1 \input texinfo @c -*- mode: texinfo; coding: utf-8 -*-
2 @setfilename ../../info/tramp.info
4 @settitle TRAMP User Manual
8 @c This is *so* much nicer :)
11 @c In the Tramp repository, the version number is auto-frobbed from
12 @c configure.ac, so you should edit that file and run
13 @c "autoconf && ./configure" to change the version number.
15 @include trampver.texi
17 @c Macro for formatting a file name according to the respective
18 @c syntax. Macro arguments should not have any leading or trailing
19 @c whitespace. Not very elegant, but I don't know it better.
21 @macro trampfn {method, userhost, localname}
23 \method\@value{postfixhop}@c
24 \userhost\@value{postfix}\localname\
28 Copyright @copyright{} 1999--2017 Free Software Foundation, Inc.
31 Permission is granted to copy, distribute and/or modify this document
32 under the terms of the GNU Free Documentation License, Version 1.3 or
33 any later version published by the Free Software Foundation; with no
34 Invariant Sections, with the Front-Cover Texts being ``A GNU Manual'',
35 and with the Back-Cover Texts as in (a) below. A copy of the license
36 is included in the section entitled ``GNU Free Documentation License''.
38 (a) The FSF's Back-Cover Text is: ``You have the freedom to
39 copy and modify this GNU manual.''
43 @c Entries for @command{install-info} to use
44 @dircategory Emacs network features
46 * @value{tramp}: (tramp). Transparent Remote Access, Multiple Protocol
47 Emacs remote file access via ssh and scp.
51 @title @value{tramp} version @value{trampver} User Manual
52 @author by Daniel Pittman
53 @author based on documentation by Kai Großjohann
59 @node Top, Overview, (dir), (dir)
60 @top @value{tramp} version @value{trampver} User Manual
62 This file documents @value{tramp} version @value{trampver}, a remote file
63 editing package for Emacs.
65 @value{tramp} stands for ``Transparent Remote (file) Access, Multiple
66 Protocol''. This package provides remote file editing, similar to
69 The difference is that Ange FTP uses FTP to transfer files between the
70 local and the remote host, whereas @value{tramp} uses a combination of
71 @command{rsh} and @command{rcp} or other work-alike programs, such as
72 @command{ssh}/@command{scp}.
74 You can find the latest version of this document on the web at
75 @uref{https://www.gnu.org/software/tramp/}.
78 The latest release of @value{tramp} is available for
79 @uref{https://ftp.gnu.org/gnu/tramp/, download}, or you may see
80 @ref{Obtaining @value{tramp}} for more details, including the Git
83 @value{tramp} also has a @uref{https://savannah.gnu.org/projects/tramp/,
84 Savannah Project Page}.
87 There is a mailing list for @value{tramp}, available at
88 @email{tramp-devel@@gnu.org}, and archived at
89 @uref{https://lists.gnu.org/archive/html/tramp-devel/, the
90 @value{tramp} Mail Archive}.
96 * Overview:: What @value{tramp} can and cannot do.
100 * Obtaining @value{tramp}:: How to obtain @value{tramp}.
101 * History:: History of @value{tramp}.
102 @ifset installchapter
103 * Installation:: Installing @value{tramp} with your Emacs.
105 * Quick Start Guide:: Short introduction how to use @value{tramp}.
106 * Configuration:: Configuring @value{tramp} for use.
107 * Usage:: An overview of the operation of @value{tramp}.
108 * Bug Reports:: Reporting Bugs and Problems.
109 * Frequently Asked Questions:: Questions and answers from the mailing list.
113 * Files directories and localnames::
114 How file names, directories and localnames
115 are mangled and managed.
116 * Traces and Profiles:: How to Customize Traces.
118 * GNU Free Documentation License:: The license for this documentation.
119 * Function Index:: @value{tramp} functions.
120 * Variable Index:: User options and variables.
121 * Concept Index:: An item for each concept.
124 --- The Detailed Node Listing ---
126 @ifset installchapter
127 Installing @value{tramp} with your Emacs
129 * Installation parameters:: Parameters in order to control installation.
130 * Testing:: A test suite for @value{tramp}.
131 * Load paths:: How to plug-in @value{tramp} into your environment.
134 Configuring @value{tramp} for use
136 * Connection types:: Types of connections to remote hosts.
137 * Inline methods:: Inline methods.
138 * External methods:: External methods.
139 * GVFS based methods:: GVFS based external methods.
140 * Default Method:: Selecting a default method.
141 * Default User:: Selecting a default user.
142 * Default Host:: Selecting a default host.
143 * Multi-hops:: Connecting to a remote host using multiple hops.
144 * Firewalls:: Passing firewalls.
145 * Customizing Methods:: Using Non-Standard Methods.
146 * Customizing Completion:: Selecting config files for user/host name completion.
147 * Password handling:: Reusing passwords for several connections.
148 * Connection caching:: Reusing connection related information.
149 * Predefined connection information::
150 Setting own connection related information.
151 * Remote programs:: How @value{tramp} finds and uses programs on the remote host.
152 * Remote shell setup:: Remote shell setup hints.
153 * Android shell setup:: Android shell setup hints.
154 * Auto-save and Backup:: Auto-save and Backup.
155 * Windows setup hints:: Issues with Cygwin ssh.
159 * File name syntax:: @value{tramp} file name conventions.
161 * Change file name syntax:: Alternative file name syntax.
163 * File name completion:: File name completion.
164 * Ad-hoc multi-hops:: Declaring multiple hops in the file name.
165 * Remote processes:: Integration with other Emacs packages.
166 * Cleanup remote connections:: Cleanup remote connections.
168 How file names, directories and localnames are mangled and managed
170 * Localname deconstruction:: Breaking a localname into its components.
171 * External packages:: Integration with external Lisp packages.
178 @chapter An overview of @value{tramp}
181 @value{tramp} is for transparently accessing remote files from within
182 Emacs. @value{tramp} enables an easy, convenient, and consistent
183 interface to remote files as if they are local files. @value{tramp}'s
184 transparency extends to editing, version control, and @code{dired}.
186 @value{tramp} can access remote hosts using any number of access
187 methods, such as @command{rsh}, @command{rlogin}, @command{telnet},
188 and related programs. If these programs can successfully pass
189 @acronym{ASCII} characters, @value{tramp} can use them.
190 @value{tramp} does not require or mandate 8-bit clean connections.
192 @value{tramp}'s most common access method is through @command{ssh}, a
193 more secure alternative to @command{ftp} and other older access
196 @value{tramp} on MS Windows operating systems is integrated with the
197 PuTTY package, and uses the @command{plink} program.
199 @value{tramp} mostly operates transparently in the background using
200 the connection programs. As long as these programs enable remote login
201 and can use the terminal, @value{tramp} can adapt them for seamless
202 and transparent access.
204 @value{tramp} temporarily transfers a remote file's contents to the
205 local host editing and related operations. @value{tramp} can also
206 transfer files between hosts using standard Emacs interfaces, a
207 benefit of direct integration of @value{tramp} in Emacs.
209 @value{tramp} can transfer files using any number of available host
210 programs for remote files, such as @command{rcp}, @command{scp},
211 @command{rsync} or (under MS Windows) @command{pscp}. @value{tramp}
212 provides easy ways to specify these programs and customize them to
213 specific files, hosts, or access methods.
215 For faster small-size file transfers, @value{tramp} supports encoded
216 transfers directly through the shell using @command{mimencode} or
217 @command{uuencode} provided such tools are available on the remote
221 @subsubheading @value{tramp} behind the scenes
222 @cindex behind the scenes
223 @cindex details of operation
226 Accessing a remote file through @value{tramp} entails a series of
227 actions, many of which are transparent to the user. Yet some actions
228 may require user response (such as entering passwords or completing
229 file names). One typical scenario, opening a file on a remote host, is
230 presented here to illustrate the steps involved:
232 @kbd{C-x C-f} to initiate find-file, enter part of the @value{tramp}
233 file name, then hit @kbd{@key{TAB}} for completion. If this is the
234 first time connection to that host, here's what happens:
238 @value{tramp} invokes @samp{telnet @var{host}} or @samp{rsh @var{host}
239 -l @var{user}} and establishes an external process to connect to the
240 remote host. @value{tramp} communicates with the process through an
241 Emacs buffer, which also shows output from the remote host.
244 The remote host may prompt for a login name (for @command{telnet}, for
245 example) in the buffer. If on the other hand, the login name was
246 included in the file name portion, @value{tramp} sends the login name
247 followed by a newline.
250 The remote host may then prompt for a password or pass phrase (for
251 @command{rsh} or for @command{telnet}). @value{tramp} displays the
252 password prompt in the minibuffer. @value{tramp} then sends whatever
253 is entered to the remote host, followed by a newline.
256 @value{tramp} now waits for either the shell prompt or a failed login
259 If @value{tramp} does not receive any messages within a timeout period
260 (a minute, for example), then @value{tramp} responds with an error
261 message about not finding the remote shell prompt. If any messages
262 from the remote host, @value{tramp} displays them in the buffer.
264 For any @samp{login failed} message from the remote host,
265 @value{tramp} aborts the login attempt, and repeats the login steps
269 Upon successful login and @value{tramp} recognizes the shell prompt
270 from the remote host, @value{tramp} prepares the shell environment by
271 turning off echoing, setting shell prompt, and other housekeeping
274 @strong{Note} that for the remote shell, @value{tramp} invokes
275 @command{/bin/sh}. The remote host must recognize @samp{exec /bin/sh}
276 and execute the appropriate shell. This shell must support Bourne
280 @value{tramp} executes @command{cd} and @command{ls} commands to find
281 which files exist on the remote host. @value{tramp} sometimes uses
282 @command{echo} with globbing. @value{tramp} checks if a file or
283 directory is writable with @command{test}. After each command,
284 @value{tramp} parses the output from the remote host for completing
288 After remote file name completion, @value{tramp} transfers the file
289 contents from the remote host.
291 For inline transfers, @value{tramp} sends a command, such as
292 @samp{mimencode -b /path/to/remote/file}, waits until the output has
293 accumulated in the buffer, decodes that output to produce the file's
296 For external transfers, @value{tramp} sends a command as follows:
298 rcp user@@host:/path/to/remote/file /tmp/tramp.4711
300 @value{tramp} reads the local temporary file @file{/tmp/tramp.4711}
301 into a buffer, and then deletes the temporary file.
304 Edit, modify, change the buffer contents as normal, and then save the
305 buffer wth @kbd{C-x C-s}.
308 @value{tramp} transfers the buffer contents to the remote host in
309 a reverse of the process using the appropriate inline or external
313 I hope this has provided you with a basic overview of what happens
314 behind the scenes when you open a file with @value{tramp}.
318 @node Obtaining @value{tramp}
319 @chapter Obtaining @value{tramp}
320 @cindex obtaining @value{tramp}
322 @value{tramp} is included as part of Emacs (since Emacs version 22.1).
324 @value{tramp} is also freely packaged for download on the Internet at
325 @uref{https://ftp.gnu.org/gnu/tramp/}.
327 @value{tramp} development versions are available on Git servers.
328 Development versions contain new and incomplete features.
330 One way to obtain from Git server is to visit the Savannah project
331 page at the following URL and then clicking on the Git link in the
332 navigation bar at the top.
335 @uref{https://savannah.gnu.org/projects/tramp/}
338 Another way is to follow the terminal session below:
343 $ git clone git://git.savannah.gnu.org/tramp.git
348 From behind a firewall:
352 $ git config --global http.proxy http://user:pwd@@proxy.server.com:8080
353 $ git clone https://git.savannah.gnu.org/r/tramp.git
358 @value{tramp} developers:
361 $ git clone login@@git.sv.gnu.org:/srv/git/tramp.git
365 After one of the above commands, @file{~/emacs/tramp} will
366 containing the latest version of @value{tramp}.
369 To fetch updates from the repository, use git pull:
379 Run @command{autoconf} as follows to generate an up-to-date
380 @file{configure} script:
391 @chapter History of @value{tramp}
393 @cindex development history
395 @value{tramp} development started at the end of November 1998 as
396 @file{rssh.el}. It provided only one method of access. It used
397 @command{ssh} for login and @command{scp} to transfer file contents.
398 The name was changed to @file{rcp.el} before it got its present name
399 @value{tramp}. New methods of remote access were added, so was support
402 April 2000 was the first time when multi-hop methods were added. In
403 July 2002, @value{tramp} unified file names with Ange FTP@. In July
404 2004, proxy hosts replaced multi-hop methods. Running commands on
405 remote hosts was introduced in December 2005. Support for gateways
406 since April 2007 (and removed in December 2016). GVFS integration
407 started in February 2009. Remote commands on MS Windows hosts since
408 September 2011. Ad-hoc multi-hop methods (with a changed syntax)
409 re-enabled in November 2011. In November 2012, added Juergen
410 Hoetzel's @file{tramp-adb.el}.
412 XEmacs support was stopped in January 2016. Since March 2017,
413 @value{tramp} syntax mandates a method.
415 @c Installation chapter is necessary only in case of standalone
416 @c installation. Text taken from trampinst.texi.
417 @ifset installchapter
418 @include trampinst.texi
422 @node Quick Start Guide
423 @chapter Short introduction how to use @value{tramp}
424 @cindex quick start guide
426 @value{tramp} extends the Emacs file name syntax by a remote
427 component. A remote file name looks always like
428 @file{@trampfn{method,user@@host,/path/to/file}}.
430 You can use remote files exactly like ordinary files, that means you
431 could open a file or directory by @kbd{C-x C-f
432 @trampfn{method,user@@host,/path/to/file} @key{RET}}, edit the file,
433 and save it. You can also mix local files and remote files in file
434 operations with two arguments, like @code{copy-file} or
435 @code{rename-file}. And finally, you can run even processes on a
436 remote host, when the buffer you call the process from has a remote
437 @code{default-directory}.
