1 \input texinfo @c -*-texinfo-*-
2 @setfilename ../../info/tramp
4 @settitle TRAMP User Manual
7 @c This is *so* much nicer :)
10 @c In the Tramp CVS, the version number is auto-frobbed from
11 @c configure.ac, so you should edit that file and run
12 @c "autoconf && ./configure" to change the version number.
14 @c Additionally, flags are set with respect to the Emacs flavor; and
15 @c depending whether Tramp is packaged into (X)Emacs, or standalone.
17 @include trampver.texi
19 @c Macro for formatting a filename according to the respective syntax.
20 @c xxx and yyy are auxiliary macros in order to omit leading and
21 @c trailing whitespace. Not very elegant, but I don't know it better.
27 @macro yyy {one, two}@c
35 @macro trampfn {method, user, host, localname}@c
36 @value{prefix}@yyy{\method\,@value{postfixhop}}@yyy{\user\,@@}\host\@value{postfix}\localname\@c
40 Copyright @copyright{} 1999-2011 Free Software Foundation, Inc.
43 Permission is granted to copy, distribute and/or modify this document
44 under the terms of the GNU Free Documentation License, Version 1.3 or
45 any later version published by the Free Software Foundation; with no
46 Invariant Sections, with the Front-Cover texts being ``A GNU Manual'',
47 and with the Back-Cover Texts as in (a) below. A copy of the license
48 is included in the section entitled ``GNU Free Documentation License''.
50 (a) The FSF's Back-Cover Text is: ``You have the freedom to
51 copy and modify this GNU manual. Buying copies from the FSF
52 supports it in developing GNU and promoting software freedom.''
56 @c Entries for @command{install-info} to use
57 @dircategory @value{emacsname} network features
59 * TRAMP: (tramp). Transparent Remote Access, Multiple Protocol
60 @value{emacsname} remote file access via rsh and rcp.
64 @title @value{tramp} version @value{trampver} User Manual
65 @author by Daniel Pittman
66 @author based on documentation by Kai Gro@ss{}johann
74 @node Top, Overview, (dir), (dir)
75 @top @value{tramp} version @value{trampver} User Manual
77 This file documents @value{tramp} version @value{trampver}, a remote file
78 editing package for @value{emacsname}.
80 @value{tramp} stands for `Transparent Remote (file) Access, Multiple
81 Protocol'. This package provides remote file editing, similar to
82 @value{ftppackagename}.
84 The difference is that @value{ftppackagename} uses FTP to transfer
85 files between the local and the remote host, whereas @value{tramp} uses a
86 combination of @command{rsh} and @command{rcp} or other work-alike
87 programs, such as @command{ssh}/@command{scp}.
89 You can find the latest version of this document on the web at
90 @uref{http://www.gnu.org/software/tramp/}.
92 @c Pointer to the other Emacs flavor is necessary only in case of
93 @c standalone installation.
95 The manual has been generated for @value{emacsname}.
97 If you want to read the info pages for @value{emacsothername}, you
98 should read in @ref{Installation} how to create them.
101 If you're using the other Emacs flavor, you should read the
102 @uref{@value{emacsotherfilename}, @value{emacsothername}} pages.
107 The latest release of @value{tramp} is available for
108 @uref{ftp://ftp.gnu.org/gnu/tramp/, download}, or you may see
109 @ref{Obtaining Tramp} for more details, including the CVS server
112 @value{tramp} also has a @uref{http://savannah.gnu.org/projects/tramp/,
113 Savannah Project Page}.
116 There is a mailing list for @value{tramp}, available at
117 @email{tramp-devel@@gnu.org}, and archived at
118 @uref{http://lists.gnu.org/archive/html/tramp-devel/, the
119 @value{tramp} Mail Archive}.
121 Older archives are located at
122 @uref{http://sourceforge.net/mailarchive/forum.php?forum=tramp-devel,
123 SourceForge Mail Archive} and
124 @uref{http://www.mail-archive.com/emacs-rcp@@ls6.cs.uni-dortmund.de/,
126 @c in HTML output, there's no new paragraph.
135 * Overview:: What @value{tramp} can and cannot do.
139 * Obtaining Tramp:: How to obtain @value{tramp}.
140 * History:: History of @value{tramp}.
141 @ifset installchapter
142 * Installation:: Installing @value{tramp} with your @value{emacsname}.
144 * Configuration:: Configuring @value{tramp} for use.
145 * Usage:: An overview of the operation of @value{tramp}.
146 * Bug Reports:: Reporting Bugs and Problems.
147 * Frequently Asked Questions:: Questions and answers from the mailing list.
148 * Function Index:: @value{tramp} functions.
149 * Variable Index:: User options and variables.
150 * Concept Index:: An item for each concept.
154 * Files directories and localnames:: How file names, directories and localnames are mangled and managed.
155 * Traces and Profiles:: How to Customize Traces.
156 * Issues:: Debatable Issues and What Was Decided.
158 * GNU Free Documentation License:: The license for this documentation.
161 --- The Detailed Node Listing ---
163 @ifset installchapter
164 Installing @value{tramp} with your @value{emacsname}
166 * Installation parameters:: Parameters in order to control installation.
167 * Load paths:: How to plug-in @value{tramp} into your environment.
171 Configuring @value{tramp} for use
173 * Connection types:: Types of connections made to remote machines.
174 * Inline methods:: Inline methods.
175 * External methods:: External methods.
177 * GVFS based methods:: GVFS based external methods.
180 * Gateway methods:: Gateway methods.
182 * Default Method:: Selecting a default method.
183 * Default User:: Selecting a default user.
184 * Default Host:: Selecting a default host.
185 * Multi-hops:: Connecting to a remote host using multiple hops.
186 * Customizing Methods:: Using Non-Standard Methods.
187 * Customizing Completion:: Selecting config files for user/host name completion.
188 * Password handling:: Reusing passwords for several connections.
189 * Connection caching:: Reusing connection related information.
190 * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine.
191 * Remote shell setup:: Remote shell setup hints.
192 * Windows setup hints:: Issues with Cygwin ssh.
193 * Auto-save and Backup:: Auto-save and Backup.
197 * Filename Syntax:: @value{tramp} filename conventions.
198 * Alternative Syntax:: URL-like filename syntax.
199 * Filename completion:: Filename completion.
200 * Remote processes:: Integration with other @value{emacsname} packages.
201 * Cleanup remote connections:: Cleanup remote connections.
203 How file names, directories and localnames are mangled and managed
205 * Localname deconstruction:: Breaking a localname into its components.
207 * External packages:: Integration with external Lisp packages.
214 @chapter An overview of @value{tramp}
217 After the installation of @value{tramp} into your @value{emacsname}, you
218 will be able to access files on remote machines as though they were
219 local. Access to the remote file system for editing files, version
220 control, and @code{dired} are transparently enabled.
222 Your access to the remote machine can be with the @command{rsh},
223 @command{rlogin}, @command{telnet} programs or with any similar
224 connection method. This connection must pass @acronym{ASCII}
225 successfully to be usable but need not be 8-bit clean.
227 The package provides support for @command{ssh} connections out of the
228 box, one of the more common uses of the package. This allows
229 relatively secure access to machines, especially if @command{ftp}
232 Under Windows, @value{tramp} is integrated with the PuTTY package,
233 using the @command{plink} program.
235 The majority of activity carried out by @value{tramp} requires only that
236 the remote login is possible and is carried out at the terminal. In
237 order to access remote files @value{tramp} needs to transfer their content
238 to the local machine temporarily.
240 @value{tramp} can transfer files between the machines in a variety of ways.
241 The details are easy to select, depending on your needs and the
242 machines in question.
244 The fastest transfer methods for large files rely on a remote file
245 transfer package such as @command{rcp}, @command{scp}, @command{rsync}
246 or (under Windows) @command{pscp}.
