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, 2010 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 * 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
380 @uref{ftp://ftp.gnu.org/gnu/tramp/}. This release includes the full
381 documentation and code for @value{tramp}, suitable for installation.
382 But GNU Emacs (22 or later) includes @value{tramp} already, and there
383 is a @value{tramp} package for XEmacs, as well. So maybe it is easier
384 to just use those. But if you want the bleeding edge, read
387 For the especially brave, @value{tramp} is available from CVS. The CVS
388 version is the latest version of the code and may contain incomplete
389 features or new issues. Use these versions at your own risk.
391 Instructions for obtaining the latest development version of @value{tramp}
392 from CVS can be found by going to the Savannah project page at the
393 following URL and then clicking on the CVS link in the navigation bar
397 @uref{http://savannah.gnu.org/projects/tramp/}
400 Or follow the example session below:
403 ] @strong{cd ~/@value{emacsdir}}
404 ] @strong{export CVS_RSH="ssh"}
405 ] @strong{cvs -z3 -d:pserver:anonymous@@cvs.savannah.gnu.org:/sources/tramp co tramp}
409 You should now have a directory @file{~/@value{emacsdir}/tramp}
410 containing the latest version of @value{tramp}. You can fetch the latest
411 updates from the repository by issuing the command:
414 ] @strong{cd ~/@value{emacsdir}/tramp}
415 ] @strong{export CVS_RSH="ssh"}
416 ] @strong{cvs update -d}
420 Once you've got updated files from the CVS repository, you need to run
421 @command{autoconf} in order to get an up-to-date @file{configure}
425 ] @strong{cd ~/@value{emacsdir}/tramp}
431 @chapter History of @value{tramp}
433 @cindex development history
435 Development was started end of November 1998. The package was called
436 @file{rssh.el}, back then. It only provided one method to access a
437 file, using @command{ssh} to log in to a remote host and using
438 @command{scp} to transfer the file contents. After a while, the name
439 was changed to @file{rcp.el}, and now it's @value{tramp}. Along the way,
440 many more methods for getting a remote shell and for transferring the
441 file contents were added. Support for VC was added.
443 After that, there were added the multi-hop methods in April 2000 and
444 the unification of @value{tramp} and Ange-FTP filenames in July 2002.
445 In July 2004, multi-hop methods have been replaced by proxy hosts.
446 Running commands on remote hosts was introduced in December 2005.
448 Support of gateways exists since April 2007.
451 GVFS integration started in February 2009.
454 Storing files into IMAP mailboxes has been added in September 2009.
457 In December 2001, @value{tramp} has been added to the XEmacs package
458 repository. Being part of the GNU Emacs repository happened in June
459 2002, the first release including @value{tramp} was GNU Emacs 22.1.
461 @value{tramp} is also a GNU/Linux Debian package since February 2001.
464 @c Installation chapter is necessary only in case of standalone
465 @c installation. Text taken from trampinst.texi.
466 @ifset installchapter
467 @include trampinst.texi
471 @chapter Configuring @value{tramp} for use
472 @cindex configuration
474 @cindex default configuration
475 @value{tramp} is (normally) fully functional when it is initially
476 installed. It is initially configured to use the @command{scp}
477 program to connect to the remote host. So in the easiest case, you
478 just type @kbd{C-x C-f} and then enter the filename
479 @file{@trampfn{, user, machine, /path/to.file}}.
481 On some hosts, there are problems with opening a connection. These are
482 related to the behavior of the remote shell. See @xref{Remote shell
483 setup}, for details on this.
485 If you do not wish to use these commands to connect to the remote
486 host, you should change the default connection and transfer method
487 that @value{tramp} uses. There are several different methods that @value{tramp}
488 can use to connect to remote machines and transfer files
489 (@pxref{Connection types}).
491 If you don't know which method is right for you, see @xref{Default
496 * Connection types:: Types of connections made to remote machines.
497 * Inline methods:: Inline methods.
498 * External methods:: External methods.
500 * GVFS based methods:: GVFS based external methods.
503 * Gateway methods:: Gateway methods.
505 * Default Method:: Selecting a default method.
506 Here we also try to help those who
507 don't have the foggiest which method
509 * Default User:: Selecting a default user.
510 * Default Host:: Selecting a default host.
511 * Multi-hops:: Connecting to a remote host using multiple hops.
512 * Customizing Methods:: Using Non-Standard Methods.
513 * Customizing Completion:: Selecting config files for user/host name completion.
514 * Password handling:: Reusing passwords for several connections.
515 * Connection caching:: Reusing connection related information.
516 * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine.
517 * Remote shell setup:: Remote shell setup hints.
518 * Windows setup hints:: Issues with Cygwin ssh.
519 * Auto-save and Backup:: Auto-save and Backup.
523 @node Connection types
524 @section Types of connections made to remote machines.
525 @cindex connection types, overview
527 There are two basic types of transfer methods, each with its own
528 advantages and limitations. Both types of connection make use of a
529 remote shell access program such as @command{rsh}, @command{ssh} or
530 @command{telnet} to connect to the remote machine.
532 This connection is used to perform many of the operations that @value{tramp}
533 requires to make the remote file system transparently accessible from
534 the local machine. It is only when visiting files that the methods
537 @cindex inline methods
538 @cindex external methods
539 @cindex methods, inline
540 @cindex methods, external
541 Loading or saving a remote file requires that the content of the file
542 be transfered between the two machines. The content of the file can
543 be transfered using one of two methods: the @dfn{inline method} over
544 the same connection used to log in to the remote machine, or the
545 @dfn{external method} through another connection using a remote copy
546 program such as @command{rcp}, @command{scp} or @command{rsync}.
548 The performance of the external methods is generally better than that
549 of the inline methods, at least for large files. This is caused by
550 the need to encode and decode the data when transferring inline.
552 The one exception to this rule are the @command{scp} based transfer
553 methods. While these methods do see better performance when actually
554 transferring files, the overhead of the cryptographic negotiation at
555 startup may drown out the improvement in file transfer times.
557 External methods should be configured such a way that they don't
558 require a password (with @command{ssh-agent}, or such alike). Modern
559 @command{scp} implementations offer options to reuse existing
560 @command{ssh} connections, see method @command{scpc}. If it isn't
561 possible, you should consider @ref{Password handling}, otherwise you
562 will be prompted for a password every copy action.
566 @section Inline methods
567 @cindex inline methods
568 @cindex methods, inline
570 The inline methods in @value{tramp} are quite powerful and can work in
571 situations where you cannot use an external transfer program to connect.