440 @anchor{Quick Start Guide: File name syntax}
441 @section File name syntax
442 @cindex file name syntax
444 Remote file names are prepended by the @code{method}, @code{user} and
445 @code{host} parts. All of them, and also the local file name part,
446 are optional, in case of a missing part a default value is assumed.
447 The default value for an empty local file name part is the remote
448 user's home directory. The shortest remote file name is
449 @file{@trampfn{-,,}}, therefore. The @samp{-} notation for the
450 default host is used for syntactical reasons, @ref{Default Host}.
452 The @code{method} part describes the connection method used to reach
453 the remote host, see below.
455 The @code{user} part is the user name for accessing the remote host.
456 For the @option{smb} method, this could also require a domain name, in
457 this case it is written as @code{user%domain}.
459 The @code{host} part must be a host name which could be resolved on
460 your local host. It could be a short host name, a fully qualified
461 domain name, an IPv4 or IPv6 address, @ref{File name syntax}. Some
462 connection methods support also a notation of the port to be used, in
463 this case it is written as @code{host#port}.
466 @anchor{Quick Start Guide: @option{ssh} and @option{plink} methods}
467 @section Using @option{ssh} and @option{plink}
473 If your local host runs an SSH client, and the remote host runs an SSH
474 server, the most simple remote file name is
475 @file{@trampfn{ssh,user@@host,/path/to/file}}. The remote file name
476 @file{@trampfn{ssh,,}} opens a remote connection to yourself on the
477 local host, and is taken often for testing @value{tramp}.
479 On MS Windows, PuTTY is often used as SSH client. Its @command{plink}
480 method can be used there to open a connection to a remote host running
481 an @command{ssh} server:
482 @file{@trampfn{plink,user@@host,/path/to/file}}.
485 @anchor{Quick Start Guide: @option{su}, @option{sudo} and @option{sg} methods}
486 @section Using @option{su}, @option{sudo} and @option{sg}
494 Sometimes, it is necessary to work on your local host under different
495 permissions. For this, you could use the @option{su} or @option{sudo}
496 connection method. Both methods use @samp{root} as default user name
497 and the return value of @code{(system-name)} as default host name.
498 Therefore, it is convenient to open a file as
499 @file{@trampfn{sudo,,/path/to/file}}.
501 The method @option{sg} stands for ``switch group''; the changed group
502 must be used here as user name. The default host name is the same.
505 @anchor{Quick Start Guide: @option{smb} method}
506 @section Using @command{smbclient}
509 @cindex ms windows (with smb method)
512 In order to access a remote MS Windows host or Samba server, the
513 @command{smbclient} client is used. The remote file name syntax is
514 @file{@trampfn{smb,user%domain@@host,/path/to/file}}. The first part
515 of the local file name is the share exported by the remote host,
516 @samp{path} in this example.
519 @anchor{Quick Start Guide: GVFS-based methods}
520 @section Using GVFS-based methods
521 @cindex methods, gvfs
522 @cindex gvfs based methods
532 On systems, which have installed the virtual file system for the Gnome
533 Desktop (GVFS), its offered methods could be used by @value{tramp}.
534 Examples are @file{@trampfn{sftp,user@@host,/path/to/file}},
535 @file{@trampfn{afp,user@@host,/path/to/file}} (accessing Apple's AFP
536 file system), @file{@trampfn{dav,user@@host,/path/to/file}} and
537 @file{@trampfn{davs,user@@host,/path/to/file}} (for WebDAV shares).
540 @anchor{Quick Start Guide: Google Drive}
541 @section Using Google Drive
542 @cindex method gdrive
543 @cindex gdrive method
546 Another GVFS-based method allows to access a Google Drive file system.
547 The file name syntax is here always
548 @file{@trampfn{gdrive,john.doe@@gmail.com,/path/to/file}}.
549 @samp{john.doe@@gmail.com} stands here for your Google Drive account.
552 @anchor{Quick Start Guide: Android}
553 @section Using Android
558 An Android device, which is connected via USB to your local host, can
559 be accessed via the @command{adb} command. No user or host name is
560 needed. The file name syntax is @file{@trampfn{adb,,/path/to/file}}.
564 @chapter Configuring @value{tramp}
565 @cindex configuration
566 @cindex default configuration
568 @value{tramp} is initially configured to use the @command{scp} program
569 to connect to the remote host. Just type @kbd{C-x C-f} and then enter
570 file name @file{@trampfn{scp,user@@host,/path/to/file}}. For details,
571 @xref{Default Method}, @xref{Default User}, @xref{Default Host}.
573 For problems related to the behavior of the remote shell, @xref{Remote
576 For changing the connection type and file access method from the
577 defaults to one of several other options, @xref{Connection types}.
579 @strong{Note} that some user options described in these examples are
580 not auto loaded by Emacs. All examples require @value{tramp} is
581 installed and loaded:
585 (custom-set-variables
586 '(tramp-verbose 6 nil (tramp) "Enable remote command traces"))
592 * Connection types:: Types of connections to remote hosts.
593 * Inline methods:: Inline methods.
594 * External methods:: External methods.
595 * GVFS based methods:: GVFS based external methods.
596 * Default Method:: Selecting a default method.
597 Here we also try to help those who
598 don't have the foggiest which method
600 * Default User:: Selecting a default user.
601 * Default Host:: Selecting a default host.
602 * Multi-hops:: Connecting to a remote host using multiple hops.
603 * Firewalls:: Passing firewalls.
604 * Customizing Methods:: Using Non-Standard Methods.
605 * Customizing Completion:: Selecting config files for user/host name completion.
606 * Password handling:: Reusing passwords for several connections.
607 * Connection caching:: Reusing connection related information.
608 * Predefined connection information::
609 Setting own connection related information.
610 * Remote programs:: How @value{tramp} finds and uses programs on the remote host.
611 * Remote shell setup:: Remote shell setup hints.
612 * Android shell setup:: Android shell setup hints.
613 * Auto-save and Backup:: Auto-save and Backup.
614 * Windows setup hints:: Issues with Cygwin ssh.
618 @node Connection types
619 @section Types of connections to remote hosts
620 @cindex connection types, overview
622 @dfn{Inline method} and @dfn{external method} are the two basic types
623 of access methods. While they both use the same remote shell access
624 programs, such as @command{rsh}, @command{ssh}, or @command{telnet},
625 they differ in the file access methods. Choosing the right method
626 becomes important for editing files, transferring large files, or
627 operating on a large number of files.
629 The performance of the external methods is generally better than that
630 of the inline methods, at least for large files. This is caused by
631 the need to encode and decode the data when transferring inline.
633 The one exception to this rule are the @option{scp}-based access
634 methods. While these methods do see better performance when actually
635 transferring files, the overhead of the cryptographic negotiation at
636 startup may drown out the improvement in file transfer times.
638 External methods should be configured such a way that they don't
639 require a password (with @command{ssh-agent}, or such alike). Modern
640 @command{scp} implementations offer options to reuse existing
641 @command{ssh} connections, which will be enabled by default if
642 available. If it isn't possible, you should consider @ref{Password
643 handling}, otherwise you will be prompted for a password every copy
648 @section Inline methods
649 @cindex inline methods
650 @cindex methods, inline
652 Inline methods use the same login connection to transfer file
653 contents. Inline methods are quick and easy for small files. They
654 depend on the availability of suitable encoding and decoding programs
655 on the remote host. For local source and destination, @value{tramp}
656 may use built-in equivalents of such programs in Emacs.
658 Inline methods can work in situations where an external transfer
659 program is unavailable. Inline methods also work when transferring
660 files between different @emph{user identities} on the same host.
664 @cindex base-64 encoding
666 @value{tramp} checks the remote host for the availability and
667 usability of @command{mimencode} (part of the @command{metamail}
668 package) or @command{uuencode}. @value{tramp} uses the first reliable
669 command it finds. @value{tramp}'s search path can be customized, see
670 @ref{Remote programs}.
672 In case both @command{mimencode} and @command{uuencode} are
673 unavailable, @value{tramp} first transfers a small Perl program to the
674 remote host, and then tries that program for encoding and decoding.
676 To increase transfer speeds for large text files, use compression
677 before encoding. The user option
678 @option{tramp-inline-compress-start-size} specifies the file size for
686 @command{rsh} is an option for connecting to hosts within local
687 networks since @command{rsh} is not as secure as other methods.
693 @command{ssh} is a more secure option than others to connect to a
696 @command{ssh} can also take extra parameters as port numbers. For
697 example, a host on port 42 is specified as @file{host#42} (the real
698 host name, a hash sign, then a port number). It is the same as passing
699 @samp{-p 42} to the @command{ssh} command.
701 @item @option{telnet}
702 @cindex method telnet
703 @cindex telnet method
705 Connecting to a remote host with @command{telnet} is as insecure
706 as the @option{rsh} method.
712 Instead of connecting to a remote host, @command{su} program allows
713 editing as another user. The host can be either @samp{localhost} or
714 the host returned by the function @command{(system-name)}. See
715 @ref{Multi-hops} for an exception to this behavior.
721 Similar to @option{su} method, @option{sudo} uses @command{sudo}.
722 @command{sudo} must have sufficient rights to start a shell.
728 This method is used on OpenBSD like the @command{sudo} command.
734 The @command{sg} program allows editing as different group. The host
735 can be either @samp{localhost} or the host returned by the function
736 @command{(system-name)}. The user name must be specified, but it
737 denotes a group name. See @ref{Multi-hops} for an exception to this
744 Works like @option{ssh} but without the extra authentication prompts.
745 @option{sshx} uses @samp{ssh -t -t @var{host} -l @var{user} /bin/sh}
746 to open a connection with a ``standard'' login shell.
748 @strong{Note} that @option{sshx} does not bypass authentication
749 questions. For example, if the host key of the remote host is not
750 known, @option{sshx} will still ask ``Are you sure you want to
751 continue connecting?''. @value{tramp} cannot handle such questions.
752 Connections will have to be setup where logins can proceed without
755 @option{sshx} is useful for MS Windows users when @command{ssh}
756 triggers an error about allocating a pseudo tty. This happens due to
757 missing shell prompts that confuses @value{tramp}.
759 @option{sshx} supports the @samp{-p} argument.
761 @item @option{krlogin}
762 @cindex method krlogin
763 @cindex krlogin method
764 @cindex kerberos (with krlogin method)
766 This method is also similar to @option{ssh}. It uses the
767 @command{krlogin -x} command only for remote host login.
772 @cindex kerberos (with ksu method)
774 This is another method from the Kerberos suite. It behaves like @option{su}.
780 @option{plink} method is for MS Windows users with the PuTTY
781 implementation of SSH@. It uses @samp{plink -ssh} to log in to the
784 Check the @samp{Share SSH connections if possible} control for that
787 @option{plink} method supports the @samp{-P} argument.
789 @item @option{plinkx}
790 @cindex method plinkx
791 @cindex plinkx method
793 Another method using PuTTY on MS Windows with session names instead of
794 host names. @option{plinkx} calls @samp{plink -load @var{session}
795 -t}. User names and port numbers must be defined in the session.
797 Check the @samp{Share SSH connections if possible} control for that
803 @node External methods
804 @section External methods
805 @cindex methods, external
806 @cindex external methods
808 External methods operate over multiple channels, using the remote
809 shell connection for some actions while delegating file transfers to
810 an external transfer program.
812 External methods save on the overhead of encoding and decoding of
815 Since external methods have the overhead of opening a new channel,
816 files smaller than @var{tramp-copy-size-limit} still use inline
823 @cindex rcp (with rcp method)
824 @cindex rsh (with rcp method)
826 This method uses the @command{rsh} and @command{rcp} commands to
827 connect to the remote host and transfer files. This is the fastest
828 access method available.
830 The alternative method @option{remcp} uses the @command{remsh} and
831 @command{rcp} commands.
836 @cindex scp (with scp method)
837 @cindex ssh (with scp method)
839 Using a combination of @command{ssh} to connect and @command{scp} to
840 transfer is the most secure. While the performance is good, it is
841 slower than the inline methods for smaller files. Though there is no
842 overhead of encoding and decoding of the inline methods,
843 @command{scp}'s cryptographic handshake negates those speed gains.
845 @option{ssh}-based methods support @samp{-p} feature for specifying
846 port numbers. For example, @file{host#42} passes @samp{-p 42} in the
847 argument list to @command{ssh}, and @samp{-P 42} in the argument list
853 @cindex rsync (with rsync method)
854 @cindex ssh (with rsync method)
856 @command{ssh} command to connect in combination with @command{rsync}
857 command to transfer is similar to the @option{scp} method.
859 @command{rsync} performs much better than @command{scp} when
860 transferring files that exist on both hosts. However, this advantage
861 is lost if the file exists only on one side of the connection.
863 This method supports the @samp{-p} argument.
868 @cindex scp (with scpx method)
869 @cindex ssh (with scpx method)
871 @option{scpx} is useful to avoid login shell questions. It is similar
872 in performance to @option{scp}. @option{scpx} uses @samp{ssh -t -t
873 @var{host} -l @var{user} /bin/sh} to open a connection.
875 @option{scpx} is useful for MS Windows users when @command{ssh}
876 triggers an error about allocating a pseudo tty. This happens due to
877 missing shell prompts that confuses @value{tramp}.
879 This method supports the @samp{-p} argument.
885 @cindex pscp (with pscp method)
886 @cindex plink (with pscp method)
887 @cindex putty (with pscp method)
890 @cindex pscp (with psftp method)
891 @cindex plink (with psftp method)
892 @cindex putty (with psftp method)
894 These methods are similar to @option{scp} or @option{sftp}, but they
895 use the @command{plink} command to connect to the remote host, and
896 they use @command{pscp} or @command{psftp} for transferring the files.