248 If the remote copy methods are not suitable for you, @value{tramp} also
249 supports the use of encoded transfers directly through the shell.
250 This requires that the @command{mimencode} or @command{uuencode} tools
251 are available on the remote machine. These methods are generally
252 faster for small files.
254 @value{tramp} is still under active development and any problems you encounter,
255 trivial or major, should be reported to the @value{tramp} developers.
259 @subsubheading Behind the scenes
260 @cindex behind the scenes
261 @cindex details of operation
264 This section tries to explain what goes on behind the scenes when you
265 access a remote file through @value{tramp}.
267 Suppose you type @kbd{C-x C-f} and enter part of an @value{tramp} file name,
268 then hit @kbd{@key{TAB}} for completion. Suppose further that this is
269 the first time that @value{tramp} is invoked for the host in question. Here's
274 @value{tramp} discovers that it needs a connection to the host. So it
275 invokes @samp{telnet @var{host}} or @samp{rsh @var{host} -l
276 @var{user}} or a similar tool to connect to the remote host.
277 Communication with this process happens through an
278 @value{emacsname} buffer, that is, the output from the remote end
282 The remote host may prompt for a login name (for @command{telnet}).
283 The login name is given in the file name, so @value{tramp} sends the
284 login name and a newline.
287 The remote host may prompt for a password or pass phrase (for
288 @command{rsh} or for @command{telnet} after sending the login name).
289 @value{tramp} displays the prompt in the minibuffer, asking you for the
290 password or pass phrase.
292 You enter the password or pass phrase. @value{tramp} sends it to the remote
293 host, followed by a newline.
296 @value{tramp} now waits for the shell prompt or for a message that the login
299 If @value{tramp} sees neither of them after a certain period of time
300 (a minute, say), then it issues an error message saying that it
301 couldn't find the remote shell prompt and shows you what the remote
304 If @value{tramp} sees a @samp{login failed} message, it tells you so,
305 aborts the login attempt and allows you to try again.
308 Suppose that the login was successful and @value{tramp} sees the shell prompt
309 from the remote host. Now @value{tramp} invokes @command{/bin/sh} because
310 Bourne shells and C shells have different command
311 syntaxes.@footnote{Invoking @command{/bin/sh} will fail if your login
312 shell doesn't recognize @samp{exec /bin/sh} as a valid command.
313 Maybe you use the Scheme shell @command{scsh}@dots{}}
315 After the Bourne shell has come up, @value{tramp} sends a few commands to
316 ensure a good working environment. It turns off echoing, it sets the
317 shell prompt, and a few other things.
320 Now the remote shell is up and it good working order. Remember, what
321 was supposed to happen is that @value{tramp} tries to find out what files exist
322 on the remote host so that it can do filename completion.
324 So, @value{tramp} basically issues @command{cd} and @command{ls} commands and
325 also sometimes @command{echo} with globbing. Another command that is
326 often used is @command{test} to find out whether a file is writable or a
327 directory or the like. The output of each command is parsed for the
331 Suppose you are finished with filename completion, have entered @kbd{C-x
332 C-f}, a full file name and hit @kbd{@key{RET}}. Now comes the time to
333 transfer the file contents from the remote host to the local host so
334 that you can edit them.
336 See above for an explanation of how @value{tramp} transfers the file contents.
338 For inline transfers, @value{tramp} issues a command like @samp{mimencode -b
339 /path/to/remote/file}, waits until the output has accumulated in the
340 buffer that's used for communication, then decodes that output to
341 produce the file contents.
343 For external transfers, @value{tramp} issues a command like the
346 rcp user@@host:/path/to/remote/file /tmp/tramp.4711
348 It then reads the local temporary file @file{/tmp/tramp.4711} into a
349 buffer and deletes the temporary file.
352 You now edit the buffer contents, blithely unaware of what has happened
353 behind the scenes. (Unless you have read this section, that is.) When
354 you are finished, you type @kbd{C-x C-s} to save the buffer.
357 Again, @value{tramp} transfers the file contents to the remote host
358 either inline or external. This is the reverse of what happens when
362 I hope this has provided you with a basic overview of what happens
363 behind the scenes when you open a file with @value{tramp}.
367 @node Obtaining Tramp
368 @chapter Obtaining Tramp.
369 @cindex obtaining Tramp
371 @value{tramp} is freely available on the Internet and the latest
372 release may be downloaded from @uref{ftp://ftp.gnu.org/gnu/tramp/}.
373 This release includes the full documentation and code for
374 @value{tramp}, suitable for installation. But Emacs (22 or later)
375 includes @value{tramp} already, and there is a @value{tramp} package
376 for XEmacs, as well. So maybe it is easier to just use those. But if
377 you want the bleeding edge, read on@dots{...}
379 For the especially brave, @value{tramp} is available from CVS. The CVS
380 version is the latest version of the code and may contain incomplete
381 features or new issues. Use these versions at your own risk.
383 Instructions for obtaining the latest development version of @value{tramp}
384 from CVS can be found by going to the Savannah project page at the
385 following URL and then clicking on the CVS link in the navigation bar
389 @uref{http://savannah.gnu.org/projects/tramp/}
392 Or follow the example session below:
395 ] @strong{cd ~/@value{emacsdir}}
396 ] @strong{export CVS_RSH="ssh"}
397 ] @strong{cvs -z3 -d:pserver:anonymous@@cvs.savannah.gnu.org:/sources/tramp co tramp}
401 You should now have a directory @file{~/@value{emacsdir}/tramp}
402 containing the latest version of @value{tramp}. You can fetch the latest
403 updates from the repository by issuing the command:
406 ] @strong{cd ~/@value{emacsdir}/tramp}
407 ] @strong{export CVS_RSH="ssh"}
408 ] @strong{cvs update -d}
412 Once you've got updated files from the CVS repository, you need to run
413 @command{autoconf} in order to get an up-to-date @file{configure}
417 ] @strong{cd ~/@value{emacsdir}/tramp}
423 @chapter History of @value{tramp}
425 @cindex development history
427 Development was started end of November 1998. The package was called
428 @file{rssh.el}, back then. It only provided one method to access a
429 file, using @command{ssh} to log in to a remote host and using
430 @command{scp} to transfer the file contents. After a while, the name
431 was changed to @file{rcp.el}, and now it's @value{tramp}. Along the way,
432 many more methods for getting a remote shell and for transferring the
433 file contents were added. Support for VC was added.
435 After that, there were added the multi-hop methods in April 2000 and
436 the unification of @value{tramp} and Ange-FTP filenames in July 2002.
437 In July 2004, multi-hop methods have been replaced by proxy hosts.
438 Running commands on remote hosts was introduced in December 2005.
440 Support of gateways exists since April 2007.
443 GVFS integration started in February 2009.
446 In December 2001, @value{tramp} has been added to the XEmacs package
447 repository. Being part of the Emacs repository happened in June 2002,
448 the first release including @value{tramp} was Emacs 22.1.
450 @value{tramp} is also a Debian GNU/Linux package since February 2001.
453 @c Installation chapter is necessary only in case of standalone
454 @c installation. Text taken from trampinst.texi.
455 @ifset installchapter
456 @include trampinst.texi
460 @chapter Configuring @value{tramp} for use
461 @cindex configuration
463 @cindex default configuration
464 @value{tramp} is (normally) fully functional when it is initially
465 installed. It is initially configured to use the @command{scp}
466 program to connect to the remote host. So in the easiest case, you
467 just type @kbd{C-x C-f} and then enter the filename
468 @file{@trampfn{, user, machine, /path/to.file}}.
470 On some hosts, there are problems with opening a connection. These are
471 related to the behavior of the remote shell. See @xref{Remote shell
472 setup}, for details on this.
474 If you do not wish to use these commands to connect to the remote
475 host, you should change the default connection and transfer method
476 that @value{tramp} uses. There are several different methods that @value{tramp}
477 can use to connect to remote machines and transfer files
478 (@pxref{Connection types}).
