
1390 @var{user}, respectively.
1392 If you, for example, wants to work as @samp{root} on hosts in the
1393 domain @samp{your.domain}, but login as @samp{root} is disabled for
1394 non-local access, you might add the following rule:
1397 (add-to-list 'tramp-default-proxies-alist
1398 '("\\.your\\.domain\\'" "\\`root\\'" "@trampfn{ssh, , %h,}"))
1401 Opening @file{@trampfn{sudo, , randomhost.your.domain,}} would connect
1402 first @samp{randomhost.your.domain} via @code{ssh} under your account
1403 name, and perform @code{sudo -u root} on that host afterwards. It is
1404 important to know that the given method is applied on the host which
1405 has been reached so far. @code{sudo -u root}, applied on your local
1406 host, wouldn't be useful here.
1408 @var{host}, @var{user} and @var{proxy} can also be Lisp forms. These
1409 forms are evaluated, and must return a string, or @code{nil}. The
1410 previous example could be generalized then: For all hosts except my
1411 local one connect via @code{ssh} first, and apply @code{sudo -u root}
1415 (add-to-list 'tramp-default-proxies-alist
1416 '(nil "\\`root\\'" "@trampfn{ssh, , %h,}"))
1417 (add-to-list 'tramp-default-proxies-alist
1418 '((regexp-quote (system-name)) nil nil))
1421 This is the recommended configuration to work as @samp{root} on remote
1425 Finally, @code{tramp-default-proxies-alist} can be used to pass
1426 firewalls or proxy servers. Imagine your local network has a host
1427 @samp{proxy.your.domain} which is used on port 3128 as HTTP proxy to
1428 the outer world. Your friendly administrator has granted you access
1429 under your user name to @samp{host.other.domain} on that proxy
1430 server.@footnote{HTTP tunnels are intended for secure SSL/TLS
1431 communication. Therefore, many proxy server restrict the tunnels to
1432 related target ports. You might need to run your ssh server on your
1433 target host @samp{host.other.domain} on such a port, like 443 (https).
1434 See @uref{http://savannah.gnu.org/maintenance/CvsFromBehindFirewall}
1435 for discussion of ethical issues.} You would need to add the
1439 (add-to-list 'tramp-default-proxies-alist
1440 '("\\`host\\.other\\.domain\\'" nil
1441 "@trampfn{tunnel, , proxy.your.domain#3128,}"))
1444 Gateway methods can be declared as first hop only in a multiple hop
1449 @node Customizing Methods
1450 @section Using Non-Standard Methods
1451 @cindex customizing methods
1452 @cindex using non-standard methods
1453 @cindex create your own methods
1455 There is a variable @code{tramp-methods} which you can change if the
1456 predefined methods don't seem right.
1458 For the time being, I'll refer you to the Lisp documentation of that
1459 variable, accessible with @kbd{C-h v tramp-methods @key{RET}}.
1462 @node Customizing Completion
1463 @section Selecting config files for user/host name completion
1464 @cindex customizing completion
1465 @cindex selecting config files
1466 @vindex tramp-completion-function-alist
1468 The variable @code{tramp-completion-function-alist} is intended to
1469 customize which files are taken into account for user and host name
1470 completion (@pxref{Filename completion}). For every method, it keeps
1471 a set of configuration files, accompanied by a Lisp function able to
1472 parse that file. Entries in @code{tramp-completion-function-alist}
1473 have the form (@var{method} @var{pair1} @var{pair2} ...).
1475 Each @var{pair} is composed of (@var{function} @var{file}).
1476 @var{function} is responsible to extract user names and host names
1477 from @var{file} for completion. There are two functions which access
1480 @defun tramp-get-completion-function method
1481 This function returns the list of completion functions for @var{method}.
1485 (tramp-get-completion-function "rsh")
1487 @result{} ((tramp-parse-rhosts "/etc/hosts.equiv")
1488 (tramp-parse-rhosts "~/.rhosts"))
1492 @defun tramp-set-completion-function method function-list
1493 This function sets @var{function-list} as list of completion functions
1498 (tramp-set-completion-function "ssh"
1499 '((tramp-parse-sconfig "/etc/ssh_config")
1500 (tramp-parse-sconfig "~/.ssh/config")))
1502 @result{} ((tramp-parse-sconfig "/etc/ssh_config")
1503 (tramp-parse-sconfig "~/.ssh/config"))
1507 The following predefined functions parsing configuration files exist:
1510 @item @code{tramp-parse-rhosts}
1511 @findex tramp-parse-rhosts
1513 This function parses files which are syntactical equivalent to
1514 @file{~/.rhosts}. It returns both host names and user names, if
1517 @item @code{tramp-parse-shosts}
1518 @findex tramp-parse-shosts
1520 This function parses files which are syntactical equivalent to
1521 @file{~/.ssh/known_hosts}. Since there are no user names specified
1522 in such files, it can return host names only.