897 These programs are part of PuTTY, an SSH implementation for MS Windows.
899 Check the @samp{Share SSH connections if possible} control for that
902 These methods support the @samp{-P} argument.
907 @cindex fsh (with fcp method)
908 @cindex fcp (with fcp method)
910 This method is similar to @option{scp}, but uses @command{fsh} to
911 connect and @command{fcp} to transfer files. @command{fsh/fcp}, a
912 front-end for @command{ssh}, reuse @command{ssh} session by
913 submitting several commands. This avoids the startup overhead due to
914 @command{scp}'s secure connection. Inline methods have similar
917 The command used for this connection is: @samp{fsh @var{host} -l
918 @var{user} /bin/sh -i}
923 @option{fsh} has no inline method since the multiplexing it offers is
924 not useful for @value{tramp}. @command{fsh} connects to remote host
925 and @value{tramp} keeps that one connection open.
930 @cindex nc (with nc method)
931 @cindex telnet (with nc method)
933 Using @command{telnet} to connect and @command{nc} to transfer files
934 is sometimes the only combination suitable for accessing routers or
935 NAS hosts. These dumb devices have severely restricted local shells,
936 such as the @command{busybox} and do not host any other encode or
943 When @value{tramp} uses @option{ftp}, it forwards requests to whatever
944 ftp program is specified by Ange FTP. This external program must be
945 capable of servicing requests from @value{tramp}.
950 @cindex ms windows (with smb method)
953 This non-native @value{tramp} method connects via the Server Message
954 Block (SMB) networking protocol to hosts running file servers that are
955 typically based on @url{https://www.samba.org/,,Samba} or MS Windows.
957 Using @command{smbclient} requires a few tweaks when working with
960 The first directory in the localname must be a share name on the
963 Since some SMB share names end in the @code{$} character,
964 @value{tramp} must use @code{$$} when specifying those shares to avoid
965 environment variable substitutions.
967 When @value{tramp} is not specific about the share name or uses the
968 generic remote directory @file{/}, @command{smbclient} returns all
971 Since SMB authentication is based on each SMB share, @value{tramp}
972 prompts for a password even when accessing a different share on the
973 same SMB host. This prompting can be suppressed by @ref{Password
976 To accommodate user name/domain name syntax required by MS Windows
977 authorization, @value{tramp} provides for an extended syntax in
978 @code{user%domain} format (where @code{user} is the user name,
979 @code{%} is the percent symbol, and @code{domain} is the MS Windows
980 domain name). An example:
983 @trampfn{smb,daniel%BIZARRE@@melancholia,/daniel$$/.emacs}
986 where user @code{daniel} connects as a domain user to the SMB host
987 @code{melancholia} in the MS Windows domain @code{BIZARRE} to edit
988 @file{.emacs} located in the home directory (share @code{daniel$}).
990 Alternatively, for local WINS users (as opposed to domain users),
991 substitute the domain name with the name of the local host in
992 UPPERCASE as shown here:
995 @trampfn{smb,daniel%MELANCHOLIA@@melancholia,/daniel$$/.emacs}
998 where user @code{daniel} connects as local user to the SMB host
999 @code{melancholia} in the local domain @code{MELANCHOLIA} to edit
1000 @file{.emacs} located in the home directory (share @code{daniel$}).
1002 The domain name and user name are optional for @command{smbclient}
1003 authentication. When user name is not specified, @command{smbclient}
1004 uses the anonymous user (without prompting for password). This
1005 behavior is unlike other @value{tramp} methods, where local user name
1008 The @option{smb} method is unavailable if Emacs is run under a local
1009 user authentication context in MS Windows. However such users can
1010 still access remote files using UNC file names instead of @value{tramp}:
1013 //melancholia/daniel$$/.emacs
1016 UNC file name specification does not allow the specification of a
1017 different user name for authentication like the @command{smbclient}
1024 @cindex android (with adb method)
1026 This method uses Android Debug Bridge program for accessing Android
1027 devices. The Android Debug Bridge must be installed locally for
1028 @value{tramp} to work. Some GNU/Linux distributions provide Android
1029 Debug Bridge as an installation package. Alternatively, the program
1030 is installed as part of the Android SDK@. @value{tramp} finds the
1031 @command{adb} program either via the @env{PATH} environment variable
1032 or the absolute path set in the user option @option{tramp-adb-program}.
1034 @value{tramp} connects to Android devices with @option{adb} only when
1035 the user option @option{tramp-adb-connect-if-not-connected} is not
1036 @code{nil}. Otherwise, the connection must be established outside
1039 @value{tramp} does not require a host name part of the remote file
1040 name when a single Android device is connected to @command{adb}.
1041 @value{tramp} instead uses @file{@trampfn{adb,,}} as the default name.
1042 @command{adb devices} shows available host names.
1044 @option{adb} method normally does not need user name to authenticate
1045 on the Android device because it runs under the @command{adbd}
1046 process. But when a user name is specified, however, @value{tramp}
1047 applies an @command{su} in the syntax. When authentication does not
1048 succeed, especially on un-rooted Android devices, @value{tramp}
1049 displays login errors.
1051 For Android devices connected through TCP/IP, a port number can be
1052 specified using @file{device#42} host name syntax or @value{tramp} can
1053 use the default value as declared in @command{adb} command. Port
1054 numbers are not applicable to Android devices connected through USB@.
1059 @node GVFS based methods
1060 @section GVFS based external methods
1061 @cindex methods, gvfs
1062 @cindex gvfs based methods
1065 GVFS is the virtual file system for the Gnome Desktop,
1066 @uref{https://en.wikipedia.org/wiki/GVFS}. Remote files on GVFS are
1067 mounted locally through FUSE and @value{tramp} uses this locally
1068 mounted directory internally.
1070 Emacs uses the D-Bus mechanism to communicate with GVFS@. Emacs must
1071 have the message bus system, D-Bus integration active, @pxref{Top, ,
1079 This method is for connecting to remote hosts with the Apple Filing
1080 Protocol for accessing files on macOS volumes. @value{tramp} access
1081 syntax requires a leading volume (share) name, for example:
1082 @file{@trampfn{afp,user@@host,/volume}}.
1091 @option{dav} method provides access to WebDAV files and directories
1092 based on standard protocols, such as HTTP@. @option{davs} does the same
1093 but with SSL encryption. Both methods support the port numbers.
1095 @item @option{gdrive}
1096 @cindex method gdrive
1097 @cindex gdrive method
1098 @cindex google drive
1100 Via the @option{gdrive} method it is possible to access your Google
1101 Drive online storage. User and host name of the remote file name are
1102 your email address of the Google Drive credentials, like
1103 @file{@trampfn{gdrive,john.doe@@gmail.com,/}}. These credentials must
1104 be populated in your @command{Online Accounts} application outside Emacs.
1106 Since Google Drive uses cryptic blob file names internally,
1107 @value{tramp} works with the @code{display-name} of the files. This
1108 could produce unexpected behavior in case two files in the same
1109 directory have the same @code{display-name}, such a situation must be avoided.
1115 OBEX is an FTP-like access protocol for cell phones and similar simple
1116 devices. @value{tramp} supports OBEX over Bluetooth.
1122 This method uses @command{sftp} in order to securely access remote
1123 hosts. @command{sftp} is a more secure option for connecting to hosts
1124 that for security reasons refuse @command{ssh} connections.
1126 @item @option{synce}
1127 @cindex method synce
1128 @cindex synce method
1130 @option{synce} method allows connecting to MS Windows Mobile devices.
1131 It uses GVFS for mounting remote files and directories via FUSE and
1132 requires the SYNCE-GVFS plugin.
1136 @defopt tramp-gvfs-methods
1137 This user option is a list of external methods for GVFS@. By default,
1138 this list includes @option{afp}, @option{dav}, @option{davs},
1139 @option{gdrive}, @option{obex}, @option{sftp} and @option{synce}.
1140 Other methods to include are: @option{ftp} and @option{smb}.
1144 @node Default Method
1145 @section Selecting a default method
1146 @cindex default method
1148 In a remote file name, the use of a default method is indicated by the
1149 pseudo method @option{-}, @ref{File name syntax}.
1151 @defopt tramp-default-method
1152 Default method is for transferring files. The user option
1153 @option{tramp-default-method} sets it. @value{tramp} uses this user
1154 option to determine the default method for remote file names that do
1155 not have one specified.
1158 (custom-set-variables '(tramp-default-method "ssh" nil (tramp)))
1162 @defopt tramp-default-method-alist
1163 Default methods for transferring files can be customized for specific
1164 user and host combinations through the user option
1165 @option{tramp-default-method-alist}.
1167 For example, the following two lines specify to use the @option{ssh}
1168 method for all user names matching @samp{john} and the @option{rsync}
1169 method for all host names matching @samp{lily}. The third line
1170 specifies to use the @option{su} method for the user @samp{root} on
1171 the host @samp{localhost}.
1175 (add-to-list 'tramp-default-method-alist '("" "john" "ssh"))
1176 (add-to-list 'tramp-default-method-alist '("lily" "" "rsync"))
1177 (add-to-list 'tramp-default-method-alist
1178 '("\\`localhost\\'" "\\`root\\'" "su"))
1184 External methods performance faster for large files. @pxref{Inline
1185 methods}. @pxref{External methods}.
1187 Choosing the access method also depends on the security environment.
1188 For example, @option{rsh} and @option{telnet} methods that use clear
1189 text password transfers are inappropriate for over the Internet
1190 connections. Secure remote connections should use @option{ssh} that
1194 @subsection Which method to use?
1195 @cindex choosing the right method
1197 @value{tramp} provides maximum number of choices for maximum
1198 flexibility. Choosing which method depends on the hosts, clients,
1199 network speeds, and the security context.
1201 Start by using an inline method.
1203 External methods might be more efficient for large files, but most
1204 @value{tramp} users edit small files more often than large files.
1206 Enable compression, @var{tramp-inline-compress-start-size}, for a
1207 performance boost for large files.
1209 Since @command{ssh} has become the most common method of remote host
1210 access and it has the most reasonable security protocols, use
1211 @option{ssh} method. Typical @option{ssh} usage to edit the
1212 @file{/etc/motd} file on the otherhost:
1215 @kbd{C-x C-f @trampfn{ssh,root@@otherhost,/etc/motd} @key{RET}}
1218 If @option{ssh} is unavailable for whatever reason, look for other
1219 obvious options. For MS Windows, try the @option{plink} method. For
1220 Kerberos, try @option{krlogin}.
1222 For editing local files as @option{su} or @option{sudo} methods, try
1223 the shortened syntax of @samp{root}:
1226 @kbd{C-x C-f @trampfn{su,,/etc/motd} @key{RET}}
1229 For editing large files, @option{scp} is faster than @option{ssh}.
1230 @option{pscp} is faster than @option{plink}. But this speed
1231 improvement is not always true.
1235 @section Selecting a default user
1236 @cindex default user
1238 @defopt tramp-default-user
1239 @value{tramp} file name can omit the user name part since
1240 @value{tramp} substitutes the currently logged-in user name. However
1241 this substitution can be overridden with @option{tramp-default-user}.
1245 (custom-set-variables'(tramp-default-user "root" nil (tramp)))
1249 @defopt tramp-default-user-alist
1250 Instead of a single default user, @option{tramp-default-user-alist}
1251 allows multiple default user values based on access method or host
1252 name combinations. The alist can hold multiple values. For example, to
1253 use the @samp{john} as the default user for the domain
1254 @samp{somewhere.else} only:
1258 (add-to-list 'tramp-default-user-alist
1259 '("ssh" ".*\\.somewhere\\.else\\'" "john"))
1263 A Caution: @value{tramp} will override any default user specified in
1264 the configuration files outside Emacs, such as @file{~/.ssh/config}.
1265 To stop @value{tramp} from applying the default value, set the
1266 corresponding alist entry to nil:
1270 (add-to-list 'tramp-default-user-alist
1271 '("ssh" "\\`here\\.somewhere\\.else\\'" nil))
1275 The last entry in @option{tramp-default-user-alist} should be reserved
1276 for catch-all or most often used login.
1280 (add-to-list 'tramp-default-user-alist
1281 '(nil nil "jonas") t)
1288 @section Selecting a default host
1289 @cindex default host
1291 @defopt tramp-default-host
1292 When host name is omitted, @value{tramp} substitutes the value from
1293 the @option{tramp-default-host} user option. It is initially
1294 populated with the local host name where Emacs is running. The
1295 default method, default user and default host can be overridden as
1300 (custom-set-variables
1301 '(tramp-default-method "ssh" nil (tramp))
1302 '(tramp-default-user "john" nil (tramp))
1303 '(tramp-default-host "target" nil (tramp)))
1307 With all defaults set, @samp{@trampfn{-,,}} will connect @value{tramp}
1308 to John's home directory on @code{target} via @code{ssh}.
1311 @defopt tramp-default-host-alist
1312 Instead of a single default host, @option{tramp-default-host-alist}
1313 allows multiple default host values based on access method or user
1314 name combinations. The alist can hold multiple values. While
1315 @option{tramp-default-host} is sufficient in most cases, some methods,
1316 like @option{adb}, require defaults overwritten.
1321 @section Connecting to a remote host using multiple hops
1325 Multi-hops are methods to reach hosts behind firewalls or to reach the
1326 outside world from inside a bastion host. With multi-hops,
1327 @value{tramp} can negotiate these hops with the appropriate user/host
1328 authentication at each hop. All methods until now have been the single
1329 hop kind, where the start and end points of the connection did not
1330 have intermediate check points.