480 If you don't know which method is right for you, see @xref{Default
485 * Connection types:: Types of connections made to remote machines.
486 * Inline methods:: Inline methods.
487 * External methods:: External methods.
489 * GVFS based methods:: GVFS based external methods.
492 * Gateway methods:: Gateway methods.
494 * Default Method:: Selecting a default method.
495 Here we also try to help those who
496 don't have the foggiest which method
498 * Default User:: Selecting a default user.
499 * Default Host:: Selecting a default host.
500 * Multi-hops:: Connecting to a remote host using multiple hops.
501 * Customizing Methods:: Using Non-Standard Methods.
502 * Customizing Completion:: Selecting config files for user/host name completion.
503 * Password handling:: Reusing passwords for several connections.
504 * Connection caching:: Reusing connection related information.
505 * Remote Programs:: How @value{tramp} finds and uses programs on the remote machine.
506 * Remote shell setup:: Remote shell setup hints.
507 * Windows setup hints:: Issues with Cygwin ssh.
508 * Auto-save and Backup:: Auto-save and Backup.
512 @node Connection types
513 @section Types of connections made to remote machines.
514 @cindex connection types, overview
516 There are two basic types of transfer methods, each with its own
517 advantages and limitations. Both types of connection make use of a
518 remote shell access program such as @command{rsh}, @command{ssh} or
519 @command{telnet} to connect to the remote machine.
521 This connection is used to perform many of the operations that @value{tramp}
522 requires to make the remote file system transparently accessible from
523 the local machine. It is only when visiting files that the methods
526 @cindex inline methods
527 @cindex external methods
528 @cindex methods, inline
529 @cindex methods, external
530 Loading or saving a remote file requires that the content of the file
531 be transfered between the two machines. The content of the file can
532 be transfered using one of two methods: the @dfn{inline method} over
533 the same connection used to log in to the remote machine, or the
534 @dfn{external method} through another connection using a remote copy
535 program such as @command{rcp}, @command{scp} or @command{rsync}.
537 The performance of the external methods is generally better than that
538 of the inline methods, at least for large files. This is caused by
539 the need to encode and decode the data when transferring inline.
541 The one exception to this rule are the @command{scp} based transfer
542 methods. While these methods do see better performance when actually
543 transferring files, the overhead of the cryptographic negotiation at
544 startup may drown out the improvement in file transfer times.
546 External methods should be configured such a way that they don't
547 require a password (with @command{ssh-agent}, or such alike). Modern
548 @command{scp} implementations offer options to reuse existing
549 @command{ssh} connections, see method @command{scpc}. If it isn't
550 possible, you should consider @ref{Password handling}, otherwise you
551 will be prompted for a password every copy action.
555 @section Inline methods
556 @cindex inline methods
557 @cindex methods, inline
559 The inline methods in @value{tramp} are quite powerful and can work in
560 situations where you cannot use an external transfer program to connect.
561 Inline methods are the only methods that work when connecting to the
562 remote machine via telnet. (There are also strange inline methods which
563 allow you to transfer files between @emph{user identities} rather than
566 These methods depend on the existence of a suitable encoding and
567 decoding command on remote machine. Locally, @value{tramp} may be able to
568 use features of @value{emacsname} to decode and encode the files or
569 it may require access to external commands to perform that task.
573 @cindex base-64 encoding
574 @value{tramp} checks the availability and usability of commands like
575 @command{mimencode} (part of the @command{metamail} package) or
576 @command{uuencode} on the remote host. The first reliable command
577 will be used. The search path can be customized, see @ref{Remote
580 If both commands aren't available on the remote host, @value{tramp}
581 transfers a small piece of Perl code to the remote host, and tries to
582 apply it for encoding and decoding.
584 The variable @var{tramp-inline-compress-start-size} controls, whether
585 a file shall be compressed before encoding. This could increase
586 transfer speed for large text files.
594 Connect to the remote host with @command{rsh}. Due to the unsecure
595 connection it is recommended for very local host topology only.
597 On operating systems which provide the command @command{remsh} instead
598 of @command{rsh}, you can use the method @option{remsh}. This is true
599 for HP-UX or Cray UNICOS, for example.
606 Connect to the remote host with @command{ssh}. This is identical to
607 the previous option except that the @command{ssh} package is used,
608 making the connection more secure.
610 There are also two variants, @option{ssh1} and @option{ssh2}, that
611 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
612 explicitly select whether you want to use the SSH protocol version 1
613 or 2 to connect to the remote host. (You can also specify in
614 @file{~/.ssh/config}, the SSH configuration file, which protocol
615 should be used, and use the regular @option{ssh} method.)
617 All the methods based on @command{ssh} have an additional feature: you
618 can specify a host name which looks like @file{host#42} (the real host
619 name, then a hash sign, then a port number). This means to connect to
620 the given host but to also pass @code{-p 42} as arguments to the
621 @command{ssh} command.
624 @item @option{telnet}
625 @cindex method telnet
626 @cindex telnet method
628 Connect to the remote host with @command{telnet}. This is as unsecure
629 as the @option{rsh} method.
636 This method does not connect to a remote host at all, rather it uses
637 the @command{su} program to allow you to edit files as another user.
638 That means, the specified host name in the file name must be either
639 @samp{localhost} or the host name as returned by the function
640 @command{(system-name)}. For an exception of this rule see
648 This is similar to the @option{su} method, but it uses @command{sudo}
649 rather than @command{su} to become a different user.
651 Note that @command{sudo} must be configured to allow you to start a
652 shell as the user. It would be nice if it was sufficient if
653 @command{ls} and @command{mimencode} were allowed, but that is not
654 easy to implement, so I haven't got around to it, yet.
661 As you would expect, this is similar to @option{ssh}, only a little
662 different. Whereas @option{ssh} opens a normal interactive shell on
663 the remote host, this option uses @samp{ssh -t -t @var{host} -l
664 @var{user} /bin/sh} to open a connection. This is useful for users
665 where the normal login shell is set up to ask them a number of
666 questions when logging in. This procedure avoids these questions, and
667 just gives @value{tramp} a more-or-less `standard' login shell to work
670 Note that this procedure does not eliminate questions asked by
671 @command{ssh} itself. For example, @command{ssh} might ask ``Are you
672 sure you want to continue connecting?'' if the host key of the remote
673 host is not known. @value{tramp} does not know how to deal with such a
674 question (yet), therefore you will need to make sure that you can log
675 in without such questions.
677 This is also useful for Windows users where @command{ssh}, when
678 invoked from an @value{emacsname} buffer, tells them that it is not
679 allocating a pseudo tty. When this happens, the login shell is wont
680 to not print any shell prompt, which confuses @value{tramp} mightily.
682 This supports the @samp{-p} argument.
685 @item @option{krlogin}
686 @cindex method krlogin
687 @cindex krlogin method
688 @cindex Kerberos (with krlogin method)
690 This method is also similar to @option{ssh}. It only uses the
691 @command{krlogin -x} command to log in to the remote host.
697 @cindex Kerberos (with ksu method)
699 This is another method from the Kerberos suite. It behaves like @option{su}.
706 This method is mostly interesting for Windows users using the PuTTY
707 implementation of SSH. It uses @samp{plink -ssh} to log in to the
710 This supports the @samp{-P} argument.
712 Additionally, the methods @option{plink1} and @option{plink2} are
713 provided, which call @samp{plink -1 -ssh} or @samp{plink -2 -ssh} in
714 order to use SSH protocol version 1 or 2 explicitly.
716 CCC: Do we have to connect to the remote host once from the command
717 line to accept the SSH key? Maybe this can be made automatic?
719 CCC: Say something about the first shell command failing. This might
720 be due to a wrong setting of @code{tramp-rsh-end-of-line}.