572 Inline methods are the only methods that work when connecting to the
573 remote machine via telnet. (There are also strange inline methods which
574 allow you to transfer files between @emph{user identities} rather than
577 These methods depend on the existence of a suitable encoding and
578 decoding command on remote machine. Locally, @value{tramp} may be able to
579 use features of @value{emacsname} to decode and encode the files or
580 it may require access to external commands to perform that task.
584 @cindex base-64 encoding
585 @value{tramp} checks the availability and usability of commands like
586 @command{mimencode} (part of the @command{metamail} package) or
587 @command{uuencode} on the remote host. The first reliable command
588 will be used. The search path can be customized, see @ref{Remote
591 If both commands aren't available on the remote host, @value{tramp}
592 transfers a small piece of Perl code to the remote host, and tries to
593 apply it for encoding and decoding.
595 The variable @var{tramp-inline-compress-start-size} controls, whether
596 a file shall be compressed before encoding. This could increase
597 transfer speed for large text files.
605 Connect to the remote host with @command{rsh}. Due to the unsecure
606 connection it is recommended for very local host topology only.
608 On operating systems which provide the command @command{remsh} instead
609 of @command{rsh}, you can use the method @option{remsh}. This is true
610 for HP-UX or Cray UNICOS, for example.
617 Connect to the remote host with @command{ssh}. This is identical to
618 the previous option except that the @command{ssh} package is used,
619 making the connection more secure.
621 There are also two variants, @option{ssh1} and @option{ssh2}, that
622 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
623 explicitly select whether you want to use the SSH protocol version 1
624 or 2 to connect to the remote host. (You can also specify in
625 @file{~/.ssh/config}, the SSH configuration file, which protocol
626 should be used, and use the regular @option{ssh} method.)
628 Two other variants, @option{ssh1_old} and @option{ssh2_old}, use the
629 @command{ssh1} and @command{ssh2} commands explicitly. If you don't
630 know what these are, you do not need these options.
632 All the methods based on @command{ssh} have an additional kludgy
633 feature: you can specify a host name which looks like @file{host#42}
634 (the real host name, then a hash sign, then a port number). This
635 means to connect to the given host but to also pass @code{-p 42} as
636 arguments to the @command{ssh} command.
639 @item @option{telnet}
640 @cindex method telnet
641 @cindex telnet method
643 Connect to the remote host with @command{telnet}. This is as unsecure
644 as the @option{rsh} method.
651 This method does not connect to a remote host at all, rather it uses
652 the @command{su} program to allow you to edit files as another user.
653 That means, the specified host name in the file name must be either
654 @samp{localhost} or the host name as returned by the function
655 @command{(system-name)}. For an exception of this rule see
663 This is similar to the @option{su} method, but it uses @command{sudo}
664 rather than @command{su} to become a different user.
666 Note that @command{sudo} must be configured to allow you to start a
667 shell as the user. It would be nice if it was sufficient if
668 @command{ls} and @command{mimencode} were allowed, but that is not
669 easy to implement, so I haven't got around to it, yet.
676 As you would expect, this is similar to @option{ssh}, only a little
677 different. Whereas @option{ssh} opens a normal interactive shell on
678 the remote host, this option uses @samp{ssh -t -t @var{host} -l
679 @var{user} /bin/sh} to open a connection. This is useful for users
680 where the normal login shell is set up to ask them a number of
681 questions when logging in. This procedure avoids these questions, and
682 just gives @value{tramp} a more-or-less `standard' login shell to work
685 Note that this procedure does not eliminate questions asked by
686 @command{ssh} itself. For example, @command{ssh} might ask ``Are you
687 sure you want to continue connecting?'' if the host key of the remote
688 host is not known. @value{tramp} does not know how to deal with such a
689 question (yet), therefore you will need to make sure that you can log
690 in without such questions.
692 This is also useful for Windows users where @command{ssh}, when
693 invoked from an @value{emacsname} buffer, tells them that it is not
694 allocating a pseudo tty. When this happens, the login shell is wont
695 to not print any shell prompt, which confuses @value{tramp} mightily.
696 For reasons unknown, some Windows ports for @command{ssh} require the
697 doubled @samp{-t} option.
699 This supports the @samp{-p} argument.
702 @item @option{krlogin}
703 @cindex method krlogin
704 @cindex krlogin method
705 @cindex Kerberos (with krlogin method)
707 This method is also similar to @option{ssh}. It only uses the
708 @command{krlogin -x} command to log in to the remote host.
715 This method is mostly interesting for Windows users using the PuTTY
716 implementation of SSH. It uses @samp{plink -ssh} to log in to the
719 This supports the @samp{-P} argument.
721 Additionally, the methods @option{plink1} and @option{plink2} are
722 provided, which call @samp{plink -1 -ssh} or @samp{plink -2 -ssh} in
723 order to use SSH protocol version 1 or 2 explicitly.
725 CCC: Do we have to connect to the remote host once from the command
726 line to accept the SSH key? Maybe this can be made automatic?
728 CCC: Say something about the first shell command failing. This might
729 be due to a wrong setting of @code{tramp-rsh-end-of-line}.
732 @item @option{plinkx}
733 @cindex method plinkx
734 @cindex plinkx method
736 Another method using PuTTY on Windows. Instead of host names, it
737 expects PuTTY session names, calling @samp{plink -load @var{session}
738 -t"}. User names are relevant only in case the corresponding session
739 hasn't defined a user name. Different port numbers must be defined in
747 This is an experimental implementation of the fish protocol, known from
748 the GNU Midnight Commander or the KDE Konqueror. @value{tramp} expects
749 the fish server implementation from the KDE kioslave. That means, the
750 file @file{~/.fishsrv.pl} is expected to reside on the remote host.
752 The implementation lacks good performance. The code is offered anyway,
753 maybe somebody can improve the performance.
758 @node External methods
759 @section External methods
760 @cindex methods, external
761 @cindex external methods
763 The external methods operate through multiple channels, using the
764 remote shell connection for many actions while delegating file
765 transfers to an external transfer utility.
767 This saves the overhead of encoding and decoding that multiplexing the
768 transfer through the one connection has with the inline methods.
770 Since external methods need their own overhead opening a new channel,
771 all files which are smaller than @var{tramp-copy-size-limit} are still
772 transferred with the corresponding inline method. It should provide a
773 fair trade-off between both approaches.
776 @item @option{rcp} --- @command{rsh} and @command{rcp}
779 @cindex rcp (with rcp method)
780 @cindex rsh (with rcp method)
782 This method uses the @command{rsh} and @command{rcp} commands to connect
783 to the remote machine and transfer files. This is probably the fastest
784 connection method available.