1332 @defopt tramp-default-proxies-alist
1333 @option{tramp-default-proxies-alist} specifies proxy hosts to pass
1334 through. This user option is list of triples consisting of
1335 @code{(@var{host} @var{user} @var{proxy})}.
1337 The first match is the proxy host through which passes the file name
1338 and the target host matching @var{user}@@@var{host}. @var{host} and
1339 @var{user} are regular expressions or @code{nil}, interpreted as a
1340 regular expression which always matches.
1342 @var{proxy} is a literal @value{tramp} file name whose local name part
1343 is ignored, and the method and user name parts are optional.
1345 The method must be an inline method (@pxref{Inline methods}). If
1346 @var{proxy} is @code{nil}, no additional hop is required reaching
1347 @var{user}@@@var{host}.
1349 For example, to pass through the host @samp{bastion.your.domain} as
1350 user @samp{bird} to reach remote hosts outside the local domain:
1354 (add-to-list 'tramp-default-proxies-alist
1355 '("\\." nil "@trampfn{ssh,bird@@bastion.your.domain,}"))
1356 (add-to-list 'tramp-default-proxies-alist
1357 '("\\.your\\.domain\\'" nil nil))
1361 @strong{Note}: @code{add-to-list} adds elements at the beginning of a
1362 list. Therefore, most relevant rules must come last in the list.
1364 Proxy hosts can be cascaded in the alist. If there is another host
1365 called @samp{jump.your.domain}, which is the only host allowed to
1366 connect to @samp{bastion.your.domain}, then:
1370 (add-to-list 'tramp-default-proxies-alist
1371 '("\\`bastion\\.your\\.domain\\'"
1373 "@trampfn{ssh,jump.your.domain,}"))
1377 @var{proxy} can take patterns @code{%h} or @code{%u} for @var{host} or
1378 @var{user} respectively.
1380 To login as @samp{root} on remote hosts in the domain
1381 @samp{your.domain}, but login as @samp{root} is disabled for non-local
1382 access, then use this alist entry:
1386 (add-to-list 'tramp-default-proxies-alist
1387 '("\\.your\\.domain\\'" "\\`root\\'" "@trampfn{ssh,%h,}"))
1391 Opening @file{@trampfn{sudo,randomhost.your.domain,}} first connects
1392 to @samp{randomhost.your.domain} via @code{ssh} under your account
1393 name, and then performs @code{sudo -u root} on that host.
1395 It is key for the sudo method in the above example to be applied on
1396 the host after reaching it and not on the local host.
1398 @var{host}, @var{user} and @var{proxy} can also take Lisp forms. These
1399 forms when evaluated must return either a string or @code{nil}.
1401 To generalize (from the previous example): For all hosts, except my
1402 local one, first connect via @command{ssh}, and then apply
1403 @command{sudo -u root}:
1407 (add-to-list 'tramp-default-proxies-alist
1408 '(nil "\\`root\\'" "@trampfn{ssh,%h,}"))
1409 (add-to-list 'tramp-default-proxies-alist
1410 '((regexp-quote (system-name)) nil nil))
1415 Passing through hops involves dealing with restricted shells, such as
1416 @command{rbash}. If @value{tramp} is made aware, then it would use
1417 them for proxies only.
1419 @defopt tramp-restricted-shell-hosts-alist
1420 An alist of regular expressions of hosts running restricted shells,
1421 such as @command{rbash}. @value{tramp} will then use them only as
1424 To specify the bastion host from the example above as running a
1429 (add-to-list 'tramp-restricted-shell-hosts-alist
1430 "\\`bastion\\.your\\.domain\\'")
1437 @section Passing firewalls
1439 @cindex proxy hosts, http tunnel
1441 Sometimes, it is not possible to reach a remote host directly. A
1442 firewall might be in the way, which could be passed via a proxy
1445 Both ssh and PuTTY support such proxy settings, using an HTTP tunnel
1446 via the @command{CONNECT} command (conforming to RFC 2616, 2817
1447 specifications). Proxy servers using HTTP version 1.1 or later
1448 protocol support this command.
1450 @subsection Tunneling with ssh
1452 With ssh, you could use the @code{ProxyCommand} entry in the
1453 @file{~/.ssh/config}:
1457 Host host.other.domain
1458 ProxyCommand nc -X connect -x proxy.your.domain:3128 %h %p
1462 @code{nc} is BSD's netcat program, which establishes HTTP tunnels. Any
1463 other program with such a feature could be used as well.
1465 In the example, opening @file{@trampfn{ssh,host.your.domain,}} passes
1466 the HTTP proxy server @samp{proxy.your.domain} on port 3128.
1468 @subsection Tunneling with PuTTY
1470 PuTTY does not need an external program, HTTP tunnel support is
1471 built-in. In the PuTTY config program, create a session for
1472 @samp{host.your.domain}. In the @option{Connection/Data} entry,
1473 select the @option{HTTP} option, and add @samp{proxy.your.domain} as
1474 @option{Proxy hostname}, and 3128 as @option{Port}.
1476 Opening @file{@trampfn{plinkx,host.your.domain,}} passes the HTTP
1477 proxy server @samp{proxy.your.domain} on port 3128.
1480 @node Customizing Methods
1481 @section Using Non-Standard Methods
1482 @cindex customizing methods
1483 @cindex using non-standard methods
1484 @cindex create your own methods
1486 The @code{tramp-methods} variable currently has an exhaustive list of
1487 predefined methods. Any part of this list can be modified with more
1488 suitable settings. Refer to the Lisp documentation of that variable,
1489 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 @code{tramp-completion-function-alist} uses predefined files for user
1499 and host name completion (@pxref{File name completion}). For each
1500 method, it keeps a set of configuration files and a function that can
1501 parse that file. Each entry in @code{tramp-completion-function-alist}
1502 is of the form (@var{method} @var{pair1} @var{pair2} @dots{}).
1504 Each @var{pair} is composed of (@var{function} @var{file}).
1505 @var{function} is responsible for extracting user names and host names
1506 from @var{file} for completion. There are two functions which access
1509 @defun tramp-get-completion-function method
1510 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"))
1523 @defun tramp-set-completion-function method function-list
1524 This function sets @var{function-list} as list of completion functions
1530 (tramp-set-completion-function "ssh"
1531 '((tramp-parse-sconfig "/etc/ssh_config")
1532 (tramp-parse-sconfig "~/.ssh/config")))
1534 @result{} ((tramp-parse-sconfig "/etc/ssh_config")
1535 (tramp-parse-sconfig "~/.ssh/config"))
1540 The following predefined functions parsing configuration files exist:
1543 @item @code{tramp-parse-rhosts}
1544 @findex tramp-parse-rhosts
1546 This function parses files which are syntactical equivalent to
1547 @file{~/.rhosts}. It returns both host names and user names, if
1550 @item @code{tramp-parse-shosts}
1551 @findex tramp-parse-shosts
1553 This function parses files which are syntactical equivalent to
1554 @file{~/.ssh/known_hosts}. Since there are no user names specified
1555 in such files, it can return host names only.
1557 @item @code{tramp-parse-sconfig}
1558 @findex tramp-parse-sconfig
1560 This function returns the host nicknames defined by @code{Host} entries
1561 in @file{~/.ssh/config} style files.
1563 @item @code{tramp-parse-shostkeys}
1564 @findex tramp-parse-shostkeys
1566 SSH2 parsing of directories @file{/etc/ssh2/hostkeys/*} and
1567 @file{~/ssh2/hostkeys/*}. Hosts are coded in file names
1568 @file{hostkey_@var{portnumber}_@var{host-name}.pub}. User names
1569 are always @code{nil}.
1571 @item @code{tramp-parse-sknownhosts}
1572 @findex tramp-parse-sknownhosts
1574 Another SSH2 style parsing of directories like
1575 @file{/etc/ssh2/knownhosts/*} and @file{~/ssh2/knownhosts/*}. This
1576 case, hosts names are coded in file names
1577 @file{@var{host-name}.@var{algorithm}.pub}. User names are always @code{nil}.
1579 @item @code{tramp-parse-hosts}
1580 @findex tramp-parse-hosts
1582 A function dedicated to @file{/etc/hosts} for host names.
1584 @item @code{tramp-parse-passwd}
1585 @findex tramp-parse-passwd
1587 A function which parses @file{/etc/passwd} files for user names.
1589 @item @code{tramp-parse-etc-group}
1590 @findex tramp-parse-etc-group
1592 A function which parses @file{/etc/group} files for group names.
1594 @item @code{tramp-parse-netrc}
1595 @findex tramp-parse-netrc
1597 A function which parses @file{~/.netrc} and @file{~/.authinfo}-style files.
1601 To keep a custom file with custom data in a custom structure, a custom
1602 function has to be provided. This function must meet the following
1605 @defun my-tramp-parse file
1606 @var{file} must be either a file on the host, or @code{nil}. The
1607 function must return a list of (@var{user} @var{host}), which are
1608 taken as candidates for completion for user and host names.
1613 (my-tramp-parse "~/.my-tramp-hosts")
1615 @result{} ((nil "toto") ("daniel" "melancholia"))
1621 @node Password handling
1622 @section Reusing passwords for several connections
1625 To avoid repeated prompts for passwords, consider native caching
1626 mechanisms, such as @command{ssh-agent} for @option{ssh}-like
1627 methods, or @command{pageant} for @option{plink}-like methods.
1629 @value{tramp} offers alternatives when native solutions cannot meet
1633 @anchor{Using an authentication file}
1634 @subsection Using an authentication file
1635 @vindex auth-sources
1637 The package @file{auth-source.el}, originally developed for No Gnus,
1638 reads passwords from different sources, @xref{Help for users, ,
1639 auth-source, auth}. The default authentication file is
1640 @file{~/.authinfo.gpg}, but this can be changed via the variable
1641 @code{auth-sources}.
1644 A typical entry in the authentication file:
1647 machine melancholia port scp login daniel password geheim
1650 The port can take any @value{tramp} method (@pxref{Inline methods},
1651 @pxref{External methods}). Omitting port values matches all
1652 @value{tramp} methods. Domain and ports, as used in @value{tramp}
1653 file name syntax, must be appended to the machine and login items:
1656 machine melancholia#4711 port davs login daniel%BIZARRE password geheim
1659 @vindex auth-source-debug
1660 Set @code{auth-source-debug} to @code{t} to debug messages.
1663 @anchor{Caching passwords}
1664 @subsection Caching passwords
1666 @value{tramp} can cache passwords as entered and reuse when needed for
1667 the same user or host name independent of the access method.
1669 @vindex password-cache-expiry
1670 @code{password-cache-expiry} sets the duration (in seconds) the
1671 passwords are remembered. Passwords are never saved permanently nor
1672 can they extend beyond the lifetime of the current Emacs session. Set
1673 @code{password-cache-expiry} to @code{nil} to disable expiration.
1675 @vindex password-cache
1676 Set @code{password-cache} to @code{nil} to disable password caching.
1679 @node Connection caching
1680 @section Reusing connection related information
1682 @vindex tramp-persistency-file-name
1684 For faster initial connection times, @value{tramp} stores previous
1685 connection properties in a file specified by the user option
1686 @option{tramp-persistency-file-name}.
1688 The default file name for @option{tramp-persistency-file-name} is
1689 @file{~/.emacs.d/tramp}.
1691 @value{tramp} reads this file during Emacs startup, and writes to it
1692 when exiting Emacs. Delete this file for @value{tramp} to recreate a
1693 new one on next Emacs startup.
1695 Set @option{tramp-persistency-file-name} to @code{nil} to disable
1696 storing connections persistently.
1698 When @value{tramp} detects a change in the operating system version in
1699 a remote host (via the command @command{uname -sr}), it flushes all
1700 connection related information for that host and creates a new entry.
1703 @node Predefined connection information
1704 @section Setting own connection related information
1705 @vindex tramp-connection-properties
1707 For more precise customization, parameters specified by
1708 @code{tramp-methods} can be overwritten manually.
1710 Set @option{tramp-connection-properties} to manually override
1711 @code{tramp-methods}. Properties in this list are in the form
1712 @code{(@var{regexp} @var{property} @var{value})}. @var{regexp}
1713 matches remote file names. Use @code{nil} to match all.
1714 @var{property} is the property's name, and @var{value} is the
1717 @var{property} is any method specific parameter contained in
1718 @code{tramp-methods}. The parameter key in @code{tramp-methods} is a
1719 symbol name @code{tramp-<foo>}. To overwrite that property, use the
1720 string @samp{<foo>} for @var{property}. For example, this changes the
1725 (add-to-list 'tramp-connection-properties
1726 (list (regexp-quote "@trampfn{ssh,user@@randomhost.your.domain,}")
1727 "remote-shell" "/bin/ksh"))
1731 (add-to-list 'tramp-connection-properties
1732 (list (regexp-quote "@trampfn{ssh,user@@randomhost.your.domain,}")
1733 "remote-shell-login" '("-")))
1737 The parameters @code{tramp-remote-shell} and
1738 @code{tramp-remote-shell-login} in @code{tramp-methods} now have new
1739 values for the remote host.
1741 @var{property} could also be any property found in
1742 @option{tramp-persistency-file-name}.
1744 To get around how restricted shells randomly drop connections, set the
1745 special property @samp{busybox}. For example:
1749 (add-to-list 'tramp-connection-properties
1750 (list (regexp-quote "@trampfn{ssh,user@@randomhost.your.domain,}")
1756 @node Remote programs
1757 @section How @value{tramp} finds and uses programs on the remote host
1759 @value{tramp} requires access to and rights to several commands on
1760 remote hosts: @command{ls}, @command{test}, @command{find} and
1763 Besides there are other required programs for @ref{Inline methods} and
1764 @ref{External methods} of connection.