723 @item @option{plinkx}
724 @cindex method plinkx
725 @cindex plinkx method
727 Another method using PuTTY on Windows. Instead of host names, it
728 expects PuTTY session names, calling @samp{plink -load @var{session}
729 -t"}. User names are relevant only in case the corresponding session
730 hasn't defined a user name. Different port numbers must be defined in
736 @node External methods
737 @section External methods
738 @cindex methods, external
739 @cindex external methods
741 The external methods operate through multiple channels, using the
742 remote shell connection for many actions while delegating file
743 transfers to an external transfer utility.
745 This saves the overhead of encoding and decoding that multiplexing the
746 transfer through the one connection has with the inline methods.
748 Since external methods need their own overhead opening a new channel,
749 all files which are smaller than @var{tramp-copy-size-limit} are still
750 transferred with the corresponding inline method. It should provide a
751 fair trade-off between both approaches.
754 @item @option{rcp} --- @command{rsh} and @command{rcp}
757 @cindex rcp (with rcp method)
758 @cindex rsh (with rcp method)
760 This method uses the @command{rsh} and @command{rcp} commands to connect
761 to the remote machine and transfer files. This is probably the fastest
762 connection method available.
764 The alternative method @option{remcp} uses the @command{remsh} and
765 @command{rcp} commands. It should be applied on machines where
766 @command{remsh} is used instead of @command{rsh}.
769 @item @option{scp} --- @command{ssh} and @command{scp}
772 @cindex scp (with scp method)
773 @cindex ssh (with scp method)
775 Using @command{ssh} to connect to the remote host and @command{scp} to
776 transfer files between the machines is the best method for securely
777 connecting to a remote machine and accessing files.
779 The performance of this option is also quite good. It may be slower than
780 the inline methods when you often open and close small files however.
781 The cost of the cryptographic handshake at the start of an @command{scp}
782 session can begin to absorb the advantage that the lack of encoding and
785 There are also two variants, @option{scp1} and @option{scp2}, that
786 call @samp{ssh -1} and @samp{ssh -2}, respectively. This way, you can
787 explicitly select whether you want to use the SSH protocol version 1
788 or 2 to connect to the remote host. (You can also specify in
789 @file{~/.ssh/config}, the SSH configuration file, which protocol
790 should be used, and use the regular @option{scp} method.)
792 All the @command{ssh} based methods support the @samp{-p} feature
793 where you can specify a port number to connect to in the host name.
794 For example, the host name @file{host#42} tells @value{tramp} to
795 specify @samp{-p 42} in the argument list for @command{ssh}, and to
796 specify @samp{-P 42} in the argument list for @command{scp}.
799 @item @option{sftp} --- @command{ssh} and @command{sftp}
802 @cindex sftp (with sftp method)
803 @cindex ssh (with sftp method)
805 That is mostly the same method as @option{scp}, but using
806 @command{sftp} as transfer command. So the same remarks are valid.
808 This command does not work like @value{ftppackagename}, where
809 @command{ftp} is called interactively, and all commands are send from
810 within this session. Instead of, @command{ssh} is used for login.
812 This method supports the @samp{-p} argument.
815 @item @option{rsync} --- @command{ssh} and @command{rsync}
818 @cindex rsync (with rsync method)
819 @cindex ssh (with rsync method)
821 Using the @command{ssh} command to connect securely to the remote
822 machine and the @command{rsync} command to transfer files is almost
823 identical to the @option{scp} method.
825 While @command{rsync} performs much better than @command{scp} when
826 transferring files that exist on both hosts, this advantage is lost if
827 the file exists only on one side of the connection. A file can exists
828 on both the remote and local host, when you copy a file from/to a
829 remote host. When you just open a file from the remote host (or write
830 a file there), a temporary file on the local side is kept as long as
831 the corresponding buffer, visiting this file, is alive.
833 This method supports the @samp{-p} argument.
836 @item @option{scpx} --- @command{ssh} and @command{scp}
839 @cindex scp (with scpx method)
840 @cindex ssh (with scpx method)
842 As you would expect, this is similar to @option{scp}, only a little
843 different. Whereas @option{scp} opens a normal interactive shell on
844 the remote host, this option uses @samp{ssh -t -t @var{host} -l
845 @var{user} /bin/sh} to open a connection. This is useful for users
846 where the normal login shell is set up to ask them a number of
847 questions when logging in. This procedure avoids these questions, and
848 just gives @value{tramp} a more-or-less `standard' login shell to work
851 This is also useful for Windows users where @command{ssh}, when
852 invoked from an @value{emacsname} buffer, tells them that it is not
853 allocating a pseudo tty. When this happens, the login shell is wont
854 to not print any shell prompt, which confuses @value{tramp} mightily.
856 This method supports the @samp{-p} argument.
859 @item @option{scpc} --- @command{ssh} and @command{scp}
862 @cindex scp (with scpc method)
863 @cindex ssh (with scpc method)
865 Newer versions of @option{ssh} (for example OpenSSH 4) offer an option
866 @option{ControlMaster}. This allows @option{scp} to reuse an existing
867 @option{ssh} channel, which increases performance.
869 Before you use this method, you shall check whether your @option{ssh}
870 implementation does support this option. Try from the command line
873 ssh localhost -o ControlMaster=yes
876 This method supports the @samp{-p} argument.
879 @item @option{rsyncc} --- @command{ssh} and @command{rsync}
880 @cindex method rsyncc
881 @cindex rsyncc method
882 @cindex rsync (with rsyncc method)
883 @cindex ssh (with rsyncc method)
885 Like the @option{scpc} method, @option{rsyncc} improves the underlying
886 @command{ssh} connection by the option @option{ControlMaster}. This
887 allows @command{rsync} to reuse an existing @command{ssh} channel,
888 which increases performance.
890 This method supports the @samp{-p} argument.
893 @item @option{pscp} --- @command{plink} and @command{pscp}
896 @cindex pscp (with pscp method)
897 @cindex plink (with pscp method)
898 @cindex PuTTY (with pscp method)
900 This method is similar to @option{scp}, but it uses the
901 @command{plink} command to connect to the remote host, and it uses
902 @command{pscp} for transferring the files. These programs are part
903 of PuTTY, an SSH implementation for Windows.
905 This method supports the @samp{-P} argument.
908 @item @option{psftp} --- @command{plink} and @command{psftp}
911 @cindex psftp (with psftp method)
912 @cindex plink (with psftp method)
913 @cindex PuTTY (with psftp method)
915 As you would expect, this method is similar to @option{sftp}, but it
916 uses the @command{plink} command to connect to the remote host, and it
917 uses @command{psftp} for transferring the files. These programs are
918 part of PuTTY, an SSH implementation for Windows.
920 This method supports the @samp{-P} argument.
923 @item @option{fcp} --- @command{fsh} and @command{fcp}
926 @cindex fsh (with fcp method)
927 @cindex fcp (with fcp method)
929 This method is similar to @option{scp}, but it uses the @command{fsh}
930 command to connect to the remote host, and it uses @command{fcp} for
931 transferring the files. @command{fsh/fcp} are a front-end for
932 @command{ssh} which allow for reusing the same @command{ssh} session
933 for submitting several commands. This avoids the startup overhead of
934 @command{scp} (which has to establish a secure connection whenever it
935 is called). Note, however, that you can also use one of the inline
936 methods to achieve a similar effect.
938 This method uses the command @samp{fsh @var{host} -l @var{user}
939 /bin/sh -i} to establish the connection, it does not work to just say
940 @command{fsh @var{host} -l @var{user}}.
945 There is no inline method using @command{fsh} as the multiplexing
946 provided by the program is not very useful in our context. @value{tramp}
947 opens just one connection to the remote host and then keeps it open,
955 This is not a native @value{tramp} method. Instead, it forwards all
956 requests to @value{ftppackagename}.