786 The alternative method @option{remcp} uses the @command{remsh} and
787 @command{rcp} commands. It should be applied on machines where
788 @command{remsh} is used instead of @command{rsh}.
791 @item @option{scp} --- @command{ssh} and @command{scp}
794 @cindex scp (with scp method)
795 @cindex ssh (with scp method)
797 Using @command{ssh} to connect to the remote host and @command{scp} to
798 transfer files between the machines is the best method for securely
799 connecting to a remote machine and accessing files.
801 The performance of this option is also quite good. It may be slower than
802 the inline methods when you often open and close small files however.
803 The cost of the cryptographic handshake at the start of an @command{scp}
804 session can begin to absorb the advantage that the lack of encoding and
807 There are also two variants, @option{scp1} and @option{scp2}, that
808 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
809 explicitly select whether you want to use the SSH protocol version 1
810 or 2 to connect to the remote host. (You can also specify in
811 @file{~/.ssh/config}, the SSH configuration file, which protocol
812 should be used, and use the regular @option{scp} method.)
814 Two other variants, @option{scp1_old} and @option{scp2_old}, use the
815 @command{ssh1} and @command{ssh2} commands explicitly. If you don't
816 know what these are, you do not need these options.
818 All the @command{ssh} based methods support the @samp{-p} feature
819 where you can specify a port number to connect to in the host name.
820 For example, the host name @file{host#42} tells @value{tramp} to
821 specify @samp{-p 42} in the argument list for @command{ssh}, and to
822 specify @samp{-P 42} in the argument list for @command{scp}.
825 @item @option{sftp} --- @command{ssh} and @command{sftp}
828 @cindex sftp (with sftp method)
829 @cindex ssh (with sftp method)
831 That is mostly the same method as @option{scp}, but using
832 @command{sftp} as transfer command. So the same remarks are valid.
834 This command does not work like @value{ftppackagename}, where
835 @command{ftp} is called interactively, and all commands are send from
836 within this session. Instead of, @command{ssh} is used for login.
838 This method supports the @samp{-p} argument.
841 @item @option{rsync} --- @command{ssh} and @command{rsync}
844 @cindex rsync (with rsync method)
845 @cindex ssh (with rsync method)
847 Using the @command{ssh} command to connect securely to the remote
848 machine and the @command{rsync} command to transfer files is almost
849 identical to the @option{scp} method.
851 While @command{rsync} performs much better than @command{scp} when
852 transferring files that exist on both hosts, this advantage is lost if
853 the file exists only on one side of the connection. A file can exists
854 on both the remote and local host, when you copy a file from/to a
855 remote host. When you just open a file from the remote host (or write
856 a file there), a temporary file on the local side is kept as long as
857 the corresponding buffer, visiting this file, is alive.
859 This method supports the @samp{-p} argument.
862 @item @option{scpx} --- @command{ssh} and @command{scp}
865 @cindex scp (with scpx method)
866 @cindex ssh (with scpx method)
868 As you would expect, this is similar to @option{scp}, only a little
869 different. Whereas @option{scp} opens a normal interactive shell on
870 the remote host, this option uses @samp{ssh -t -t @var{host} -l
871 @var{user} /bin/sh} to open a connection. This is useful for users
872 where the normal login shell is set up to ask them a number of
873 questions when logging in. This procedure avoids these questions, and
874 just gives @value{tramp} a more-or-less `standard' login shell to work
877 This is also useful for Windows users where @command{ssh}, when
878 invoked from an @value{emacsname} buffer, tells them that it is not
879 allocating a pseudo tty. When this happens, the login shell is wont
880 to not print any shell prompt, which confuses @value{tramp} mightily.
882 This method supports the @samp{-p} argument.
885 @item @option{scpc} --- @command{ssh} and @command{scp}
888 @cindex scp (with scpc method)
889 @cindex ssh (with scpc method)
891 Newer versions of @option{ssh} (for example OpenSSH 4) offer an option
892 @option{ControlMaster}. This allows @option{scp} to reuse an existing
893 @option{ssh} channel, which increases performance.
895 Before you use this method, you shall check whether your @option{ssh}
896 implementation does support this option. Try from the command line
899 ssh localhost -o ControlMaster=yes
902 This method supports the @samp{-p} argument.
905 @item @option{rsyncc} --- @command{ssh} and @command{rsync}
906 @cindex method rsyncc
907 @cindex rsyncc method
908 @cindex rsync (with rsyncc method)
909 @cindex ssh (with rsyncc method)
911 Like the @option{scpc} method, @option{rsyncc} improves the underlying
912 @command{ssh} connection by the option @option{ControlMaster}. This
913 allows @command{rsync} to reuse an existing @command{ssh} channel,
914 which increases performance.
916 This method supports the @samp{-p} argument.
919 @item @option{pscp} --- @command{plink} and @command{pscp}
922 @cindex pscp (with pscp method)
923 @cindex plink (with pscp method)
924 @cindex PuTTY (with pscp method)
926 This method is similar to @option{scp}, but it uses the
927 @command{plink} command to connect to the remote host, and it uses
928 @command{pscp} for transferring the files. These programs are part
929 of PuTTY, an SSH implementation for Windows.
931 This method supports the @samp{-P} argument.
934 @item @option{psftp} --- @command{plink} and @command{psftp}
937 @cindex psftp (with psftp method)
938 @cindex plink (with psftp method)
939 @cindex PuTTY (with psftp method)
941 As you would expect, this method is similar to @option{sftp}, but it
942 uses the @command{plink} command to connect to the remote host, and it
943 uses @command{psftp} for transferring the files. These programs are
944 part of PuTTY, an SSH implementation for Windows.
946 This method supports the @samp{-P} argument.
949 @item @option{fcp} --- @command{fsh} and @command{fcp}
952 @cindex fsh (with fcp method)
953 @cindex fcp (with fcp method)
955 This method is similar to @option{scp}, but it uses the @command{fsh}
956 command to connect to the remote host, and it uses @command{fcp} for
957 transferring the files. @command{fsh/fcp} are a front-end for
958 @command{ssh} which allow for reusing the same @command{ssh} session
959 for submitting several commands. This avoids the startup overhead of
960 @command{scp} (which has to establish a secure connection whenever it
961 is called). Note, however, that you can also use one of the inline
962 methods to achieve a similar effect.
964 This method uses the command @samp{fsh @var{host} -l @var{user}
965 /bin/sh -i} to establish the connection, it does not work to just say
966 @command{fsh @var{host} -l @var{user}}.