1766 To improve performance and accuracy of remote file access,
1767 @value{tramp} uses @command{perl} (or @command{perl5}) and
1768 @command{grep} when available.
1770 @defopt tramp-remote-path
1771 @option{tramp-remote-path} specifies which remote directory paths
1772 @value{tramp} can search for @ref{Remote programs}.
1774 @vindex tramp-default-remote-path
1775 @value{tramp} uses standard defaults, such as @file{/bin} and
1776 @file{/usr/bin}, which are reasonable for most hosts. To accommodate
1777 differences in hosts and paths, for example, @file{/bin:/usr/bin} on
1779 @file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin} on
1780 Solaris, @value{tramp} queries the remote host with @command{getconf
1781 PATH} and updates the symbol @code{tramp-default-remote-path}.
1783 For instances where hosts keep obscure locations for paths for
1784 security reasons, manually add such paths to local @file{.emacs} as
1785 shown below for @value{tramp} to use when connecting.
1788 (add-to-list 'tramp-remote-path "/usr/local/perl/bin")
1791 @vindex tramp-own-remote-path
1792 Another way to find the remote path is to use the path assigned to the
1793 remote user by the remote host. @value{tramp} does not normally retain
1794 this remote path after login. However, @code{tramp-own-remote-path}
1795 preserves the path value, which can be used to update
1796 @option{tramp-remote-path}.
1799 (add-to-list 'tramp-remote-path 'tramp-own-remote-path)
1802 @strong{Note} that this works only if your remote @command{/bin/sh}
1803 shell supports the login argument @samp{-l}.
1806 When remote search paths are changed, local @value{tramp} caches must
1807 be recomputed. To force @value{tramp} to recompute afresh, exit
1808 Emacs, remove the persistent file (@pxref{Connection caching}), and
1812 @node Remote shell setup
1813 @section Remote shell setup hints
1814 @cindex remote shell setup
1815 @cindex @file{.profile} file
1816 @cindex @file{.login} file
1817 @cindex shell init files
1819 @value{tramp} checks for the availability of standard programs in the
1820 usual locations. Common tactics include successively trying
1821 @command{test -e}, @command{/usr/bin/test -e}, and @command{/bin/test
1822 -e}. @command{ls -d} is another approach. But these approaches do not
1823 help with these new login patterns.
1825 When @value{tramp} encounters two-factor logins or additional challenge
1826 questions, such as entering birth date or security code or passphrase,
1827 @value{tramp} needs a few more configuration steps to accommodate
1830 The difference between a password prompt and a passphrase prompt is
1831 that the password for completing the login while the passphrase is
1832 for authorizing access to local authentication information, such as
1835 There is no one configuration to accommodate all the variations in
1836 login security, especially not the exotic ones. However, @value{tramp}
1837 provides a few tweaks to address the most common ones.
1840 @item @option{tramp-shell-prompt-pattern}
1841 @vindex tramp-shell-prompt-pattern
1843 @option{tramp-shell-prompt-pattern} is for remote login shell prompt,
1844 which may not be the same as the local login shell prompt,
1845 @code{shell-prompt-pattern}. Since most hosts use identical prompts,
1846 @value{tramp} sets a similar default value for both prompts.
1848 @item @option{tramp-password-prompt-regexp}
1849 @item @option{tramp-wrong-passwd-regexp}
1850 @vindex tramp-password-prompt-regexp
1851 @vindex tramp-wrong-passwd-regexp
1853 @value{tramp} uses @option{tramp-password-prompt-regexp} to
1854 distinguish between prompts for passwords and prompts for passphrases.
1855 By default, @option{tramp-password-prompt-regexp} handles the
1856 detection in English language environments. See a localization
1861 (custom-set-variables
1862 '(tramp-password-prompt-regexp
1866 '("passphrase" "Passphrase"
1868 "password" "Password"
1870 "passwort" "Passwort"
1872 "mot de passe" "Mot de passe")
1879 Similar localization may be necessary for handling wrong password
1880 prompts, for which @value{tramp} uses @option{tramp-wrong-passwd-regexp}.
1882 @item @command{tset} and other questions
1883 @cindex unix command tset
1884 @cindex tset unix command
1885 @vindex tramp-terminal-type
1887 To suppress inappropriate prompts for terminal type, @value{tramp}
1888 sets the @env{TERM} to @code{dumb} before the remote login process
1889 begins via the user option @option{tramp-terminal-type}. This will
1890 silence common @command{tset} related prompts.
1892 @value{tramp}'s strategy for handling such prompts (commonly triggered
1893 from login scripts on remote hosts) is to set the environment
1894 variables so that no prompts interrupt the shell initialization
1897 @vindex tramp-actions-before-shell
1898 An alternative approach is to configure @value{tramp} with strings
1899 that can identify such questions using
1900 @code{tramp-actions-before-shell}. Example:
1904 (defconst my-tramp-prompt-regexp
1905 (concat (regexp-opt '("Enter the birth date of your mother:") t)
1907 "Regular expression matching my login prompt question.")
1911 (defun my-tramp-action (proc vec)
1912 "Enter \"19000101\" in order to give a correct answer."
1913 (save-window-excursion
1914 (with-current-buffer (tramp-get-connection-buffer vec)
1915 (tramp-message vec 6 "\n%s" (buffer-string))
1916 (tramp-send-string vec "19000101"))))
1920 (add-to-list 'tramp-actions-before-shell
1921 '(my-tramp-prompt-regexp my-tramp-action))
1926 @item Conflicting names for users and variables in @file{.profile}
1928 When a user name is the same as a variable name in a local file, such
1929 as @file{.profile}, then @value{tramp} may send incorrect values for
1930 environment variables. To avoid incorrect values, change the local
1931 variable name to something different from the user name. For example,
1932 if the user name is @env{FRUMPLE}, then change the variable name to
1936 @item Non-Bourne commands in @file{.profile}
1938 When the remote host's @file{.profile} is also used for shells other
1939 than Bourne shell, then some incompatible syntaxes for commands in
1940 @file{.profile} may trigger errors in Bourne shell on the host and may
1941 not complete client's @value{tramp} connections.
1943 One example of a Bourne shell incompatible syntax in @file{.profile}:
1944 using @command{export FOO=bar} instead of @command{FOO=bar; export
1945 FOO}. After remote login, @value{tramp} will trigger an error during
1946 its execution of @command{/bin/sh} on the remote host because Bourne
1947 shell does not recognize the export command as entered in
1950 Likewise, (@code{~}) character in paths will cause errors because
1951 Bourne shell does not do (@code{~}) character expansions.
1953 One approach to avoiding these incompatibilities is to make all
1954 commands in @file{~/.shrc} and @file{~/.profile} Bourne shell
1955 compatible so @value{tramp} can complete connections to that remote.
1956 To accommodate using non-Bourne shells on that remote, use other
1957 shell-specific config files. For example, bash can use
1958 @file{~/.bash_profile} and ignore @file{.profile}.
1961 @item Interactive shell prompt
1963 @value{tramp} redefines the remote shell prompt internally for robust
1964 parsing. This redefinition affects the looks of a prompt in an
1965 interactive remote shell through commands, such as @kbd{M-x
1966 shell}. Such prompts, however, can be reset to something more readable
1967 and recognizable using these @value{tramp} variables.
1969 @value{tramp} sets the @env{INSIDE_EMACS} variable in the startup
1970 script file @file{~/.emacs_SHELLNAME}.
1972 @env{SHELLNAME} is @code{bash} or equivalent shell names. Change it by
1973 setting the environment variable @env{ESHELL} in the @file{.emacs} as
1977 (setenv "ESHELL" "bash")
1980 Then re-set the prompt string in @file{~/.emacs_SHELLNAME} as follows:
1984 # Reset the prompt for remote @value{tramp} shells.
1985 if [ "$@{INSIDE_EMACS/*tramp*/tramp@}" == "tramp" ] ; then
1992 @xref{Interactive Shell, , , emacs}.
1995 @item @command{busybox} / @command{nc}
1996 @cindex unix command nc
1997 @cindex nc unix command
1999 @value{tramp}'s @option{nc} method uses the @command{nc} command to
2000 install and execute a listener as follows (see @code{tramp-methods}):
2006 The above command-line syntax has changed with @command{busybox}
2007 versions. If @command{nc} refuses the @samp{-p} parameter, then
2008 overwrite as follows:
2013 'tramp-connection-properties
2014 `(,(regexp-quote "192.168.0.1")
2015 "remote-copy-args" (("-l") ("%r"))))
2020 where @samp{192.168.0.1} is the remote host IP address
2021 (@pxref{Predefined connection information}).
2026 @node Android shell setup
2027 @section Android shell setup hints
2028 @cindex android shell setup for ssh
2030 @value{tramp} uses the @option{adb} method to access Android devices.
2031 Android devices provide a restricted shell access through an USB
2032 connection. The local host must have the @command{adb} program
2033 installed. Usually, it is sufficient to open the file
2034 @file{@trampfn{adb,,/}}. Then you can navigate in the filesystem via
2037 Alternatively, applications such as @code{SSHDroid} that run
2038 @command{sshd} process on the Android device can accept any
2039 @option{ssh}-based methods provided these settings are adjusted:
2043 @command{sh} must be specified for remote shell since Android devices
2044 do not provide @command{/bin/sh}. @command{sh} will then invoke
2045 whatever shell is installed on the device with this setting:
2049 (add-to-list 'tramp-connection-properties
2050 (list (regexp-quote "192.168.0.26") "remote-shell" "sh"))
2055 where @samp{192.168.0.26} is the Android device's IP address.
2056 (@pxref{Predefined connection information}).
2059 @value{tramp} requires preserving @env{PATH} environment variable from
2060 user settings. Android devices prefer @file{/system/xbin} path over
2061 @file{/system/bin}. Both of these are set as follows:
2065 (add-to-list 'tramp-remote-path 'tramp-own-remote-path)
2066 (add-to-list 'tramp-remote-path "/system/xbin")
2071 When the Android device is not @samp{rooted}, specify a writable
2072 directory for temporary files:
2075 (add-to-list 'tramp-remote-process-environment "TMPDIR=$HOME")
2079 Open a remote connection with the command @kbd{C-x C-f
2080 @trampfn{ssh,192.168.0.26#2222,}}, where @command{sshd} is listening
2081 on port @samp{2222}.
2083 To add a corresponding entry to the @file{~/.ssh/config} file
2084 (recommended), use this:
2089 HostName 192.168.0.26
2096 To use the host name @samp{android} instead of the IP address shown in
2097 the previous example, fix the connection properties as follows:
2101 (add-to-list 'tramp-connection-properties
2102 (list (regexp-quote "android") "remote-shell" "sh"))
2107 Open a remote connection with a more concise command @kbd{C-x C-f
2108 @trampfn{ssh,android,}}.
2112 @node Auto-save and Backup
2113 @section Auto-save and Backup configuration
2116 @vindex backup-directory-alist
2118 To avoid @value{tramp} from saving backup files owned by @samp{root}
2119 to locations accessible to others, default backup settings in
2120 @option{backup-directory-alist} have to be altered.
2122 Here's a scenario where files could be inadvertently exposed. Emacs
2123 by default writes backup files to the same directory as the original
2124 files unless changed to another location, such as
2125 @file{~/.emacs.d/backups/}. Such a directory will also be used by
2126 default by @value{tramp} when using, say, a restricted file
2127 @file{@trampfn{su,root@@localhost,/etc/secretfile}}. The backup file
2128 of the secretfile is now owned by the user logged in from
2129 @value{tramp} and not @samp{root}.
2131 When @option{backup-directory-alist} is @code{nil} (the default), such
2132 problems do not occur.
2134 To ``turn off'' the backup feature for @value{tramp} files and stop
2135 @value{tramp} from saving to the backup directory, use this:
2139 (add-to-list 'backup-directory-alist
2140 (cons tramp-file-name-regexp nil))
2145 Disabling backups can be targeted to just the @option{su} and
2146 @option{sudo} methods:
2150 (setq backup-enable-predicate
2152 (and (normal-backup-enable-predicate name)
2154 (let ((method (file-remote-p name 'method)))
2155 (when (stringp method)
2156 (member method '("su" "sudo"))))))))
2160 Another option is to create better backup file naming with user and
2161 host names prefixed to the file name. For example, transforming
2162 @file{/etc/secretfile} to
2163 @file{~/.emacs.d/backups/!su:root@@localhost:!etc!secretfile}, set the
2164 @value{tramp} user option @option{tramp-backup-directory-alist} from
2165 the existing user option @option{backup-directory-alist}.
2167 Then @value{tramp} backs up to a file name that is transformed with a
2168 prefix consisting of the DIRECTORY name. This file name prefixing
2169 happens only when the DIRECTORY is an absolute local file name.
2176 (add-to-list 'backup-directory-alist
2177 (cons "." "~/.emacs.d/backups/"))
2178 (custom-set-variables
2179 '(tramp-backup-directory-alist backup-directory-alist 6 nil (tramp)))
2184 The backup file name of
2185 @file{@trampfn{su,root@@localhost,/etc/secretfile}} would be
2187 @file{@trampfn{su,root@@localhost,~/.emacs.d/backups/!su:root@@localhost:!etc!secretfile~}}
2190 @file{@trampfn{su,root@@localhost,~/.emacs.d/backups/![su!root@@localhost]!etc!secretfile~}}
2193 Just as for backup files, similar issues of file naming affect
2194 auto-saving @value{tramp} files. Auto-saved files are saved in the
2195 directory specified by the user option
2196 @option{auto-save-file-name-transforms}. By default this is set to
2197 the local temporary directory. But in some versions of Debian
2198 GNU/Linux, this points to the source directory where the Emacs was
2199 compiled. Reset such values to a valid directory.