1524 @item @code{tramp-parse-sconfig}
1525 @findex tramp-parse-shosts
1527 This function returns the host nicknames defined by @code{Host} entries
1528 in @file{~/.ssh/config} style files.
1530 @item @code{tramp-parse-shostkeys}
1531 @findex tramp-parse-shostkeys
1533 SSH2 parsing of directories @file{/etc/ssh2/hostkeys/*} and
1534 @file{~/ssh2/hostkeys/*}. Hosts are coded in file names
1535 @file{hostkey_@var{portnumber}_@var{host-name}.pub}. User names
1536 are always @code{nil}.
1538 @item @code{tramp-parse-sknownhosts}
1539 @findex tramp-parse-shostkeys
1541 Another SSH2 style parsing of directories like
1542 @file{/etc/ssh2/knownhosts/*} and @file{~/ssh2/knownhosts/*}. This
1543 case, hosts names are coded in file names
1544 @file{@var{host-name}.@var{algorithm}.pub}. User names are always @code{nil}.
1546 @item @code{tramp-parse-hosts}
1547 @findex tramp-parse-hosts
1549 A function dedicated to @file{/etc/hosts} style files. It returns
1552 @item @code{tramp-parse-passwd}
1553 @findex tramp-parse-passwd
1555 A function which parses @file{/etc/passwd} like files. Obviously, it
1556 can return user names only.
1558 @item @code{tramp-parse-netrc}
1559 @findex tramp-parse-netrc
1561 Finally, a function which parses @file{~/.netrc} like files.
1564 If you want to keep your own data in a file, with your own structure,
1565 you might provide such a function as well. This function must meet
1566 the following conventions:
1568 @defun my-tramp-parse file
1569 @var{file} must be either a file name on your host, or @code{nil}.
1570 The function must return a list of (@var{user} @var{host}), which are
1571 taken as candidates for user and host name completion.
1575 (my-tramp-parse "~/.my-tramp-hosts")
1577 @result{} ((nil "toto") ("daniel" "melancholia"))
1582 @node Password handling
1583 @section Reusing passwords for several connections.
1586 Sometimes it is necessary to connect to the same remote host several
1587 times. Reentering passwords again and again would be annoying, when
1588 the chosen method does not support access without password prompt
1589 through own configuration.
1591 The best recommendation is to use the method's own mechanism for
1592 password handling. Consider @command{ssh-agent} for @option{ssh}-like
1593 methods, or @command{pageant} for @option{plink}-like methods.
1595 However, if you cannot apply such native password handling,
1596 @value{tramp} offers altenatives.
1599 @anchor{auth-sources}
1600 @subsection Using an authentication file
1602 @vindex auth-sources
1603 The package @file{auth-source.el}, originally developed in No Gnus,
1604 offers the possibility to read passwords from a file, like FTP does it
1605 from @file{~/.netrc}. The default authentication file is
1606 @file{~/.authinfo.gpg}, this can be changed via the variable
1607 @code{auth-sources}.
1610 A typical entry in the authentication file would be
1613 machine melancholia port scp login daniel password geheim
1616 The port can be any @value{tramp} method (@pxref{Inline methods},
1617 @pxref{External methods}), to match only this method. When you omit
1618 the port, you match all @value{tramp} methods.
1621 @anchor{password-cache}
1622 @subsection Caching passwords
1624 If there is no authentication file, @value{tramp} caches the passwords
1625 entered by you. They will be reused next time if a connection needs
1626 them for the same user name and host name, independently of the
1629 @vindex password-cache-expiry
1630 Passwords are not saved permanently, that means the password caching
1631 is limited to the lifetime of your @value{emacsname} session. You
1632 can influence the lifetime of password caching by customizing the
1633 variable @code{password-cache-expiry}. The value is the number of
1634 seconds how long passwords are cached. Setting it to @code{nil}
1635 disables the expiration.