971 There is no inline method using @command{fsh} as the multiplexing
972 provided by the program is not very useful in our context. @value{tramp}
973 opens just one connection to the remote host and then keeps it open,
981 This is not a native @value{tramp} method. Instead of, it forwards all
982 requests to @value{ftppackagename}.
984 This works only for unified filenames, see @ref{Issues}.
988 @item @option{smb} --- @command{smbclient}
992 This is another not natural @value{tramp} method. It uses the
993 @command{smbclient} command on different Unices in order to connect to
994 an SMB server. An SMB server might be a Samba (or CIFS) server on
995 another UNIX host or, more interesting, a host running MS Windows. So
996 far, it is tested towards MS Windows NT, MS Windows 2000, and MS
999 The first directory in the localname must be a share name on the remote
1000 host. Remember, that the @code{$} character in which default shares
1001 usually end, must be written @code{$$} due to environment variable
1002 substitution in file names. If no share name is given (i.e. remote
1003 directory @code{/}), all available shares are listed.
1005 Since authorization is done on share level, you will be prompted
1006 always for a password if you access another share on the same host.
1007 This can be suppressed by @ref{Password handling}.
1009 MS Windows uses for authorization both a user name and a domain name.
1010 Because of this, the @value{tramp} syntax has been extended: you can
1011 specify a user name which looks like @code{user%domain} (the real user
1012 name, then a percent sign, then the domain name). So, to connect to
1013 the machine @code{melancholia} as user @code{daniel} of the domain
1014 @code{BIZARRE}, and edit @file{.emacs} in the home directory (share
1015 @code{daniel$}) I would specify the filename @file{@trampfn{smb,
1016 daniel%BIZARRE, melancholia, /daniel$$/.emacs}}.
1018 Depending on the Windows domain configuration, a Windows user might be
1019 considered as domain user per default. In order to connect as local
1020 user, the WINS name of that machine must be given as domain name.
1021 Usually, it is the machine name in capital letters. In the example
1022 above, the local user @code{daniel} would be specified as
1023 @file{@trampfn{smb, daniel%MELANCHOLIA, melancholia, /daniel$$/.emacs}}.
1025 The domain name as well as the user name are optional. If no user
1026 name is specified at all, the anonymous user (without password
1027 prompting) is assumed. This is different from all other @value{tramp}
1028 methods, where in such a case the local user name is taken.
1030 The @option{smb} method supports the @samp{-p} argument.
1032 @strong{Please note:} If @value{emacsname} runs locally under MS
1033 Windows, this method isn't available. Instead of, you can use UNC
1034 file names like @file{//melancholia/daniel$$/.emacs}. The only
1035 disadvantage is that there's no possibility to specify another user
1042 @cindex method imaps
1044 @cindex imaps method
1046 Accessing an IMAP mailbox is intended to save files there as encrypted
1047 message. It could be used in case there are no other remote file
1050 @value{tramp} supports both @option{imap} and @option{imaps} methods.
1051 The latter one accesses the IMAP server over ssl.
1053 Both methods support the port number specification.
1055 Note, that special handling is needed for declaring a passphrase for
1056 encryption / decryption of the messages (@pxref{Using an
1057 authentication file}).
1064 @node GVFS based methods
1065 @section GVFS based external methods
1066 @cindex methods, gvfs
1067 @cindex gvfs based methods
1070 The connection methods described in this section are based on GVFS
1071 @uref{http://en.wikipedia.org/wiki/GVFS}. Via GVFS, the remote
1072 filesystem is mounted locally through FUSE. @value{tramp} uses
1073 internally this local mounted directory.
1075 The communication with GVFS is implemented via D-Bus messages.
1076 Therefore, your @value{emacsname} must have D-Bus integration,
1077 @pxref{Top, , D-Bus, dbus}.
1086 This method provides access to WebDAV files and directories. There
1087 exists also the external method @option{davs}, which uses SSL
1088 encryption for the access.
1090 Both methods support the port number specification as discussed above.
1097 OBEX is an FTP-like access protocol for simple devices, like cell
1098 phones. Until now @value{tramp} supports only OBEX over Bluetooth.
1101 @item @option{synce}
1102 @cindex method synce
1103 @cindex synce method
1105 The @option{synce} method allows communication with Windows Mobile
1106 devices. Beside GVFS for mounting remote files and directories via
1107 FUSE, it needs also the SYNCE-GVFS plugin.
1110 @defopt tramp-gvfs-methods
1111 This customer option, a list, defines the external methods, which
1112 shall be used with GVFS. Per default, these are @option{dav},
1113 @option{davs}, @option{obex} and @option{synce}. Other possible
1114 values are @option{ftp}, @option{sftp} and @option{smb}.
1120 @node Gateway methods
1121 @section Gateway methods
1122 @cindex methods, gateway
1123 @cindex gateway methods
1125 Gateway methods are not methods to access a remote host directly.
1126 These methods are intended to pass firewalls or proxy servers.
1127 Therefore, they can be used for proxy host declarations
1128 (@pxref{Multi-hops}) only.
1130 A gateway method must come always along with a method who supports
1131 port setting. This is because @value{tramp} targets the accompanied
1132 method to @file{localhost#random_port}, from where the firewall or
1133 proxy server is accessed to.
1135 Gateway methods support user name and password declarations. These
1136 are used to authenticate towards the corresponding firewall or proxy
1137 server. They can be passed only if your friendly administrator has
1138 granted your access.
1141 @item @option{tunnel}
1142 @cindex method tunnel
1143 @cindex tunnel method
1145 This method implements an HTTP tunnel via the @command{CONNECT}
1146 command (see RFC 2616, 2817). Any HTTP 1.1 compliant (proxy) server
1147 shall support this command.
1149 As authentication method, only @option{Basic Authentication} (see RFC
1150 2617) is implemented so far. If no port number is given in the
1151 declaration, port @option{8080} is used for the proxy server.
1154 @item @option{socks}
1155 @cindex method socks
1156 @cindex socks method
1158 The @command{socks} method provides access to SOCKSv5 servers (see
1159 RFC 1928). @option{Username/Password Authentication} according to RFC
1162 The default port number of the socks server is @option{1080}, if not
1163 specified otherwise.