2201 Set @option{auto-save-file-name-transforms} to @code{nil} to save
2202 auto-saved files to the same directory as the original file.
2204 Alternatively, set the user option @option{tramp-auto-save-directory}
2205 to direct all auto saves to that location.
2207 @node Windows setup hints
2208 @section Issues with Cygwin ssh
2209 @cindex cygwin, issues
2211 This section is incomplete. Please share your solutions.
2213 @cindex method sshx with cygwin
2214 @cindex sshx method with cygwin
2216 Cygwin's @command{ssh} works only with a Cygwin version of Emacs. To
2217 check for compatibility: type @kbd{M-x eshell}, and start @kbd{ssh
2218 test.host}. Incompatibilities trigger this message:
2221 Pseudo-terminal will not be allocated because stdin is not a terminal.
2224 Some older versions of Cygwin's @command{ssh} work with the
2225 @option{sshx} access method. Consult Cygwin's FAQ at
2226 @uref{https://cygwin.com/faq/} for details.
2228 @cindex cygwin and fakecygpty
2229 @cindex fakecygpty and cygwin
2231 On @uref{https://www.emacswiki.org/emacs/SshWithNTEmacs, the Emacs
2232 Wiki} it is explained how to use the helper program @code{fakecygpty}
2233 to fix this problem.
2235 @cindex method scpx with cygwin
2236 @cindex scpx method with cygwin
2238 When using the @option{scpx} access method, Emacs may call
2239 @command{scp} with MS Windows file naming, such as @code{c:/foo}. But
2240 the version of @command{scp} that is installed with Cygwin does not
2241 know about MS Windows file naming, which causes it to incorrectly look
2242 for a host named @code{c}.
2244 A workaround: write a wrapper script for @option{scp} to convert
2245 Windows file names to Cygwin file names.
2247 @cindex cygwin and ssh-agent
2248 @cindex SSH_AUTH_SOCK and emacs on ms windows
2250 When using the @command{ssh-agent} on MS Windows for password-less
2251 interaction, @option{ssh} methods depend on the environment variable
2252 @env{SSH_AUTH_SOCK}. But this variable is not set when Emacs is
2253 started from a Desktop shortcut and authentication fails.
2255 One workaround is to use an MS Windows based SSH Agent, such as
2256 Pageant. It is part of the Putty Suite of tools.
2258 The fallback is to start Emacs from a shell.
2262 @chapter Using @value{tramp}
2263 @cindex using @value{tramp}
2265 @value{tramp} operates transparently, accessing remote files as if
2266 they are local. However, @value{tramp} employs a formalized remote
2267 file naming syntax to perform its functions transparently. This
2268 syntax consists of many parts specifying access methods,
2269 authentication, host names, and file names. Ange FTP uses a similar
2274 Unlike opening local files in Emacs, which are instantaneous, opening
2275 remote files in @value{tramp} is slower at first. Sometimes there is
2276 a noticeable delay before the prompts for passwords or authentication
2277 appear in the minibuffer. Hitting @kbd{@key{RET}} or other keys
2278 during this gap will be processed by Emacs. This type-ahead facility
2279 is a feature of Emacs that may cause missed prompts when using
2283 * File name syntax:: @value{tramp} file name conventions.
2285 * Change file name syntax:: Alternative file name syntax.
2287 * File name completion:: File name completion.
2288 * Ad-hoc multi-hops:: Declaring multiple hops in the file name.
2289 * Remote processes:: Integration with other Emacs packages.
2290 * Cleanup remote connections:: Cleanup remote connections.
2294 @node File name syntax
2295 @section @value{tramp} file name conventions
2296 @cindex file name syntax
2297 @cindex file name examples
2299 @file{@trampfn{method,host,/path/to/file}} opens file @var{/path/to/file}
2300 on the remote host @var{host}, using the method @var{method}.
2303 @item @value{prefix}ssh@value{postfixhop}melancholia@value{postfix}.emacs
2304 For the file @file{.emacs} located in the home directory, on the host
2305 @code{melancholia}, using method @code{ssh}.
2307 @item @value{prefix}ssh@value{postfixhop}melancholia.danann.net@value{postfix}.emacs
2308 For the file @file{.emacs} specified using the fully qualified domain name of
2311 @item @value{prefix}ssh@value{postfixhop}melancholia@value{postfix}~/.emacs
2312 For the file @file{.emacs} specified using the @file{~}, which is expanded.
2314 @item @value{prefix}ssh@value{postfixhop}melancholia@value{postfix}~daniel/.emacs
2315 For the file @file{.emacs} located in @code{daniel}'s home directory
2316 on the host, @code{melancholia}. The @file{~<user>} construct is
2317 expanded to the home directory of that user on the remote host.
2319 @item @value{prefix}ssh@value{postfixhop}melancholia@value{postfix}/etc/squid.conf
2320 For the file @file{/etc/squid.conf} on the host @code{melancholia}.
2324 @var{host} can take IPv4 or IPv6 address, as in
2325 @file{@trampfn{ssh,127.0.0.1,.emacs}} or
2326 @file{@trampfn{ssh,@value{ipv6prefix}::1@value{ipv6postfix},.emacs}}.
2328 For syntactical reasons, IPv6 addresses must be embedded in square
2329 brackets @file{@value{ipv6prefix}} and @file{@value{ipv6postfix}}.
2332 By default, @value{tramp} will use the current local user name as the
2333 remote user name for log in to the remote host. Specifying a different
2334 name using the proper syntax will override this default behavior:
2337 @trampfn{method,user@@host,path/to/file}
2340 @file{@trampfn{ssh,daniel@@melancholia,.emacs}} is for file
2341 @file{.emacs} in @code{daniel}'s home directory on the host,
2342 @code{melancholia}, accessing via method @code{ssh}.
2344 For specifying port numbers, affix @file{#<port>} to the host
2345 name. For example: @file{@trampfn{ssh,daniel@@melancholia#42,.emacs}}.
2347 All method, user name, host name, port number and local name parts are
2348 optional, @xref{Default Method}, @xref{Default User}, @xref{Default Host}.
2350 For syntactical reasons, the default method must be indicated by the
2351 pseudo method @file{-}.
2356 @node Change file name syntax
2357 @section Alternative file name syntax
2358 @cindex change file name syntax
2359 @cindex alternative file name syntax
2361 The syntax described in @ref{File name syntax} is the @code{default}
2362 syntax, which is active after Emacs startup. However, this can be
2365 @deffn Command tramp-change-syntax syntax
2366 This command changes the syntax @value{tramp} uses for remote file
2367 names. Beside the @code{default} value, @var{syntax} can be
2370 @item @code{simplified}
2371 @cindex simplified syntax
2373 The remote file name syntax is similar to the syntax used by Ange FTP.
2374 A remote file name has the form
2375 @code{@value{prefix}user@@host@value{postfix}path/to/file}. The
2376 @code{user@@} part is optional, and the method is determined by
2377 @ref{Default Method}.
2379 @item @code{separate}
2380 @cindex separate syntax
2384 @include trampver.texi
2385 The remote file name syntax is similar to the syntax used by XEmacs.
2386 A remote file name has the form
2387 @code{@trampfn{method,user@@host,path/to/file}}. The @code{method}
2388 and @code{user@@} parts are optional.
2391 @include trampver.texi
2395 @defvar tramp-file-name-regexp
2396 This variable keeps a regexp which matches the selected remote file
2397 name syntax. However, it is not recommended to use this variable in
2398 external packages, a call of @code{file-remote-p} is much more
2401 @pxref{Magic File Names, , , elisp}
2407 @node File name completion
2408 @section File name completion
2409 @cindex file name completion
2411 @value{tramp} can complete the following @value{tramp} file name
2412 components: method names, user names, host names, and file names
2413 located on remote hosts. Enable this by activating partial completion
2416 @xref{Completion Options, , , emacs}.
2419 For example, type @kbd{C-x C-f @value{prefixwithspace} s @key{TAB}},
2420 @value{tramp} completion choices show up as
2424 @multitable @columnfractions .2 .2 .2 .2 .2
2427 @value{prefixhop}scp@value{postfix} @tab @c
2428 @value{prefixhop}scpx@value{postfix} @tab @c
2429 @value{prefixhop}sftp@value{postfix} @tab @c
2430 @value{prefixhop}sg@value{postfix}
2432 @value{prefixhop}smb@value{postfix} @tab @c
2434 @value{prefixhop}ssh@value{postfix} @tab @c
2435 @value{prefixhop}sshx@value{postfix} @tab @c
2436 @value{prefixhop}su@value{postfix}
2438 @value{prefixhop}sudo@value{postfix} @tab @c
2444 @samp{@value{prefixhop}ssh@value{postfixhop}} is a possible
2445 completion for the respective method, and @samp{sbin/} stands for the
2446 directory @file{/sbin} on your local host.
2448 Type @kbd{s h @value{postfixhop}} for the minibuffer completion to
2449 @samp{@value{prefix}ssh@value{postfixhop}}. Typing @kbd{@key{TAB}}
2450 shows host names @value{tramp} extracts from @file{~/.ssh/config}
2455 @multitable @columnfractions .5 .5
2457 @value{prefixhop}ssh@value{postfixhop}127.0.0.1@value{postfix} @tab @c
2458 @value{prefixhop}ssh@value{postfixhop}192.168.0.1@value{postfix}
2460 @value{prefixhop}ssh@value{postfixhop}@value{ipv6prefix}::1@value{ipv6postfix}@value{postfix} @tab @c
2461 @value{prefixhop}ssh@value{postfixhop}localhost@value{postfix}
2463 @value{prefixhop}ssh@value{postfixhop}melancholia.danann.net@value{postfix} @tab @c
2464 @value{prefixhop}ssh@value{postfixhop}melancholia@value{postfix}
2469 Choose a host from the above list and then continue to complete file
2472 When the configuration (@pxref{Customizing Completion}) includes user
2473 names, then the completion lists will account for the user names as well.
2475 Remote hosts previously visited or hosts whose connections are kept
2476 persistently (@pxref{Connection caching}) will be included in the
2479 After remote host name completion comes completion of file names on
2480 the remote host. It works the same as with local host file completion
2481 except that killing with double-slash @file{//} kills only the file
2482 name part of the @value{tramp} file name syntax. A triple-slash
2483 stands for the default behavior.
2485 @xref{Minibuffer File, , , emacs}.
2493 @kbd{C-x C-f @trampfn{ssh,melancholia,/usr/local/bin//etc} @key{TAB}}
2494 @print{} @trampfn{ssh,melancholia,/etc}
2496 @kbd{C-x C-f @trampfn{ssh,melancholia,//etc} @key{TAB}}
2499 @kbd{C-x C-f @trampfn{ssh,melancholia,/usr/local/bin///etc} @key{TAB}}
2504 During file name completion, remote directory contents are re-read
2505 regularly to account for any changes in the filesystem that may affect
2506 the completion candidates. Such re-reads can account for changes to
2507 the file system by applications outside Emacs (@pxref{Connection
2510 @defopt tramp-completion-reread-directory-timeout
2511 The timeout is number of seconds since last remote command for
2512 rereading remote directory contents. A value of 0 re-reads
2513 immediately during file name completion, @code{nil} uses cached
2518 @node Ad-hoc multi-hops
2519 @section Declaring multiple hops in the file name
2520 @cindex multi-hop, ad-hoc
2521 @cindex proxy hosts, ad-hoc
2523 @value{tramp} file name syntax can accommodate ad hoc specification of
2524 multiple proxies without using @option{tramp-default-proxies-alist}
2525 configuration setup(@pxref{Multi-hops}).
2527 Each proxy is specified using the same syntax as the remote host
2528 specification minus the file name part. Each hop is separated by a
2529 @samp{|}. Chain the proxies from the starting host to the destination
2530 remote host name and file name. For example, hopping over a single
2531 proxy @samp{bird@@bastion} to a remote file on @samp{you@@remotehost}:
2534 @c @kbd{C-x C-f @trampfn{ssh@value{postfixhop}bird@@bastion|ssh,you,remotehost,/path}}
2535 @kbd{C-x C-f @value{prefix}ssh@value{postfixhop}bird@@bastion|ssh@value{postfixhop}you@@remotehost@value{postfix}/path}
2538 Proxies can take patterns @code{%h} or @code{%u}.
2540 @value{tramp} adds the ad-hoc definitions on the fly to
2541 @option{tramp-default-proxies-alist} and is available for re-use
2542 during that Emacs session. Subsequent @value{tramp} connections to
2543 the same remote host can then use the shortcut form:
2544 @samp{@trampfn{ssh,you@@remotehost,/path}}.
2546 @defopt tramp-save-ad-hoc-proxies
2547 For ad-hoc definitions to be saved automatically in
2548 @option{tramp-default-proxies-alist} for future Emacs sessions, set
2549 @option{tramp-save-ad-hoc-proxies} to non-@code{nil}.
2552 (custom-set-variables '(tramp-save-ad-hoc-proxies t nil (tramp)))
2557 @node Remote processes
2558 @section Integration with other Emacs packages
2562 @value{tramp} supports starting new running processes on the remote
2563 host for discovering remote file names. Emacs packages on the remote
2564 host need no specific modifications for @value{tramp}'s use.
2566 This type of integration does not work with the @option{ftp} method,
2567 and does not support the pty association as specified in
2568 @code{start-file-process}.
2570 @code{process-file} and @code{start-file-process} work on the remote
2571 host when the variable @code{default-directory} is remote:
2575 (let ((default-directory "/ssh:remote.host:"))
2576 (start-file-process "grep" (get-buffer-create "*grep*")
2577 "/bin/sh" "-c" "grep -e tramp *"))
2581 Remote processes do not apply to GVFS (see @ref{GVFS based methods})
2582 because the remote file system is mounted on the local host and
2583 @value{tramp} just accesses by changing the @code{default-directory}.