958 This works only for unified filenames, see @ref{Issues}.
962 @item @option{smb} --- @command{smbclient}
966 This is another not natural @value{tramp} method. It uses the
967 @command{smbclient} command on different Unices in order to connect to
968 an SMB server. An SMB server might be a Samba (or CIFS) server on
969 another UNIX host or, more interesting, a host running MS Windows. So
970 far, it is tested against MS Windows NT, MS Windows 2000, and MS
973 The first directory in the localname must be a share name on the remote
974 host. Remember that the @code{$} character, in which default shares
975 usually end, must be written @code{$$} due to environment variable
976 substitution in file names. If no share name is given (i.e. remote
977 directory @code{/}), all available shares are listed.
979 Since authorization is done on share level, you will always be
980 prompted for a password if you access another share on the same host.
981 This can be suppressed by @ref{Password handling}.
983 For authorization, MS Windows uses both a user name and a domain name.
984 Because of this, the @value{tramp} syntax has been extended: you can
985 specify a user name which looks like @code{user%domain} (the real user
986 name, then a percent sign, then the domain name). So, to connect to
987 the machine @code{melancholia} as user @code{daniel} of the domain
988 @code{BIZARRE}, and edit @file{.emacs} in the home directory (share
989 @code{daniel$}) I would specify the filename @file{@trampfn{smb,
990 daniel%BIZARRE, melancholia, /daniel$$/.emacs}}.
992 Depending on the Windows domain configuration, a Windows user might be
993 considered as domain user per default. In order to connect as local
994 user, the WINS name of that machine must be given as domain name.
995 Usually, it is the machine name in capital letters. In the example
996 above, the local user @code{daniel} would be specified as
997 @file{@trampfn{smb, daniel%MELANCHOLIA, melancholia, /daniel$$/.emacs}}.
999 The domain name as well as the user name are optional. If no user
1000 name is specified at all, the anonymous user (without password
1001 prompting) is assumed. This is different from all other @value{tramp}
1002 methods, where in such a case the local user name is taken.
1004 The @option{smb} method supports the @samp{-p} argument.
1006 @strong{Please note:} If @value{emacsname} runs locally under MS
1007 Windows, this method isn't available. Instead, you can use UNC
1008 file names like @file{//melancholia/daniel$$/.emacs}. The only
1009 disadvantage is that there's no possibility to specify another user
1015 @node GVFS based methods
1016 @section GVFS based external methods
1017 @cindex methods, gvfs
1018 @cindex gvfs based methods
1021 The connection methods described in this section are based on GVFS
1022 @uref{http://en.wikipedia.org/wiki/GVFS}. Via GVFS, the remote
1023 filesystem is mounted locally through FUSE. @value{tramp} uses
1024 this local mounted directory internally.
1026 The communication with GVFS is implemented via D-Bus messages.
1027 Therefore, your @value{emacsname} must have D-Bus integration,
1028 @pxref{Top, , D-Bus, dbus}.
1037 This method provides access to WebDAV files and directories. There
1038 exists also the external method @option{davs}, which uses SSL
1039 encryption for the access.
1041 Both methods support the port number specification as discussed above.
1048 OBEX is an FTP-like access protocol for simple devices, like cell
1049 phones. For the time being, @value{tramp} only supports OBEX over Bluetooth.
1052 @item @option{synce}
1053 @cindex method synce
1054 @cindex synce method
1056 The @option{synce} method allows communication with Windows Mobile
1057 devices. Beside GVFS for mounting remote files and directories via
1058 FUSE, it also needs the SYNCE-GVFS plugin.
1061 @defopt tramp-gvfs-methods
1062 This customer option, a list, defines the external methods which
1063 shall be used with GVFS. Per default, these are @option{dav},
1064 @option{davs}, @option{obex} and @option{synce}. Other possible
1065 values are @option{ftp}, @option{sftp} and @option{smb}.
1071 @node Gateway methods
1072 @section Gateway methods
1073 @cindex methods, gateway
1074 @cindex gateway methods
1076 Gateway methods are not methods to access a remote host directly.
1077 These methods are intended to pass firewalls or proxy servers.
1078 Therefore, they can be used for proxy host declarations
1079 (@pxref{Multi-hops}) only.
1081 A gateway method must always come along with a method which supports
1082 port setting. This is because @value{tramp} targets the accompanied
1083 method to @file{localhost#random_port}, from where the firewall or
1084 proxy server is accessed.
1086 Gateway methods support user name and password declarations. These
1087 are used to authenticate towards the corresponding firewall or proxy
1088 server. They can be passed only if your friendly administrator has
1089 granted your access.
1092 @item @option{tunnel}
1093 @cindex method tunnel
1094 @cindex tunnel method
1096 This method implements an HTTP tunnel via the @command{CONNECT}
1097 command (see RFC 2616, 2817). Any HTTP 1.1 compliant (proxy) server
1098 shall support this command.
1100 As authentication method, only @option{Basic Authentication} (see RFC
1101 2617) is implemented so far. If no port number is given in the
1102 declaration, port @option{8080} is used for the proxy server.
1105 @item @option{socks}
1106 @cindex method socks
1107 @cindex socks method
1109 The @command{socks} method provides access to SOCKSv5 servers (see
1110 RFC 1928). @option{Username/Password Authentication} according to RFC
1113 The default port number of the socks server is @option{1080}, if not
1114 specified otherwise.
1120 @node Default Method
1121 @section Selecting a default method
1122 @cindex default method
1124 @vindex tramp-default-method
1125 When you select an appropriate transfer method for your typical usage
1126 you should set the variable @code{tramp-default-method} to reflect that
1127 choice. This variable controls which method will be used when a method
1128 is not specified in the @value{tramp} file name. For example:
1131 (setq tramp-default-method "ssh")
1134 @vindex tramp-default-method-alist
1135 You can also specify different methods for certain user/host
1136 combinations, via the variable @code{tramp-default-method-alist}. For
1137 example, the following two lines specify to use the @option{ssh}
1138 method for all user names matching @samp{john} and the @option{rsync}
1139 method for all host names matching @samp{lily}. The third line
1140 specifies to use the @option{su} method for the user @samp{root} on
1141 the machine @samp{localhost}.
1144 (add-to-list 'tramp-default-method-alist '("" "john" "ssh"))
1145 (add-to-list 'tramp-default-method-alist '("lily" "" "rsync"))
1146 (add-to-list 'tramp-default-method-alist
1147 '("\\`localhost\\'" "\\`root\\'" "su"))
1151 See the documentation for the variable
1152 @code{tramp-default-method-alist} for more details.
1154 External methods are normally preferable to inline methods, giving
1157 @xref{Inline methods}.
1158 @xref{External methods}.
1160 Another consideration with the selection of transfer methods is the
1161 environment you will use them in and, especially when used over the
1162 Internet, the security implications of your preferred method.
1164 The @option{rsh} and @option{telnet} methods send your password as
1165 plain text as you log in to the remote machine, as well as
1166 transferring the files in such a way that the content can easily be
1167 read from other machines.
1169 If you need to connect to remote systems that are accessible from the
1170 Internet, you should give serious thought to using @option{ssh} based
1171 methods to connect. These provide a much higher level of security,
1172 making it a non-trivial exercise for someone to obtain your password
1173 or read the content of the files you are editing.
1176 @subsection Which method is the right one for me?
1177 @cindex choosing the right method
1179 Given all of the above, you are probably thinking that this is all fine
1180 and good, but it's not helping you to choose a method! Right you are.
1181 As a developer, we don't want to boss our users around but give them
1182 maximum freedom instead. However, the reality is that some users would
1183 like to have some guidance, so here I'll try to give you this guidance
1184 without bossing you around. You tell me whether it works @dots{}
1186 My suggestion is to use an inline method. For large files, external
1187 methods might be more efficient, but I guess that most people will
1188 want to edit mostly small files. And if you access large text files,
1189 compression (driven by @var{tramp-inline-compress-start-size}) shall
1190 still result in good performance.