1169 @node Default Method
1170 @section Selecting a default method
1171 @cindex default method
1173 @vindex tramp-default-method
1174 When you select an appropriate transfer method for your typical usage
1175 you should set the variable @code{tramp-default-method} to reflect that
1176 choice. This variable controls which method will be used when a method
1177 is not specified in the @value{tramp} file name. For example:
1180 (setq tramp-default-method "ssh")
1183 @vindex tramp-default-method-alist
1184 You can also specify different methods for certain user/host
1185 combinations, via the variable @code{tramp-default-method-alist}. For
1186 example, the following two lines specify to use the @option{ssh}
1187 method for all user names matching @samp{john} and the @option{rsync}
1188 method for all host names matching @samp{lily}. The third line
1189 specifies to use the @option{su} method for the user @samp{root} on
1190 the machine @samp{localhost}.
1193 (add-to-list 'tramp-default-method-alist '("" "john" "ssh"))
1194 (add-to-list 'tramp-default-method-alist '("lily" "" "rsync"))
1195 (add-to-list 'tramp-default-method-alist
1196 '("\\`localhost\\'" "\\`root\\'" "su"))
1200 See the documentation for the variable
1201 @code{tramp-default-method-alist} for more details.
1203 External methods are normally preferable to inline methods, giving
1206 @xref{Inline methods}.
1207 @xref{External methods}.
1209 Another consideration with the selection of transfer methods is the
1210 environment you will use them in and, especially when used over the
1211 Internet, the security implications of your preferred method.
1213 The @option{rsh} and @option{telnet} methods send your password as
1214 plain text as you log in to the remote machine, as well as
1215 transferring the files in such a way that the content can easily be
1216 read from other machines.
1218 If you need to connect to remote systems that are accessible from the
1219 Internet, you should give serious thought to using @option{ssh} based
1220 methods to connect. These provide a much higher level of security,
1221 making it a non-trivial exercise for someone to obtain your password
1222 or read the content of the files you are editing.
1225 @subsection Which method is the right one for me?
1226 @cindex choosing the right method
1228 Given all of the above, you are probably thinking that this is all fine
1229 and good, but it's not helping you to choose a method! Right you are.
1230 As a developer, we don't want to boss our users around but give them
1231 maximum freedom instead. However, the reality is that some users would
1232 like to have some guidance, so here I'll try to give you this guidance
1233 without bossing you around. You tell me whether it works @dots{}
1235 My suggestion is to use an inline method. For large files, external
1236 methods might be more efficient, but I guess that most people will
1237 want to edit mostly small files. And if you access large text files,
1238 compression (driven by @var{tramp-inline-compress-start-size}) shall
1239 still result in good performance.
1241 I guess that these days, most people can access a remote machine by
1242 using @command{ssh}. So I suggest that you use the @option{ssh}
1243 method. So, type @kbd{C-x C-f @trampfn{ssh, root, otherhost,
1244 /etc/motd} @key{RET}} to edit the @file{/etc/motd} file on the other
1247 If you can't use @option{ssh} to log in to the remote host, then
1248 select a method that uses a program that works. For instance, Windows
1249 users might like the @option{plink} method which uses the PuTTY
1250 implementation of @command{ssh}. Or you use Kerberos and thus like
1253 For the special case of editing files on the local host as another
1254 user, see the @option{su} or @option{sudo} methods. They offer
1255 shortened syntax for the @samp{root} account, like
1256 @file{@trampfn{su, , , /etc/motd}}.
1258 People who edit large files may want to consider @option{scpc} instead
1259 of @option{ssh}, or @option{pscp} instead of @option{plink}. These
1260 external methods are faster than inline methods for large files.
1261 Note, however, that external methods suffer from some limitations.
1262 Please try first whether you really get a noticeable speed advantage
1263 from using an external method! Maybe even for large files, inline
1264 methods are fast enough.
1268 @section Selecting a default user
1269 @cindex default user
1271 The user part of a @value{tramp} file name can be omitted. Usually,
1272 it is replaced by the user name you are logged in. Often, this is not
1273 what you want. A typical use of @value{tramp} might be to edit some
1274 files with root permissions on the local host. This case, you should
1275 set the variable @code{tramp-default-user} to reflect that choice.
1279 (setq tramp-default-user "root")
1282 @code{tramp-default-user} is regarded as obsolete, and will be removed
1285 @vindex tramp-default-user-alist
1286 You can also specify different users for certain method/host
1287 combinations, via the variable @code{tramp-default-user-alist}. For
1288 example, if you always have to use the user @samp{john} in the domain
1289 @samp{somewhere.else}, you can specify the following:
1292 (add-to-list 'tramp-default-user-alist
1293 '("ssh" ".*\\.somewhere\\.else\\'" "john"))
1297 See the documentation for the variable
1298 @code{tramp-default-user-alist} for more details.
1300 One trap to fall in must be known. If @value{tramp} finds a default
1301 user, this user will be passed always to the connection command as
1302 parameter (for example @samp{ssh here.somewhere.else -l john}. If you
1303 have specified another user for your command in its configuration
1304 files, @value{tramp} cannot know it, and the remote access will fail.
1305 If you have specified in the given example in @file{~/.ssh/config} the
1309 Host here.somewhere.else
1314 than you must discard selecting a default user by @value{tramp}. This
1315 will be done by setting it to @code{nil} (or @samp{lily}, likewise):
1318 (add-to-list 'tramp-default-user-alist
1319 '("ssh" "\\`here\\.somewhere\\.else\\'" nil))
1322 The last entry in @code{tramp-default-user-alist} could be your
1323 default user you'll apply predominantly. You shall @emph{append} it
1324 to that list at the end:
1327 (add-to-list 'tramp-default-user-alist '(nil nil "jonas") t)
1332 @section Selecting a default host
1333 @cindex default host
1335 @vindex tramp-default-host
1336 Finally, it is even possible to omit the host name part of a
1337 @value{tramp} file name. This case, the value of the variable
1338 @code{tramp-default-host} is used. Per default, it is initialized
1339 with the host name your local @value{emacsname} is running.
1341 If you, for example, use @value{tramp} mainly to contact the host
1342 @samp{target} as user @samp{john}, you can specify:
1345 (setq tramp-default-user "john"
1346 tramp-default-host "target")
1349 Then the simple file name @samp{@trampfn{ssh, , ,}} will connect you
1350 to John's home directory on target.
1352 Note, however, that the most simplification @samp{/::} won't work,
1353 because @samp{/:} is the prefix for quoted file names.
1358 @section Connecting to a remote host using multiple hops
1362 Sometimes, the methods described before are not sufficient. Sometimes,
1363 it is not possible to connect to a remote host using a simple command.
1364 For example, if you are in a secured network, you might have to log in
1365 to a `bastion host' first before you can connect to the outside world.