2585 @value{tramp} starts a remote process when a command is executed in a
2586 remote file or directory buffer. As of now, these packages have been
2587 integrated to work with @value{tramp}: @file{compile.el} (commands
2588 like @code{compile} and @code{grep}) and @file{gud.el} (@code{gdb} or
2591 For @value{tramp} to find the command on the remote, it must be
2592 accessible through the default search path as setup by @value{tramp}
2593 upon first connection. Alternatively, use an absolute path or extend
2594 @option{tramp-remote-path} (see @ref{Remote programs}):
2598 (add-to-list 'tramp-remote-path "~/bin")
2599 (add-to-list 'tramp-remote-path "/appli/pub/bin")
2603 Customize user option @option{tramp-remote-process-environment} to
2604 suit the remote program's environment for the remote host.
2605 @option{tramp-remote-process-environment} is a list of strings
2606 structured similar to @code{process-environment}, where each element
2607 is a string of the form @samp{ENVVARNAME=VALUE}.
2609 To avoid any conflicts with local host environment variables set
2610 through local configuration files, such as @file{~/.profile}, use
2611 @samp{ENVVARNAME=} to unset them for the remote environment.
2614 Use @code{add-to-list} to add entries:
2617 (add-to-list 'tramp-remote-process-environment "JAVA_HOME=/opt/java")
2620 Modifying or deleting already existing values in the
2621 @option{tramp-remote-process-environment} list may not be feasible on
2622 restricted remote hosts. For example, some system administrators
2623 disallow changing @env{HISTORY} environment variable. To accommodate
2624 such restrictions when using @value{tramp}, fix the
2625 @option{tramp-remote-process-environment} by the following code in the
2626 local @file{.emacs} file:
2630 (let ((process-environment tramp-remote-process-environment))
2631 (setenv "HISTORY" nil)
2632 (setq tramp-remote-process-environment process-environment))
2636 Setting the @env{ENV} environment variable instructs some shells to
2637 read an initialization file. Per default, @value{tramp} has disabled
2638 this. You could overwrite this behavior by evaluating
2642 (let ((process-environment tramp-remote-process-environment))
2643 (setenv "ENV" "$HOME/.profile")
2644 (setq tramp-remote-process-environment process-environment))
2648 @value{tramp} does not use the defaults specified in
2649 @code{process-environment} for running @code{process-file} or
2650 @code{start-file-process} on remote hosts. When values from
2651 @code{process-environment} are needed for remote processes, then set
2656 (let ((process-environment (cons "HGPLAIN=1" process-environment)))
2657 (process-file @dots{}))
2661 This works only for environment variables not already set in the
2662 @code{process-environment}.
2664 For integrating other Emacs packages so @value{tramp} can execute
2665 remotely, please file a bug report. @xref{Bug Reports}.
2668 @subsection Running remote programs that create local X11 windows
2670 To allow a remote program to create an X11 window on the local host,
2671 set the @env{DISPLAY} environment variable for the remote host as
2672 follows in the local @file{.emacs} file:
2676 (add-to-list 'tramp-remote-process-environment
2677 (format "DISPLAY=%s" (getenv "DISPLAY")))
2682 @code{(getenv "DISPLAY")} should return a recognizable name for the
2683 local host that the remote host can redirect X11 window
2684 interactions. If querying for a recognizable name is not possible for
2685 whatever reason, then replace @code{(getenv "DISPLAY")} with a
2686 hard-coded, fixed name. Note that using @code{:0} for X11 display name
2687 here will not work as expected.
2689 An alternate approach is specify @code{ForwardX11 yes} or
2690 @code{ForwardX11Trusted yes} in the file @file{~/.ssh/config} on the
2694 @subsection Running @code{shell} on a remote host
2697 Set @option{explicit-shell-file-name} to the appropriate shell name
2698 when using @value{tramp} between two hosts with different operating
2699 systems, such as @samp{windows-nt} and @samp{gnu/linux}. This option
2700 ensures the correct name of the remote shell program.
2702 When @option{explicit-shell-file-name} is equal to @code{nil}, calling
2703 @code{shell} interactively will prompt for a shell name.
2705 Starting with Emacs 26, you could use connection-local variables for
2706 setting different values of @option{explicit-shell-file-name} for
2707 different remote hosts.
2709 @pxref{Connection Local Variables, , , elisp}
2714 (connection-local-set-profile-variables
2716 '((explicit-shell-file-name . "/bin/bash")
2717 (explicit-bash-args . ("-i"))))
2721 (connection-local-set-profile-variables
2723 '((explicit-shell-file-name . "/bin/ksh")
2724 (explicit-ksh-args . ("-i"))))
2728 (connection-local-set-profiles
2729 '(:application tramp :protocol "ssh" :machine "localhost")
2734 (connection-local-set-profiles
2735 `(:application tramp :protocol "sudo"
2736 :user "root" :machine ,(system-name))
2742 @subsection Running @code{shell-command} on a remote host
2743 @cindex shell-command
2745 @code{shell-command} executes commands synchronously or asynchronously
2746 on remote hosts and displays output in buffers on the local
2751 @kbd{C-x C-f @trampfn{sudo,,} @key{RET}}
2752 @kbd{M-! tail -f /var/log/syslog.log & @key{RET}}
2756 @command{tail} command outputs continuously to the local buffer,
2757 @file{*Async Shell Command*}
2759 @kbd{M-x auto-revert-tail-mode} runs similarly showing continuous output.
2762 @subsection Running @code{eshell} on a remote host
2765 @value{tramp} is integrated into @file{eshell.el}, which enables
2766 interactive eshell sessions on remote hosts at the command prompt.
2767 You must add the module @code{em-tramp} to @code{eshell-modules-list}.
2768 Here's a sample interaction after opening @kbd{M-x eshell} on a remote
2773 @b{~ $} cd @trampfn{sudo,,/etc} @key{RET}
2774 @b{@trampfn{sudo,root@@host,/etc} $} hostname @key{RET}
2776 @b{@trampfn{sudo,root@@host,/etc} $} id @key{RET}
2777 uid=0(root) gid=0(root) groups=0(root)
2778 @b{@trampfn{sudo,root@@host,/etc} $} find-file shadow @key{RET}
2780 @b{@trampfn{sudo,root@@host,/etc} $}
2784 @code{eshell} added custom @code{su} and @code{sudo} commands that set
2785 the default directory correctly for the @file{*eshell*} buffer.
2786 @value{tramp} silently updates @option{tramp-default-proxies-alist}
2787 with an entry for this directory (@pxref{Multi-hops}):
2791 @b{~ $} cd @trampfn{ssh,user@@remotehost,/etc} @key{RET}
2792 @b{@trampfn{ssh,user@@remotehost,/etc} $} find-file shadow @key{RET}
2793 File is not readable: @trampfn{ssh,user@@remotehost,/etc/shadow}
2794 @b{@trampfn{ssh,user@@remotehost,/etc} $} sudo find-file shadow @key{RET}
2799 @b{@trampfn{ssh,user@@remotehost,/etc} $} su - @key{RET}
2800 @b{@trampfn{su,root@@remotehost,/root} $} id @key{RET}
2801 uid=0(root) gid=0(root) groups=0(root)
2802 @b{@trampfn{su,root@@remotehost,/root} $}
2807 @anchor{Running a debugger on a remote host}
2808 @subsection Running a debugger on a remote host
2813 @file{gud.el} provides a unified interface to symbolic debuggers
2815 (@ref{Debuggers, , , emacs}).
2817 @value{tramp} can run debug on remote hosts by calling @code{gdb}
2818 with a remote file name:
2822 @kbd{M-x gdb @key{RET}}
2823 @b{Run gdb (like this):} gdb -i=mi @trampfn{ssh,host,~/myprog} @key{RET}
2827 Since the remote @code{gdb} and @code{gdb-inferior} processes do not
2828 belong to the same process group on the remote host, there will be a
2829 warning, which can be ignored:
2832 &"warning: GDB: Failed to set controlling terminal: Operation not permitted\n"
2835 Relative file names are based on the remote default directory. When
2836 @file{myprog.pl} exists in @file{@trampfn{ssh,host,/home/user}}, valid
2841 @kbd{M-x perldb @key{RET}}
2842 @b{Run perldb (like this):} perl -d myprog.pl @key{RET}
2846 Just the local part of a remote file name, such as @kbd{perl -d
2847 /home/user/myprog.pl}, is not possible.
2849 Arguments of the program to be debugged must be literal, can take
2850 relative or absolute paths, but not remote paths.
2853 @subsection Running remote processes on MS Windows hosts
2857 @command{winexe} runs processes on a remote MS Windows host, and
2858 @value{tramp} can use it for @code{process-file} and
2859 @code{start-file-process}.
2861 @code{tramp-smb-winexe-program} specifies the local @command{winexe}
2862 command. Powershell V2.0 on the remote host is required to run
2863 processes triggered from @value{tramp}.
2865 @option{explicit-shell-file-name} and @option{explicit-*-args} have to
2866 be set properly so @kbd{M-x shell} can open a proper remote shell on a
2867 MS Windows host. To open @command{cmd}, set it as follows:
2871 (setq explicit-shell-file-name "cmd"
2872 explicit-cmd-args '("/q"))
2877 To open @command{powershell} as a remote shell, use this:
2881 (setq explicit-shell-file-name "powershell"
2882 explicit-powershell-args '("-file" "-"))
2887 @node Cleanup remote connections
2888 @section Cleanup remote connections
2891 @value{tramp} provides several ways to flush remote connections.
2893 @deffn Command tramp-cleanup-connection vec
2894 This command flushes all connection related objects. @option{vec} is
2895 the internal representation of a remote connection. When called
2896 interactively, this command lists active remote connections in the
2897 minibuffer. Each connection is of the format
2898 @file{@trampfn{method,user@@host,}}. Flushing remote connections also
2899 cleans the password cache (@pxref{Password handling}), file cache,
2900 connection cache (@pxref{Connection caching}), and connection buffers.
2903 @deffn Command tramp-cleanup-this-connection
2904 Flushes only the current buffer's remote connection objects, the same
2905 as in @code{tramp-cleanup-connection}.
2908 @deffn Command tramp-cleanup-all-connections
2909 Flushes all active remote connection objects, the same as in
2910 @code{tramp-cleanup-connection}.
2913 @deffn Command tramp-cleanup-all-buffers
2914 Just as for @code{tramp-cleanup-all-connections}, all remote
2915 connections are cleaned up in addition to killing buffers related to
2916 that remote connection.
2921 @chapter Reporting Bugs and Problems
2924 @value{tramp}'s development team is actively engaged in solving bugs
2925 and problems and looks to feature requests and suggestions.
2927 @value{tramp}'s mailing list is the place for more advice and
2928 information on working with @value{tramp}, solving problems,
2929 discussing, and general discussions about @value{tramp}.
2931 @value{tramp}'s mailing list is moderated but even non-subscribers can
2932 post for moderator approval. Sometimes this approval step may take as
2933 long as 48 hours due to public holidays.
2935 @email{tramp-devel@@gnu.org} is the mailing list. Messages sent to
2936 this address go to all the subscribers. This is @emph{not} the
2937 address to send subscription requests to.
2939 To subscribe to the mailing list, visit:
2940 @uref{https://lists.gnu.org/mailman/listinfo/tramp-devel/, the
2941 @value{tramp} Mail Subscription Page}.
2943 @ifset installchapter
2944 Before sending a bug report, run the test suite first @ref{Testing}.
2948 Check if the bug or problem is already addressed in @xref{Frequently
2951 Run @kbd{M-x tramp-bug} to generate a buffer with details of the
2952 system along with the details of the @value{tramp}
2953 installation. Please include these details with the bug report.
2955 The bug report must describe in as excruciating detail as possible the
2956 steps required to reproduce the problem. These details must include
2957 the setup of the remote host and any special or unique conditions that
2960 Include a minimal test case that reproduces the problem. This will
2961 help the development team find the best solution and avoid unrelated
2964 To exclude cache-related problems, flush all caches before running the
2965 test, @ref{Cleanup remote connections}.
2967 When including @value{tramp}'s messages in the bug report, increase
2968 the verbosity level to 6 (@pxref{Traces and Profiles, Traces}) in the
2969 @file{~/.emacs} file before repeating steps to the bug. Include the
2970 contents of the @file{*tramp/foo*} and @file{*debug tramp/foo*}
2971 buffers with the bug report.
2973 @strong{Note} that a verbosity level greater than 6 is not necessary
2974 at this stage. Also note that a verbosity level of 6 or greater, the
2975 contents of files and directories will be included in the debug
2976 buffer. Passwords typed in @value{tramp} will never be included
2980 @node Frequently Asked Questions
2981 @chapter Frequently Asked Questions
2982 @cindex frequently asked questions
2987 Where is the latest @value{tramp}?
2989 @value{tramp} is available at the GNU URL:
2992 @uref{https://ftp.gnu.org/gnu/tramp/}
2995 @value{tramp}'s GNU project page is located here:
2998 @uref{https://savannah.gnu.org/projects/tramp/}
3002 Which systems does it work on?
3004 The package works successfully on Emacs 24, Emacs 25, and Emacs 26.
3006 While Unix and Unix-like systems are the primary remote targets,
3007 @value{tramp} has equal success connecting to other platforms, such as
3012 How to speed up @value{tramp}?
3014 @value{tramp} does many things in the background, some of which
3015 depends on network speeds, response speeds of remote hosts, and
3016 authentication delays. During these operations, @value{tramp}'s
3017 responsiveness slows down. Some suggestions within the scope of
3018 @value{tramp}'s settings include:
3020 Use an external method, such as @option{scp}, which are faster than
3023 Keep the file @option{tramp-persistency-file-name}, which is where
3024 @value{tramp} caches remote information about hosts and files. Caching
3025 is enabled by default. Don't disable it.