1192 I guess that these days, most people can access a remote machine by
1193 using @command{ssh}. So I suggest that you use the @option{ssh}
1194 method. So, type @kbd{C-x C-f @trampfn{ssh, root, otherhost,
1195 /etc/motd} @key{RET}} to edit the @file{/etc/motd} file on the other
1198 If you can't use @option{ssh} to log in to the remote host, then
1199 select a method that uses a program that works. For instance, Windows
1200 users might like the @option{plink} method which uses the PuTTY
1201 implementation of @command{ssh}. Or you use Kerberos and thus like
1204 For the special case of editing files on the local host as another
1205 user, see the @option{su} or @option{sudo} methods. They offer
1206 shortened syntax for the @samp{root} account, like
1207 @file{@trampfn{su, , , /etc/motd}}.
1209 People who edit large files may want to consider @option{scpc} instead
1210 of @option{ssh}, or @option{pscp} instead of @option{plink}. These
1211 external methods are faster than inline methods for large files.
1212 Note, however, that external methods suffer from some limitations.
1213 Please try first whether you really get a noticeable speed advantage
1214 from using an external method! Maybe even for large files, inline
1215 methods are fast enough.
1219 @section Selecting a default user
1220 @cindex default user
1222 The user part of a @value{tramp} file name can be omitted. Usually,
1223 it is replaced by the user name you are logged in. Often, this is not
1224 what you want. A typical use of @value{tramp} might be to edit some
1225 files with root permissions on the local host. This case, you should
1226 set the variable @code{tramp-default-user} to reflect that choice.
1230 (setq tramp-default-user "root")
1233 @code{tramp-default-user} is regarded as obsolete, and will be removed
1236 @vindex tramp-default-user-alist
1237 You can also specify different users for certain method/host
1238 combinations, via the variable @code{tramp-default-user-alist}. For
1239 example, if you always have to use the user @samp{john} in the domain
1240 @samp{somewhere.else}, you can specify the following:
1243 (add-to-list 'tramp-default-user-alist
1244 '("ssh" ".*\\.somewhere\\.else\\'" "john"))
1248 See the documentation for the variable
1249 @code{tramp-default-user-alist} for more details.
1251 One trap to fall in must be known. If @value{tramp} finds a default
1252 user, this user will be passed always to the connection command as
1253 parameter (for example @samp{ssh here.somewhere.else -l john}. If you
1254 have specified another user for your command in its configuration
1255 files, @value{tramp} cannot know it, and the remote access will fail.
1256 If you have specified in the given example in @file{~/.ssh/config} the
1260 Host here.somewhere.else
1265 than you must discard selecting a default user by @value{tramp}. This
1266 will be done by setting it to @code{nil} (or @samp{lily}, likewise):
1269 (add-to-list 'tramp-default-user-alist
1270 '("ssh" "\\`here\\.somewhere\\.else\\'" nil))
1273 The last entry in @code{tramp-default-user-alist} could be your
1274 default user you'll apply predominantly. You shall @emph{append} it
1275 to that list at the end:
1278 (add-to-list 'tramp-default-user-alist '(nil nil "jonas") t)
1283 @section Selecting a default host
1284 @cindex default host
1286 @vindex tramp-default-host
1287 Finally, it is even possible to omit the host name part of a
1288 @value{tramp} file name. This case, the value of the variable
1289 @code{tramp-default-host} is used. Per default, it is initialized
1290 with the host name your local @value{emacsname} is running.
1292 If you, for example, use @value{tramp} mainly to contact the host
1293 @samp{target} as user @samp{john}, you can specify:
1296 (setq tramp-default-user "john"
1297 tramp-default-host "target")
1300 Then the simple file name @samp{@trampfn{ssh, , ,}} will connect you
1301 to John's home directory on target.
1303 Note, however, that the most simplification @samp{/::} won't work,
1304 because @samp{/:} is the prefix for quoted file names.
1309 @section Connecting to a remote host using multiple hops
1313 Sometimes, the methods described before are not sufficient. Sometimes,
1314 it is not possible to connect to a remote host using a simple command.
1315 For example, if you are in a secured network, you might have to log in
1316 to a `bastion host' first before you can connect to the outside world.
1317 Of course, the target host may also require a bastion host.
1319 @vindex tramp-default-proxies-alist
1320 In order to specify such multiple hops, it is possible to define a proxy
1321 host to pass through, via the variable
1322 @code{tramp-default-proxies-alist}. This variable keeps a list of
1323 triples (@var{host} @var{user} @var{proxy}).
1325 The first matching item specifies the proxy host to be passed for a
1326 file name located on a remote target matching @var{user}@@@var{host}.
1327 @var{host} and @var{user} are regular expressions or @code{nil}, which
1328 is interpreted as a regular expression which always matches.
1330 @var{proxy} must be a Tramp filename which localname part is ignored.
1331 Method and user name on @var{proxy} are optional, which is interpreted
1332 with the default values.
1334 The method must be an inline or gateway method (@pxref{Inline
1335 methods}, @pxref{Gateway methods}).
1338 The method must be an inline method (@pxref{Inline methods}).
1340 If @var{proxy} is @code{nil}, no additional hop is required reaching
1341 @var{user}@@@var{host}.
1343 If you, for example, must pass the host @samp{bastion.your.domain} as
1344 user @samp{bird} for any remote host which is not located in your local
1348 (add-to-list 'tramp-default-proxies-alist
1349 '("\\." nil "@trampfn{ssh, bird, bastion.your.domain,}"))
1350 (add-to-list 'tramp-default-proxies-alist
1351 '("\\.your\\.domain\\'" nil nil))
1354 Please note the order of the code. @code{add-to-list} adds elements at the
1355 beginning of a list. Therefore, most relevant rules must be added last.
1357 Proxy hosts can be cascaded. If there is another host called
1358 @samp{jump.your.domain}, which is the only one in your local domain who
1359 is allowed connecting @samp{bastion.your.domain}, you can add another
1363 (add-to-list 'tramp-default-proxies-alist
1364 '("\\`bastion\\.your\\.domain\\'"
1366 "@trampfn{ssh, , jump.your.domain,}"))
1369 @var{proxy} can contain the patterns @code{%h} or @code{%u}. These
1370 patterns are replaced by the strings matching @var{host} or
1371 @var{user}, respectively.
1373 If you, for example, wants to work as @samp{root} on hosts in the
1374 domain @samp{your.domain}, but login as @samp{root} is disabled for
1375 non-local access, you might add the following rule:
1378 (add-to-list 'tramp-default-proxies-alist
1379 '("\\.your\\.domain\\'" "\\`root\\'" "@trampfn{ssh, , %h,}"))
1382 Opening @file{@trampfn{sudo, , randomhost.your.domain,}} would connect
1383 first @samp{randomhost.your.domain} via @code{ssh} under your account
1384 name, and perform @code{sudo -u root} on that host afterwards. It is
1385 important to know that the given method is applied on the host which
1386 has been reached so far. @code{sudo -u root}, applied on your local
1387 host, wouldn't be useful here.
1389 @var{host}, @var{user} and @var{proxy} can also be Lisp forms. These
1390 forms are evaluated, and must return a string, or @code{nil}. The
1391 previous example could be generalized then: For all hosts except my
1392 local one connect via @code{ssh} first, and apply @code{sudo -u root}
1396 (add-to-list 'tramp-default-proxies-alist
1397 '(nil "\\`root\\'" "@trampfn{ssh, , %h,}"))
1398 (add-to-list 'tramp-default-proxies-alist
1399 '((regexp-quote (system-name)) nil nil))
1402 This is the recommended configuration to work as @samp{root} on remote
1406 Finally, @code{tramp-default-proxies-alist} can be used to pass
1407 firewalls or proxy servers. Imagine your local network has a host
1408 @samp{proxy.your.domain} which is used on port 3128 as HTTP proxy to
1409 the outer world. Your friendly administrator has granted you access
1410 under your user name to @samp{host.other.domain} on that proxy
1411 server.@footnote{HTTP tunnels are intended for secure SSL/TLS
1412 communication. Therefore, many proxy server restrict the tunnels to
1413 related target ports. You might need to run your ssh server on your
1414 target host @samp{host.other.domain} on such a port, like 443 (https).