1366 Of course, the target host may also require a bastion host.
1368 @vindex tramp-default-proxies-alist
1369 In order to specify such multiple hops, it is possible to define a proxy
1370 host to pass through, via the variable
1371 @code{tramp-default-proxies-alist}. This variable keeps a list of
1372 triples (@var{host} @var{user} @var{proxy}).
1374 The first matching item specifies the proxy host to be passed for a
1375 file name located on a remote target matching @var{user}@@@var{host}.
1376 @var{host} and @var{user} are regular expressions or @code{nil}, which
1377 is interpreted as a regular expression which always matches.
1379 @var{proxy} must be a Tramp filename which localname part is ignored.
1380 Method and user name on @var{proxy} are optional, which is interpreted
1381 with the default values.
1383 The method must be an inline or gateway method (@pxref{Inline
1384 methods}, @pxref{Gateway methods}).
1387 The method must be an inline method (@pxref{Inline methods}).
1389 If @var{proxy} is @code{nil}, no additional hop is required reaching
1390 @var{user}@@@var{host}.
1392 If you, for example, must pass the host @samp{bastion.your.domain} as
1393 user @samp{bird} for any remote host which is not located in your local
1397 (add-to-list 'tramp-default-proxies-alist
1398 '("\\." nil "@trampfn{ssh, bird, bastion.your.domain,}"))
1399 (add-to-list 'tramp-default-proxies-alist
1400 '("\\.your\\.domain\\'" nil nil))
1403 Please note the order of the code. @code{add-to-list} adds elements at the
1404 beginning of a list. Therefore, most relevant rules must be added last.
1406 Proxy hosts can be cascaded. If there is another host called
1407 @samp{jump.your.domain}, which is the only one in your local domain who
1408 is allowed connecting @samp{bastion.your.domain}, you can add another
1412 (add-to-list 'tramp-default-proxies-alist
1413 '("\\`bastion\\.your\\.domain\\'"
1415 "@trampfn{ssh, , jump.your.domain,}"))
1418 @var{proxy} can contain the patterns @code{%h} or @code{%u}. These
1419 patterns are replaced by the strings matching @var{host} or
1420 @var{user}, respectively.
1422 If you, for example, wants to work as @samp{root} on hosts in the
1423 domain @samp{your.domain}, but login as @samp{root} is disabled for
1424 non-local access, you might add the following rule:
1427 (add-to-list 'tramp-default-proxies-alist
1428 '("\\.your\\.domain\\'" "\\`root\\'" "@trampfn{ssh, , %h,}"))
1431 Opening @file{@trampfn{sudo, , randomhost.your.domain,}} would connect
1432 first @samp{randomhost.your.domain} via @code{ssh} under your account
1433 name, and perform @code{sudo -u root} on that host afterwards. It is
1434 important to know that the given method is applied on the host which
1435 has been reached so far. @code{sudo -u root}, applied on your local
1436 host, wouldn't be useful here.
1438 @var{host}, @var{user} and @var{proxy} can also be Lisp forms. These
1439 forms are evaluated, and must return a string, or @code{nil}. The
1440 previous example could be generalized then: For all hosts except my
1441 local one connect via @code{ssh} first, and apply @code{sudo -u root}
1445 (add-to-list 'tramp-default-proxies-alist
1446 '(nil "\\`root\\'" "@trampfn{ssh, , %h,}"))
1447 (add-to-list 'tramp-default-proxies-alist
1448 '((regexp-quote (system-name)) nil nil))
1451 This is the recommended configuration to work as @samp{root} on remote
1455 Finally, @code{tramp-default-proxies-alist} can be used to pass
1456 firewalls or proxy servers. Imagine your local network has a host
1457 @samp{proxy.your.domain} which is used on port 3128 as HTTP proxy to
1458 the outer world. Your friendly administrator has granted you access
1459 under your user name to @samp{host.other.domain} on that proxy
1460 server.@footnote{HTTP tunnels are intended for secure SSL/TLS
1461 communication. Therefore, many proxy server restrict the tunnels to
1462 related target ports. You might need to run your ssh server on your
1463 target host @samp{host.other.domain} on such a port, like 443 (https).
1464 See @uref{http://savannah.gnu.org/maintenance/CvsFromBehindFirewall}
1465 for discussion of ethical issues.} You would need to add the
1469 (add-to-list 'tramp-default-proxies-alist
1470 '("\\`host\\.other\\.domain\\'" nil
1471 "@trampfn{tunnel, , proxy.your.domain#3128,}"))
1474 Gateway methods can be declared as first hop only in a multiple hop
1479 @node Customizing Methods
1480 @section Using Non-Standard Methods
1481 @cindex customizing methods
1482 @cindex using non-standard methods
1483 @cindex create your own methods
1485 There is a variable @code{tramp-methods} which you can change if the
1486 predefined methods don't seem right.
1488 For the time being, I'll refer you to the Lisp documentation of that
1489 variable, accessible with @kbd{C-h v tramp-methods @key{RET}}.
1492 @node Customizing Completion
1493 @section Selecting config files for user/host name completion
1494 @cindex customizing completion
1495 @cindex selecting config files
1496 @vindex tramp-completion-function-alist
1498 The variable @code{tramp-completion-function-alist} is intended to
1499 customize which files are taken into account for user and host name
1500 completion (@pxref{Filename completion}). For every method, it keeps
1501 a set of configuration files, accompanied by a Lisp function able to
1502 parse that file. Entries in @code{tramp-completion-function-alist}
1503 have the form (@var{method} @var{pair1} @var{pair2} ...).
1505 Each @var{pair} is composed of (@var{function} @var{file}).
1506 @var{function} is responsible to extract user names and host names
1507 from @var{file} for completion. There are two functions which access
1510 @defun tramp-get-completion-function method
1511 This function returns the list of completion functions for @var{method}.
1515 (tramp-get-completion-function "rsh")
1517 @result{} ((tramp-parse-rhosts "/etc/hosts.equiv")
1518 (tramp-parse-rhosts "~/.rhosts"))
1522 @defun tramp-set-completion-function method function-list
1523 This function sets @var{function-list} as list of completion functions
1528 (tramp-set-completion-function "ssh"
1529 '((tramp-parse-sconfig "/etc/ssh_config")
1530 (tramp-parse-sconfig "~/.ssh/config")))
1532 @result{} ((tramp-parse-sconfig "/etc/ssh_config")
1533 (tramp-parse-sconfig "~/.ssh/config"))
1537 The following predefined functions parsing configuration files exist:
1540 @item @code{tramp-parse-rhosts}
1541 @findex tramp-parse-rhosts
1543 This function parses files which are syntactical equivalent to
1544 @file{~/.rhosts}. It returns both host names and user names, if
1547 @item @code{tramp-parse-shosts}
1548 @findex tramp-parse-shosts
1550 This function parses files which are syntactical equivalent to
1551 @file{~/.ssh/known_hosts}. Since there are no user names specified
1552 in such files, it can return host names only.