1637 @vindex password-cache
1638 If you don't like this feature for security reasons, password caching
1639 can be disabled totally by customizing the variable
1640 @code{password-cache} (setting it to @code{nil}).
1642 Implementation Note: password caching is based on the package
1643 @file{password-cache.el}. For the time being, it is activated only
1644 when this package is seen in the @code{load-path} while loading
1646 @ifset installchapter
1647 If you don't use No Gnus, you can take @file{password.el} from the
1648 @value{tramp} @file{contrib} directory, see @ref{Installation
1653 @node Connection caching
1654 @section Reusing connection related information.
1657 @vindex tramp-persistency-file-name
1658 In order to reduce initial connection time, @value{tramp} stores
1659 connection related information persistently. The variable
1660 @code{tramp-persistency-file-name} keeps the file name where these
1661 information are written. Its default value is
1663 @file{~/.emacs.d/tramp}.
1666 @file{~/.xemacs/tramp}.
1668 It is recommended to choose a local file name.
1670 @value{tramp} reads this file during startup, and writes it when
1671 exiting @value{emacsname}. You can simply remove this file if
1672 @value{tramp} shall be urged to recompute these information next
1673 @value{emacsname} startup time.
1675 Using such persistent information can be disabled by setting
1676 @code{tramp-persistency-file-name} to @code{nil}.
1678 Once consequence of reusing connection related information is that
1679 @var{tramp} needs to distinguish hosts. If you, for example, run a
1680 local @code{sshd} on port 3001, which tunnels @command{ssh} to another
1681 host, you could access both @file{@trampfn{ssh, , localhost,}} and
1682 @file{@trampfn{ssh, , localhost#3001,}}. @var{tramp} would use the
1683 same host related information (like paths, Perl variants, etc) for
1684 both connections, although the information is valid only for one of
1687 In order to avoid trouble, you must use another host name for one of
1688 the connections, like introducing a @option{Host} section in
1689 @file{~/.ssh/config} (@pxref{Frequently Asked Questions}) or applying
1690 multiple hops (@pxref{Multi-hops}).
1692 When @value{tramp} detects a changed operating system version on a
1693 remote host (via the command @command{uname -sr}), it flushes all
1694 connection related information for this host, and opens the
1698 @node Remote Programs
1699 @section How @value{tramp} finds and uses programs on the remote machine.
1701 @value{tramp} depends on a number of programs on the remote host in order to
1702 function, including @command{ls}, @command{test}, @command{find} and
1705 In addition to these required tools, there are various tools that may be
1706 required based on the connection method. See @ref{Inline methods} and
1707 @ref{External methods} for details on these.
1709 Certain other tools, such as @command{perl} (or @command{perl5}) and
1710 @command{grep} will be used if they can be found. When they are
1711 available, they are used to improve the performance and accuracy of
1714 @vindex tramp-remote-path
1715 @vindex tramp-default-remote-path
1716 @vindex tramp-own-remote-path
1717 @defopt tramp-remote-path
1718 When @value{tramp} connects to the remote machine, it searches for the
1719 programs that it can use. The variable @code{tramp-remote-path}
1720 controls the directories searched on the remote machine.
1722 By default, this is set to a reasonable set of defaults for most
1723 machines. The symbol @code{tramp-default-remote-path} is a place
1724 holder, it is replaced by the list of directories received via the
1725 command @command{getconf PATH} on your remote machine. For example,
1726 on GNU Debian this is @file{/bin:/usr/bin}, whereas on Solaris this is
1727 @file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin}. It is
1728 recommended to apply this symbol on top of @code{tramp-remote-path}.
1730 It is possible, however, that your local (or remote ;) system
1731 administrator has put the tools you want in some obscure local
1734 In this case, you can still use them with @value{tramp}. You simply
1735 need to add code to your @file{.emacs} to add the directory to the
1736 remote path. This will then be searched by @value{tramp} when you
1737 connect and the software found.
1739 To add a directory to the remote search path, you could use code such
1743 @i{;; We load @value{tramp} to define the variable.}
1745 @i{;; We have @command{perl} in "/usr/local/perl/bin"}
1746 (add-to-list 'tramp-remote-path "/usr/local/perl/bin")
1749 Another possibility is to reuse the path settings of your remote
1750 account, when you log in. Usually, these settings are overwritten,
1751 because they might not be useful for @value{tramp}. The place holder
1752 @code{tramp-own-remote-path} preserves these settings. You can
1756 (add-to-list 'tramp-remote-path 'tramp-own-remote-path)
1760 @value{tramp} caches several information, like the Perl binary
1761 location. The changed remote search path wouldn't affect these
1762 settings. In order to force @value{tramp} to recompute these values,
1763 you must exit @value{emacsname}, remove your persistency file
1764 (@pxref{Connection caching}), and restart @value{emacsname}.