1415 See @uref{http://savannah.gnu.org/maintenance/CvsFromBehindFirewall}
1416 for discussion of ethical issues.} You would need to add the
1420 (add-to-list 'tramp-default-proxies-alist
1421 '("\\`host\\.other\\.domain\\'" nil
1422 "@trampfn{tunnel, , proxy.your.domain#3128,}"))
1425 Gateway methods can be declared as first hop only in a multiple hop
1430 @node Customizing Methods
1431 @section Using Non-Standard Methods
1432 @cindex customizing methods
1433 @cindex using non-standard methods
1434 @cindex create your own methods
1436 There is a variable @code{tramp-methods} which you can change if the
1437 predefined methods don't seem right.
1439 For the time being, I'll refer you to the Lisp documentation of that
1440 variable, accessible with @kbd{C-h v tramp-methods @key{RET}}.
1443 @node Customizing Completion
1444 @section Selecting config files for user/host name completion
1445 @cindex customizing completion
1446 @cindex selecting config files
1447 @vindex tramp-completion-function-alist
1449 The variable @code{tramp-completion-function-alist} is intended to
1450 customize which files are taken into account for user and host name
1451 completion (@pxref{Filename completion}). For every method, it keeps
1452 a set of configuration files, accompanied by a Lisp function able to
1453 parse that file. Entries in @code{tramp-completion-function-alist}
1454 have the form (@var{method} @var{pair1} @var{pair2} ...).
1456 Each @var{pair} is composed of (@var{function} @var{file}).
1457 @var{function} is responsible to extract user names and host names
1458 from @var{file} for completion. There are two functions which access
1461 @defun tramp-get-completion-function method
1462 This function returns the list of completion functions for @var{method}.
1466 (tramp-get-completion-function "rsh")
1468 @result{} ((tramp-parse-rhosts "/etc/hosts.equiv")
1469 (tramp-parse-rhosts "~/.rhosts"))
1473 @defun tramp-set-completion-function method function-list
1474 This function sets @var{function-list} as list of completion functions
1479 (tramp-set-completion-function "ssh"
1480 '((tramp-parse-sconfig "/etc/ssh_config")
1481 (tramp-parse-sconfig "~/.ssh/config")))
1483 @result{} ((tramp-parse-sconfig "/etc/ssh_config")
1484 (tramp-parse-sconfig "~/.ssh/config"))
1488 The following predefined functions parsing configuration files exist:
1491 @item @code{tramp-parse-rhosts}
1492 @findex tramp-parse-rhosts
1494 This function parses files which are syntactical equivalent to
1495 @file{~/.rhosts}. It returns both host names and user names, if
1498 @item @code{tramp-parse-shosts}
1499 @findex tramp-parse-shosts
1501 This function parses files which are syntactical equivalent to
1502 @file{~/.ssh/known_hosts}. Since there are no user names specified
1503 in such files, it can return host names only.
1505 @item @code{tramp-parse-sconfig}
1506 @findex tramp-parse-shosts
1508 This function returns the host nicknames defined by @code{Host} entries
1509 in @file{~/.ssh/config} style files.
1511 @item @code{tramp-parse-shostkeys}
1512 @findex tramp-parse-shostkeys
1514 SSH2 parsing of directories @file{/etc/ssh2/hostkeys/*} and
1515 @file{~/ssh2/hostkeys/*}. Hosts are coded in file names
1516 @file{hostkey_@var{portnumber}_@var{host-name}.pub}. User names
1517 are always @code{nil}.
1519 @item @code{tramp-parse-sknownhosts}
1520 @findex tramp-parse-shostkeys
1522 Another SSH2 style parsing of directories like
1523 @file{/etc/ssh2/knownhosts/*} and @file{~/ssh2/knownhosts/*}. This
1524 case, hosts names are coded in file names
1525 @file{@var{host-name}.@var{algorithm}.pub}. User names are always @code{nil}.
1527 @item @code{tramp-parse-hosts}
1528 @findex tramp-parse-hosts
1530 A function dedicated to @file{/etc/hosts} style files. It returns
1533 @item @code{tramp-parse-passwd}
1534 @findex tramp-parse-passwd
1536 A function which parses @file{/etc/passwd} like files. Obviously, it
1537 can return user names only.
1539 @item @code{tramp-parse-netrc}
1540 @findex tramp-parse-netrc
1542 Finally, a function which parses @file{~/.netrc} like files. This
1543 includes also @file{~/.authinfo}-style files.
1546 If you want to keep your own data in a file, with your own structure,
1547 you might provide such a function as well. This function must meet
1548 the following conventions:
1550 @defun my-tramp-parse file
1551 @var{file} must be either a file name on your host, or @code{nil}.
1552 The function must return a list of (@var{user} @var{host}), which are
1553 taken as candidates for user and host name completion.
1557 (my-tramp-parse "~/.my-tramp-hosts")
1559 @result{} ((nil "toto") ("daniel" "melancholia"))
1564 @node Password handling
1565 @section Reusing passwords for several connections.
1568 Sometimes it is necessary to connect to the same remote host several
1569 times. Reentering passwords again and again would be annoying, when
1570 the chosen method does not support access without password prompt
1571 through own configuration.
1573 The best recommendation is to use the method's own mechanism for
1574 password handling. Consider @command{ssh-agent} for @option{ssh}-like
1575 methods, or @command{pageant} for @option{plink}-like methods.
1577 However, if you cannot apply such native password handling,
1578 @value{tramp} offers altenatives.
1581 @anchor{Using an authentication file}
1582 @subsection Using an authentication file
1584 @vindex auth-sources
1585 The package @file{auth-source.el}, originally developed in No Gnus,
1586 offers the possibility to read passwords from a file, like FTP does it
1587 from @file{~/.netrc}. The default authentication file is
1588 @file{~/.authinfo.gpg}, this can be changed via the variable
1589 @code{auth-sources}.
1592 A typical entry in the authentication file would be
1595 machine melancholia port scp login daniel password geheim
1598 The port can be any @value{tramp} method (@pxref{Inline methods},
1599 @pxref{External methods}), to match only this method. When you omit
1600 the port, you match all @value{tramp} methods.
1602 In case of problems, setting @code{auth-source-debug} to @code{t}
1603 gives useful debug messages.
1606 @anchor{Caching passwords}
1607 @subsection Caching passwords
1609 If there is no authentication file, @value{tramp} caches the passwords
1610 entered by you. They will be reused next time if a connection needs
1611 them for the same user name and host name, independently of the
1614 @vindex password-cache-expiry
1615 Passwords are not saved permanently, that means the password caching
1616 is limited to the lifetime of your @value{emacsname} session. You
1617 can influence the lifetime of password caching by customizing the
1618 variable @code{password-cache-expiry}. The value is the number of
1619 seconds how long passwords are cached. Setting it to @code{nil}
1620 disables the expiration.
1622 @vindex password-cache
1623 If you don't like this feature for security reasons, password caching
1624 can be disabled totally by customizing the variable
1625 @code{password-cache} (setting it to @code{nil}).
1627 Implementation Note: password caching is based on the package
1628 @file{password-cache.el}. For the time being, it is activated only
1629 when this package is seen in the @code{load-path} while loading
1631 @ifset installchapter
1632 If you don't use No Gnus, you can take @file{password.el} from the
1633 @value{tramp} @file{contrib} directory, see @ref{Installation
1638 @node Connection caching
1639 @section Reusing connection related information.
1642 @vindex tramp-persistency-file-name
1643 In order to reduce initial connection time, @value{tramp} stores
1644 connection related information persistently. The variable
1645 @code{tramp-persistency-file-name} keeps the file name where these
1646 information are written. Its default value is
1648 @file{~/.emacs.d/tramp}.