1554 @item @code{tramp-parse-sconfig}
1555 @findex tramp-parse-shosts
1557 This function returns the host nicknames defined by @code{Host} entries
1558 in @file{~/.ssh/config} style files.
1560 @item @code{tramp-parse-shostkeys}
1561 @findex tramp-parse-shostkeys
1563 SSH2 parsing of directories @file{/etc/ssh2/hostkeys/*} and
1564 @file{~/ssh2/hostkeys/*}. Hosts are coded in file names
1565 @file{hostkey_@var{portnumber}_@var{host-name}.pub}. User names
1566 are always @code{nil}.
1568 @item @code{tramp-parse-sknownhosts}
1569 @findex tramp-parse-shostkeys
1571 Another SSH2 style parsing of directories like
1572 @file{/etc/ssh2/knownhosts/*} and @file{~/ssh2/knownhosts/*}. This
1573 case, hosts names are coded in file names
1574 @file{@var{host-name}.@var{algorithm}.pub}. User names are always @code{nil}.
1576 @item @code{tramp-parse-hosts}
1577 @findex tramp-parse-hosts
1579 A function dedicated to @file{/etc/hosts} style files. It returns
1582 @item @code{tramp-parse-passwd}
1583 @findex tramp-parse-passwd
1585 A function which parses @file{/etc/passwd} like files. Obviously, it
1586 can return user names only.
1588 @item @code{tramp-parse-netrc}
1589 @findex tramp-parse-netrc
1591 Finally, a function which parses @file{~/.netrc} like files.
1594 If you want to keep your own data in a file, with your own structure,
1595 you might provide such a function as well. This function must meet
1596 the following conventions:
1598 @defun my-tramp-parse file
1599 @var{file} must be either a file name on your host, or @code{nil}.
1600 The function must return a list of (@var{user} @var{host}), which are
1601 taken as candidates for user and host name completion.
1605 (my-tramp-parse "~/.my-tramp-hosts")
1607 @result{} ((nil "toto") ("daniel" "melancholia"))
1612 @node Password handling
1613 @section Reusing passwords for several connections.
1616 Sometimes it is necessary to connect to the same remote host several
1617 times. Reentering passwords again and again would be annoying, when
1618 the chosen method does not support access without password prompt
1619 through own configuration.
1621 The best recommendation is to use the method's own mechanism for
1622 password handling. Consider @command{ssh-agent} for @option{ssh}-like
1623 methods, or @command{pageant} for @option{plink}-like methods.
1625 However, if you cannot apply such native password handling,
1626 @value{tramp} offers altenatives.
1629 @anchor{Using an authentication file}
1630 @subsection Using an authentication file
1632 @vindex auth-sources
1633 The package @file{auth-source.el}, originally developed in No Gnus,
1634 offers the possibility to read passwords from a file, like FTP does it
1635 from @file{~/.netrc}. The default authentication file is
1636 @file{~/.authinfo.gpg}, this can be changed via the variable
1637 @code{auth-sources}.
1640 A typical entry in the authentication file would be
1643 machine melancholia port scp login daniel password geheim
1646 The port can be any @value{tramp} method (@pxref{Inline methods},
1647 @pxref{External methods}), to match only this method. When you omit
1648 the port, you match all @value{tramp} methods.
1651 A special case are @option{imap}-like methods. Authentication with
1652 the IMAP server is performed via @file{imap.el}, there is no special
1653 need from @value{tramp} point of view. An additional passphrase, used
1654 for symmetric encryption and decryption of the stored messages, should
1655 be given with the special port indication @option{tramp-imap}:
1658 machine melancholia port tramp-imap login daniel password ultrageheim
1662 @anchor{Caching passwords}
1663 @subsection Caching passwords
1665 If there is no authentication file, @value{tramp} caches the passwords
1666 entered by you. They will be reused next time if a connection needs
1667 them for the same user name and host name, independently of the
1670 @vindex password-cache-expiry
1671 Passwords are not saved permanently, that means the password caching
1672 is limited to the lifetime of your @value{emacsname} session. You
1673 can influence the lifetime of password caching by customizing the
1674 variable @code{password-cache-expiry}. The value is the number of
1675 seconds how long passwords are cached. Setting it to @code{nil}
1676 disables the expiration.
1678 @vindex password-cache
1679 If you don't like this feature for security reasons, password caching
1680 can be disabled totally by customizing the variable
1681 @code{password-cache} (setting it to @code{nil}).
1683 Implementation Note: password caching is based on the package
1684 @file{password-cache.el}. For the time being, it is activated only
1685 when this package is seen in the @code{load-path} while loading
1687 @ifset installchapter
1688 If you don't use No Gnus, you can take @file{password.el} from the
1689 @value{tramp} @file{contrib} directory, see @ref{Installation
1694 @node Connection caching
1695 @section Reusing connection related information.
1698 @vindex tramp-persistency-file-name
1699 In order to reduce initial connection time, @value{tramp} stores
1700 connection related information persistently. The variable
1701 @code{tramp-persistency-file-name} keeps the file name where these
1702 information are written. Its default value is
1704 @file{~/.emacs.d/tramp}.
1707 @file{~/.xemacs/tramp}.
1709 It is recommended to choose a local file name.
1711 @value{tramp} reads this file during startup, and writes it when
1712 exiting @value{emacsname}. You can simply remove this file if
1713 @value{tramp} shall be urged to recompute these information next
1714 @value{emacsname} startup time.
1716 Using such persistent information can be disabled by setting
1717 @code{tramp-persistency-file-name} to @code{nil}.
1719 Once consequence of reusing connection related information is that
1720 @var{tramp} needs to distinguish hosts. If you, for example, run a
1721 local @code{sshd} on port 3001, which tunnels @command{ssh} to another
1722 host, you could access both @file{@trampfn{ssh, , localhost,}} and
1723 @file{@trampfn{ssh, , localhost#3001,}}. @var{tramp} would use the
1724 same host related information (like paths, Perl variants, etc) for
1725 both connections, although the information is valid only for one of
1728 In order to avoid trouble, you must use another host name for one of
1729 the connections, like introducing a @option{Host} section in
1730 @file{~/.ssh/config} (@pxref{Frequently Asked Questions}) or applying
1731 multiple hops (@pxref{Multi-hops}).