1767 @node Remote shell setup
1768 @section Remote shell setup hints
1769 @cindex remote shell setup
1770 @cindex @file{.profile} file
1771 @cindex @file{.login} file
1772 @cindex shell init files
1774 As explained in the @ref{Overview} section, @value{tramp} connects to the
1775 remote host and talks to the shell it finds there. Of course, when you
1776 log in, the shell executes its init files. Suppose your init file
1777 requires you to enter the birth date of your mother; clearly @value{tramp}
1778 does not know this and hence fails to log you in to that host.
1780 There are different possible strategies for pursuing this problem. One
1781 strategy is to enable @value{tramp} to deal with all possible situations.
1782 This is a losing battle, since it is not possible to deal with
1783 @emph{all} situations. The other strategy is to require you to set up
1784 the remote host such that it behaves like @value{tramp} expects. This might
1785 be inconvenient because you have to invest a lot of effort into shell
1786 setup before you can begin to use @value{tramp}.
1788 The package, therefore, pursues a combined approach. It tries to
1789 figure out some of the more common setups, and only requires you to
1790 avoid really exotic stuff. For example, it looks through a list of
1791 directories to find some programs on the remote host. And also, it
1792 knows that it is not obvious how to check whether a file exists, and
1793 therefore it tries different possibilities. (On some hosts and
1794 shells, the command @command{test -e} does the trick, on some hosts
1795 the shell builtin doesn't work but the program @command{/usr/bin/test
1796 -e} or @command{/bin/test -e} works. And on still other hosts,
1797 @command{ls -d} is the right way to do this.)
1799 Below you find a discussion of a few things that @value{tramp} does not deal
1800 with, and that you therefore have to set up correctly.
1803 @item @var{shell-prompt-pattern}
1804 @vindex shell-prompt-pattern
1806 After logging in to the remote host, @value{tramp} has to wait for the remote
1807 shell startup to finish before it can send commands to the remote
1808 shell. The strategy here is to wait for the shell prompt. In order to
1809 recognize the shell prompt, the variable @code{shell-prompt-pattern} has
1810 to be set correctly to recognize the shell prompt on the remote host.
1812 Note that @value{tramp} requires the match for @code{shell-prompt-pattern}
1813 to be at the end of the buffer. Many people have something like the
1814 following as the value for the variable: @code{"^[^>$][>$] *"}. Now
1815 suppose your shell prompt is @code{a <b> c $ }. In this case,
1816 @value{tramp} recognizes the @code{>} character as the end of the prompt,
1817 but it is not at the end of the buffer.
1819 @item @var{tramp-shell-prompt-pattern}
1820 @vindex tramp-shell-prompt-pattern
1822 This regular expression is used by @value{tramp} in the same way as
1823 @code{shell-prompt-pattern}, to match prompts from the remote shell.
1824 This second variable exists because the prompt from the remote shell
1825 might be different from the prompt from a local shell --- after all,
1826 the whole point of @value{tramp} is to log in to remote hosts as a
1827 different user. The default value of
1828 @code{tramp-shell-prompt-pattern} is the same as the default value of
1829 @code{shell-prompt-pattern}, which is reported to work well in many
1832 @item @var{tramp-password-prompt-regexp}
1833 @vindex tramp-password-prompt-regexp
1834 @vindex tramp-wrong-passwd-regexp
1836 During login, @value{tramp} might be forced to enter a password or a
1837 passphrase. The difference between both is that a password is
1838 requested from the shell on the remote host, while a passphrase is
1839 needed for accessing local authentication information, like your ssh
1842 @var{tramp-password-prompt-regexp} handles the detection of such
1843 requests for English environments. When you use another localization
1844 of your (local or remote) host, you might need to adapt this. Example:
1848 tramp-password-prompt-regexp
1852 '("passphrase" "Passphrase"
1854 "password" "Password"
1856 "passwort" "Passwort"
1858 "mot de passe" "Mot de passe") t)