1651 @file{~/.xemacs/tramp}.
1653 It is recommended to choose a local file name.
1655 @value{tramp} reads this file during startup, and writes it when
1656 exiting @value{emacsname}. You can simply remove this file if
1657 @value{tramp} shall be urged to recompute these information next
1658 @value{emacsname} startup time.
1660 Using such persistent information can be disabled by setting
1661 @code{tramp-persistency-file-name} to @code{nil}.
1663 Once consequence of reusing connection related information is that
1664 @var{tramp} needs to distinguish hosts. If you, for example, run a
1665 local @code{sshd} on port 3001, which tunnels @command{ssh} to another
1666 host, you could access both @file{@trampfn{ssh, , localhost,}} and
1667 @file{@trampfn{ssh, , localhost#3001,}}. @var{tramp} would use the
1668 same host related information (like paths, Perl variants, etc) for
1669 both connections, although the information is valid only for one of
1672 In order to avoid trouble, you must use another host name for one of
1673 the connections, like introducing a @option{Host} section in
1674 @file{~/.ssh/config} (@pxref{Frequently Asked Questions}) or applying
1675 multiple hops (@pxref{Multi-hops}).
1677 When @value{tramp} detects a changed operating system version on a
1678 remote host (via the command @command{uname -sr}), it flushes all
1679 connection related information for this host, and opens the
1683 @node Remote Programs
1684 @section How @value{tramp} finds and uses programs on the remote machine.
1686 @value{tramp} depends on a number of programs on the remote host in order to
1687 function, including @command{ls}, @command{test}, @command{find} and
1690 In addition to these required tools, there are various tools that may be
1691 required based on the connection method. See @ref{Inline methods} and
1692 @ref{External methods} for details on these.
1694 Certain other tools, such as @command{perl} (or @command{perl5}) and
1695 @command{grep} will be used if they can be found. When they are
1696 available, they are used to improve the performance and accuracy of
1699 @vindex tramp-remote-path
1700 @vindex tramp-default-remote-path
1701 @vindex tramp-own-remote-path
1702 @defopt tramp-remote-path
1703 When @value{tramp} connects to the remote machine, it searches for the
1704 programs that it can use. The variable @code{tramp-remote-path}
1705 controls the directories searched on the remote machine.
1707 By default, this is set to a reasonable set of defaults for most
1708 machines. The symbol @code{tramp-default-remote-path} is a place
1709 holder, it is replaced by the list of directories received via the
1710 command @command{getconf PATH} on your remote machine. For example,
1711 on Debian GNU/Linux this is @file{/bin:/usr/bin}, whereas on Solaris
1712 this is @file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin}.
1713 It is recommended to apply this symbol on top of
1714 @code{tramp-remote-path}.
1716 It is possible, however, that your local (or remote ;) system
1717 administrator has put the tools you want in some obscure local
1720 In this case, you can still use them with @value{tramp}. You simply
1721 need to add code to your @file{.emacs} to add the directory to the
1722 remote path. This will then be searched by @value{tramp} when you
1723 connect and the software found.
1725 To add a directory to the remote search path, you could use code such
1729 @i{;; We load @value{tramp} to define the variable.}
1731 @i{;; We have @command{perl} in "/usr/local/perl/bin"}
1732 (add-to-list 'tramp-remote-path "/usr/local/perl/bin")
1735 Another possibility is to reuse the path settings of your remote
1736 account when you log in. Usually, these settings are overwritten,
1737 because they might not be useful for @value{tramp}. The place holder
1738 @code{tramp-own-remote-path} preserves these settings. You can
1742 (add-to-list 'tramp-remote-path 'tramp-own-remote-path)
1746 @value{tramp} caches several information, like the Perl binary
1747 location. The changed remote search path wouldn't affect these
1748 settings. In order to force @value{tramp} to recompute these values,
1749 you must exit @value{emacsname}, remove your persistency file
1750 (@pxref{Connection caching}), and restart @value{emacsname}.
1753 @node Remote shell setup
1754 @section Remote shell setup hints
1755 @cindex remote shell setup
1756 @cindex @file{.profile} file
1757 @cindex @file{.login} file
1758 @cindex shell init files
1760 As explained in the @ref{Overview} section, @value{tramp} connects to the
1761 remote host and talks to the shell it finds there. Of course, when you
1762 log in, the shell executes its init files. Suppose your init file
1763 requires you to enter the birth date of your mother; clearly @value{tramp}
1764 does not know this and hence fails to log you in to that host.
1766 There are different possible strategies for pursuing this problem. One
1767 strategy is to enable @value{tramp} to deal with all possible situations.
1768 This is a losing battle, since it is not possible to deal with
1769 @emph{all} situations. The other strategy is to require you to set up
1770 the remote host such that it behaves like @value{tramp} expects. This might
1771 be inconvenient because you have to invest a lot of effort into shell
1772 setup before you can begin to use @value{tramp}.
1774 The package, therefore, pursues a combined approach. It tries to
1775 figure out some of the more common setups, and only requires you to
1776 avoid really exotic stuff. For example, it looks through a list of
1777 directories to find some programs on the remote host. And also, it
1778 knows that it is not obvious how to check whether a file exists, and
1779 therefore it tries different possibilities. (On some hosts and
1780 shells, the command @command{test -e} does the trick, on some hosts
1781 the shell builtin doesn't work but the program @command{/usr/bin/test
1782 -e} or @command{/bin/test -e} works. And on still other hosts,
1783 @command{ls -d} is the right way to do this.)
1785 Below you find a discussion of a few things that @value{tramp} does not deal
1786 with, and that you therefore have to set up correctly.
1789 @item @var{shell-prompt-pattern}
1790 @vindex shell-prompt-pattern
1792 After logging in to the remote host, @value{tramp} has to wait for the remote
1793 shell startup to finish before it can send commands to the remote
1794 shell. The strategy here is to wait for the shell prompt. In order to
1795 recognize the shell prompt, the variable @code{shell-prompt-pattern} has
1796 to be set correctly to recognize the shell prompt on the remote host.
1798 Note that @value{tramp} requires the match for @code{shell-prompt-pattern}
1799 to be at the end of the buffer. Many people have something like the
1800 following as the value for the variable: @code{"^[^>$][>$] *"}. Now
1801 suppose your shell prompt is @code{a <b> c $ }. In this case,
1802 @value{tramp} recognizes the @code{>} character as the end of the prompt,
1803 but it is not at the end of the buffer.
1805 @item @var{tramp-shell-prompt-pattern}
1806 @vindex tramp-shell-prompt-pattern
1808 This regular expression is used by @value{tramp} in the same way as
1809 @code{shell-prompt-pattern}, to match prompts from the remote shell.
1810 This second variable exists because the prompt from the remote shell
1811 might be different from the prompt from a local shell --- after all,
1812 the whole point of @value{tramp} is to log in to remote hosts as a
1813 different user. The default value of
1814 @code{tramp-shell-prompt-pattern} is the same as the default value of
1815 @code{shell-prompt-pattern}, which is reported to work well in many
1818 @item @var{tramp-password-prompt-regexp}
1819 @vindex tramp-password-prompt-regexp
1820 @vindex tramp-wrong-passwd-regexp
1822 During login, @value{tramp} might be forced to enter a password or a
1823 passphrase. The difference between both is that a password is
1824 requested from the shell on the remote host, while a passphrase is
1825 needed for accessing local authentication information, like your ssh
1828 @var{tramp-password-prompt-regexp} handles the detection of such
1829 requests for English environments. When you use another localization
1830 of your (local or remote) host, you might need to adapt this. Example:
1834 tramp-password-prompt-regexp
1838 '("passphrase" "Passphrase"
1840 "password" "Password"
1842 "passwort" "Passwort"
1844 "mot de passe" "Mot de passe") t)