1733 When @value{tramp} detects a changed operating system version on a
1734 remote host (via the command @command{uname -sr}), it flushes all
1735 connection related information for this host, and opens the
1739 @node Remote Programs
1740 @section How @value{tramp} finds and uses programs on the remote machine.
1742 @value{tramp} depends on a number of programs on the remote host in order to
1743 function, including @command{ls}, @command{test}, @command{find} and
1746 In addition to these required tools, there are various tools that may be
1747 required based on the connection method. See @ref{Inline methods} and
1748 @ref{External methods} for details on these.
1750 Certain other tools, such as @command{perl} (or @command{perl5}) and
1751 @command{grep} will be used if they can be found. When they are
1752 available, they are used to improve the performance and accuracy of
1755 @vindex tramp-remote-path
1756 @vindex tramp-default-remote-path
1757 @vindex tramp-own-remote-path
1758 @defopt tramp-remote-path
1759 When @value{tramp} connects to the remote machine, it searches for the
1760 programs that it can use. The variable @code{tramp-remote-path}
1761 controls the directories searched on the remote machine.
1763 By default, this is set to a reasonable set of defaults for most
1764 machines. The symbol @code{tramp-default-remote-path} is a place
1765 holder, it is replaced by the list of directories received via the
1766 command @command{getconf PATH} on your remote machine. For example,
1767 on GNU Debian this is @file{/bin:/usr/bin}, whereas on Solaris this is
1768 @file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin}. It is
1769 recommended to apply this symbol on top of @code{tramp-remote-path}.
1771 It is possible, however, that your local (or remote ;) system
1772 administrator has put the tools you want in some obscure local
1775 In this case, you can still use them with @value{tramp}. You simply
1776 need to add code to your @file{.emacs} to add the directory to the
1777 remote path. This will then be searched by @value{tramp} when you
1778 connect and the software found.
1780 To add a directory to the remote search path, you could use code such
1784 @i{;; We load @value{tramp} to define the variable.}
1786 @i{;; We have @command{perl} in "/usr/local/perl/bin"}
1787 (add-to-list 'tramp-remote-path "/usr/local/perl/bin")
1790 Another possibility is to reuse the path settings of your remote
1791 account, when you log in. Usually, these settings are overwritten,
1792 because they might not be useful for @value{tramp}. The place holder
1793 @code{tramp-own-remote-path} preserves these settings. You can
1797 (add-to-list 'tramp-remote-path 'tramp-own-remote-path)
1801 @value{tramp} caches several information, like the Perl binary
1802 location. The changed remote search path wouldn't affect these
1803 settings. In order to force @value{tramp} to recompute these values,
1804 you must exit @value{emacsname}, remove your persistency file
1805 (@pxref{Connection caching}), and restart @value{emacsname}.
1808 @node Remote shell setup
1809 @section Remote shell setup hints
1810 @cindex remote shell setup
1811 @cindex @file{.profile} file
1812 @cindex @file{.login} file
1813 @cindex shell init files
1815 As explained in the @ref{Overview} section, @value{tramp} connects to the
1816 remote host and talks to the shell it finds there. Of course, when you
1817 log in, the shell executes its init files. Suppose your init file
1818 requires you to enter the birth date of your mother; clearly @value{tramp}
1819 does not know this and hence fails to log you in to that host.
1821 There are different possible strategies for pursuing this problem. One
1822 strategy is to enable @value{tramp} to deal with all possible situations.
1823 This is a losing battle, since it is not possible to deal with
1824 @emph{all} situations. The other strategy is to require you to set up
1825 the remote host such that it behaves like @value{tramp} expects. This might
1826 be inconvenient because you have to invest a lot of effort into shell
1827 setup before you can begin to use @value{tramp}.
1829 The package, therefore, pursues a combined approach. It tries to
1830 figure out some of the more common setups, and only requires you to
1831 avoid really exotic stuff. For example, it looks through a list of
1832 directories to find some programs on the remote host. And also, it
1833 knows that it is not obvious how to check whether a file exists, and
1834 therefore it tries different possibilities. (On some hosts and
1835 shells, the command @command{test -e} does the trick, on some hosts
1836 the shell builtin doesn't work but the program @command{/usr/bin/test
1837 -e} or @command{/bin/test -e} works. And on still other hosts,
1838 @command{ls -d} is the right way to do this.)
1840 Below you find a discussion of a few things that @value{tramp} does not deal
1841 with, and that you therefore have to set up correctly.
1844 @item @var{shell-prompt-pattern}
1845 @vindex shell-prompt-pattern
1847 After logging in to the remote host, @value{tramp} has to wait for the remote
1848 shell startup to finish before it can send commands to the remote
1849 shell. The strategy here is to wait for the shell prompt. In order to
1850 recognize the shell prompt, the variable @code{shell-prompt-pattern} has
1851 to be set correctly to recognize the shell prompt on the remote host.
1853 Note that @value{tramp} requires the match for @code{shell-prompt-pattern}
1854 to be at the end of the buffer. Many people have something like the
1855 following as the value for the variable: @code{"^[^>$][>$] *"}. Now
1856 suppose your shell prompt is @code{a <b> c $ }. In this case,
1857 @value{tramp} recognizes the @code{>} character as the end of the prompt,
1858 but it is not at the end of the buffer.
1860 @item @var{tramp-shell-prompt-pattern}
1861 @vindex tramp-shell-prompt-pattern
1863 This regular expression is used by @value{tramp} in the same way as
1864 @code{shell-prompt-pattern}, to match prompts from the remote shell.
1865 This second variable exists because the prompt from the remote shell
1866 might be different from the prompt from a local shell --- after all,
1867 the whole point of @value{tramp} is to log in to remote hosts as a
1868 different user. The default value of
1869 @code{tramp-shell-prompt-pattern} is the same as the default value of
1870 @code{shell-prompt-pattern}, which is reported to work well in many
1873 @item @var{tramp-password-prompt-regexp}
1874 @vindex tramp-password-prompt-regexp
1875 @vindex tramp-wrong-passwd-regexp
1877 During login, @value{tramp} might be forced to enter a password or a
1878 passphrase. The difference between both is that a password is
1879 requested from the shell on the remote host, while a passphrase is
1880 needed for accessing local authentication information, like your ssh
1883 @var{tramp-password-prompt-regexp} handles the detection of such
1884 requests for English environments. When you use another localization
1885 of your (local or remote) host, you might need to adapt this. Example:
1889 tramp-password-prompt-regexp
1893 '("passphrase" "Passphrase"
1895 "password" "Password"
1897 "passwort" "Passwort"
1899 "mot de passe" "Mot de passe") t)