3027 Set @code{remote-file-name-inhibit-cache} to @code{nil} if remote
3028 files are not independently updated outside @value{tramp}'s control.
3029 That cache cleanup will be necessary if the remote directories or
3030 files are updated independent of @value{tramp}.
3032 Set @option{tramp-completion-reread-directory-timeout} to @code{nil} to
3033 speed up completions, @ref{File name completion}.
3035 Disable version control to avoid delays:
3039 (setq vc-ignore-dir-regexp
3040 (format "\\(%s\\)\\|\\(%s\\)"
3041 vc-ignore-dir-regexp
3042 tramp-file-name-regexp))
3046 If this is too radical, because you want to use version control
3047 remotely, trim @code{vc-handled-backends} to just those you care
3051 (setq vc-handled-backends '(SVN Git))
3054 Disable excessive traces. Set @code{tramp-verbose} to 3 or lower,
3055 default being 3. Increase trace levels temporarily when hunting for
3059 @value{tramp} does not connect to the remote host
3061 Three main reasons for why @value{tramp} does not connect to the remote host:
3065 Unknown characters in the prompt
3067 @value{tramp} needs a clean recognizable prompt on the remote host for
3068 accurate parsing. Shell prompts that contain escape sequences for
3069 coloring cause parsing problems. @ref{Remote shell setup} for
3070 customizing prompt detection using regular expressions.
3072 To check if the remote host's prompt is being recognized, use this
3073 test: switch to @value{tramp} connection buffer @file{*tramp/foo*},
3074 put the cursor at the top of the buffer, and then apply the following
3078 @kbd{M-: (re-search-forward (concat tramp-shell-prompt-pattern "$"))}
3081 If the cursor has not moved to the prompt at the bottom of the buffer,
3082 then @value{tramp} has failed to recognize the prompt.
3084 When using zsh on remote hosts, disable zsh line editor because zsh
3085 uses left-hand side and right-hand side prompts in parallel. Add the
3086 following line to @file{~/.zshrc}:
3089 [ $TERM = "dumb" ] && unsetopt zle && PS1='$ '
3092 When using fish shell on remote hosts, disable fancy formatting by
3093 adding the following to @file{~/.config/fish/config.fish}:
3097 function fish_prompt
3098 if test $TERM = "dumb"
3107 When using WinSSHD on remote hosts, @value{tramp} does not recognize
3108 the strange prompt settings.
3110 A similar problem exist with the iTerm2 shell integration, which sends
3111 proprietary escape codes when starting a shell. This can be
3112 suppressed by changing the respective integration snippet in your
3113 @file{~/.profile} like this:
3117 [ $TERM = "dumb" ] || \
3118 test -e "$@{HOME@}/.iterm2_shell_integration.bash" && \
3119 source "$@{HOME@}/.iterm2_shell_integration.bash"
3124 Echoed characters after login
3126 @value{tramp} suppresses echos from remote hosts with the
3127 @command{stty -echo} command. But sometimes it is too late to suppress
3128 welcome messages from the remote host containing harmful control
3129 characters. Using @option{sshx} or @option{scpx} methods can avoid
3130 this problem because they allocate a pseudo tty. @xref{Inline
3134 @value{tramp} stops transferring strings longer than 500 characters
3136 Set @code{tramp-chunksize} to 500 to get around this problem, which is
3137 related to faulty implementation of @code{process-send-string} on
3138 HP-UX, FreeBSD and Tru64 Unix systems. Consult the documentation for
3139 @code{tramp-chunksize} to see when this is necessary.
3141 Set @code{file-precious-flag} to @code{t} for files accessed by
3142 @value{tramp} so the file contents are checked using checksum by
3143 first saving to a temporary file.
3145 @pxref{Saving Buffers, , , elisp}
3153 (when (file-remote-p default-directory)
3154 (set (make-local-variable 'file-precious-flag) t))))
3161 @value{tramp} does not recognize if a @command{ssh} session hangs
3163 @command{ssh} sessions on the local host hang when the network is
3164 down. @value{tramp} cannot safely detect such hangs. The network
3165 configuration for @command{ssh} can be configured to kill such hangs
3166 with the following command in the @file{~/.ssh/config}:
3171 ServerAliveInterval 5
3177 @value{tramp} does not use default @command{ssh} @code{ControlPath}
3179 @value{tramp} overwrites @code{ControlPath} settings when initiating
3180 @command{ssh} sessions. @value{tramp} does this to fend off a stall
3181 if a master session opened outside the Emacs session is no longer
3182 open. That is why @value{tramp} prompts for the password again even
3183 if there is an @command{ssh} already open.
3185 @vindex tramp-ssh-controlmaster-options
3186 Some @command{ssh} versions support a @code{ControlPersist} option,
3187 which allows you to set the @code{ControlPath} provided the variable
3188 @code{tramp-ssh-controlmaster-options} is customized as follows:
3192 (setq tramp-ssh-controlmaster-options
3194 "-o ControlPath=/tmp/ssh-ControlPath-%%r@@%%h:%%p "
3195 "-o ControlMaster=auto -o ControlPersist=yes"))
3199 Note how "%r", "%h" and "%p" must be encoded as "%%r", "%%h" and
3202 @vindex tramp-use-ssh-controlmaster-options
3203 If the @file{~/.ssh/config} is configured appropriately for the above
3204 behavior, then any changes to @command{ssh} can be suppressed with
3205 this @code{nil} setting:
3209 (custom-set-variables
3210 '(tramp-use-ssh-controlmaster-options nil nil (tramp)))
3216 File name completion does not work with @value{tramp}
3218 @acronym{ANSI} escape sequences from the remote shell may cause errors
3219 in @value{tramp}'s parsing of remote buffers.
3221 To test if this is the case, open a remote shell and check if the output
3222 of @command{ls} is in color.
3224 To disable @acronym{ANSI} escape sequences from the remote hosts,
3225 disable @samp{--color=yes} or @samp{--color=auto} in the remote host's
3226 @file{.bashrc} or @file{.profile}. Turn this alias on and off to see
3227 if file name completion works.
3230 File name completion does not work in directories with large number of
3233 This may be related to globbing, which is the use of shell's ability
3234 to expand wild card specifications, such as @samp{*.c}. For
3235 directories with large number of files, globbing might exceed the
3236 shell's limit on length of command lines and hang. @value{tramp} uses
3239 To test if globbing hangs, open a shell on the remote host and then
3240 run @command{ls -d * ..?* > /dev/null}.
3242 When testing, ensure the remote shell is the same shell
3243 (@command{/bin/sh}, @command{ksh} or @command{bash}), that
3244 @value{tramp} uses when connecting to that host.
3248 How to get notified after @value{tramp} completes file transfers?
3250 Make Emacs beep after reading from or writing to the remote host with
3251 the following code in @file{~/.emacs} file.
3255 (defadvice tramp-handle-write-region
3256 (after tramp-write-beep-advice activate)
3257 "Make tramp beep after writing a file."
3263 (defadvice tramp-handle-do-copy-or-rename-file
3264 (after tramp-copy-beep-advice activate)
3265 "Make tramp beep after copying a file."
3271 (defadvice tramp-handle-insert-file-contents
3272 (after tramp-insert-beep-advice activate)
3273 "Make tramp beep after inserting a file."
3281 How to get a Visual Warning when working with @samp{root} privileges?
3282 Host indication in the mode line?
3284 Install @file{tramp-theme} from GNU ELPA via Emacs' Package Manager.
3285 Enable it via @kbd{M-x load-theme @key{RET} tramp}. Further
3286 customization is explained in user option
3287 @option{tramp-theme-face-remapping-alist}.
3291 Remote host does not understand default options for directory listing
3293 Emacs computes the @command{dired} options based on the local host but
3294 if the remote host cannot understand the same @command{ls} command,
3295 then set them with a hook as follows:
3300 'dired-before-readin-hook
3302 (when (file-remote-p default-directory)
3303 (setq dired-actual-switches "-al"))))
3309 Why is @file{~/.sh_history} file on the remote host growing?
3311 Due to the remote shell saving tilde expansions triggered by
3312 @value{tramp}, the history file is probably growing rapidly.
3313 @value{tramp} can suppress this behaviour with the user option
3314 @code{tramp-histfile-override}. When set to @code{t}, environment
3315 variable @env{HISTFILE} is unset, and environment variables
3316 @env{HISTFILESIZE} @env{HISTSIZE} are set to 0.
3318 Alternatively, @code{tramp-histfile-override} could be a string.
3319 Environment variable @env{HISTFILE} is set to this file name then. Be
3320 careful when setting to @file{/dev/null}; this might result in
3321 undesired results when using @command{bash} as remote shell.
3323 Another approach is to disable @value{tramp}'s handling of the
3324 @env{HISTFILE} at all by setting @code{tramp-histfile-override} to
3325 @code{nil}. In this case, saving history could be turned off by
3326 putting this shell code in the @file{.bashrc} or @file{.kshrc} file:
3330 if [ -f $HOME/.sh_history ] ; then
3331 /bin/rm $HOME/.sh_history
3333 if [ "$@{HISTFILE-unset@}" != "unset" ] ; then
3336 if [ "$@{HISTSIZE-unset@}" != "unset" ] ; then
3342 For @option{ssh}-based method, add the following line to your
3343 @file{~/.ssh/environment} file:
3351 How to shorten long file names when typing in @value{tramp}?
3353 Adapt several of these approaches to reduce typing. If the full name
3354 is @file{@trampfn{ssh,news@@news.my.domain,/opt/news/etc}}, then:
3359 Use default values for method name and user name:
3361 You can define default methods and user names for hosts,
3362 (@pxref{Default Method}, @pxref{Default User}):
3366 (custom-set-variables
3367 '(tramp-default-method "ssh" nil (tramp))
3368 '(tramp-default-user "news" nil (tramp)))
3372 The reduced typing: @kbd{C-x C-f @trampfn{-,news.my.domain,/opt/news/etc}}.
3374 @strong{Note} that there are some useful shortcuts already. Accessing
3375 your local host as @samp{root} user, is possible just by @kbd{C-x C-f
3379 Use configuration options of the access method:
3381 Programs used for access methods already offer powerful configurations
3382 (@pxref{Customizing Completion}). For @option{ssh}, configure the
3383 file @file{~/.ssh/config}:
3388 HostName news.my.domain
3393 The reduced typing: @kbd{C-x C-f @trampfn{ssh,xy,/opt/news/etc}}.
3395 Depending on the number of files in the directories, host names
3396 completion can further reduce key strokes: @kbd{C-x C-f
3397 @value{prefix}ssh@value{postfixhop}x @key{TAB}}.
3400 Use environment variables to expand long strings
3402 For long file names, set up environment variables that are expanded in
3403 the minibuffer. Environment variables are set either outside Emacs or
3404 inside Emacs with Lisp:
3407 (setenv "xy" "@trampfn{ssh,news@@news.my.domain,/opt/news/etc/}")
3410 The reduced typing: @kbd{C-x C-f $xy @key{RET}}.
3412 @strong{Note} that file name cannot be edited here because the
3413 environment variables are not expanded during editing in the
3416 @item Define own keys:
3418 Redefine another key sequence in Emacs for @kbd{C-x C-f}:
3423 [(control x) (control y)]
3428 "Find @value{tramp} file: "
3429 "@trampfn{ssh,news@@news.my.domain,/opt/news/etc/}"))))
3433 Simply typing @kbd{C-x C-y} would prepare minibuffer editing of file
3436 See @uref{https://www.emacswiki.org/emacs/TrampMode, the Emacs Wiki}
3437 for a more comprehensive example.
3440 Define own abbreviation (1):
3442 Abbreviation list expansion can be used to reduce typing long file names:
3447 'directory-abbrev-alist
3448 '("^/xy" . "@trampfn{ssh,news@@news.my.domain,/opt/news/etc/}"))
3452 The reduced typing: @kbd{C-x C-f /xy @key{RET}}.
3454 @strong{Note} that file name cannot be edited here because the
3455 environment variables are not expanded during editing in the
3459 Define own abbreviation (2):
3461 The @code{abbrev-mode} gives additional flexibility for editing in the
3466 (define-abbrev-table 'my-tramp-abbrev-table
3467 '(("xy" "@trampfn{ssh,news@@news.my.domain,/opt/news/etc/}")))
3472 'minibuffer-setup-hook
3475 (setq local-abbrev-table my-tramp-abbrev-table)))
3479 (defadvice minibuffer-complete
3480 (before my-minibuffer-complete activate)
3485 ;; If you use partial-completion-mode
3486 (defadvice PC-do-completion
3487 (before my-PC-do-completion activate)
3492 The reduced typing: @kbd{C-x C-f xy @key{TAB}}.
3494 The minibuffer expands for further editing.
3496 @item Use bookmarks:
3498 Use bookmarks to save @value{tramp} file names.
3500 @pxref{Bookmarks, , , emacs}.
3503 Upon visiting a location with @value{tramp}, save it as a bookmark with
3504 @kbd{@key{menu-bar} @key{edit} @key{bookmarks} @key{set}}.
3506 To revisit that bookmark:
3507 @kbd{@key{menu-bar} @key{edit} @key{bookmarks} @key{jump}}.
3509 @item Use recent files:
3511 @file{recentf} remembers visited places.
3513 @pxref{File Conveniences, , , emacs}.
3516 Keep remote file names in the recent list without have to check for
3517 their accessibility through remote access:
3523 Reaching recently opened files: @kbd{@key{menu-bar} @key{file}
3526 @item Use filecache:
3528 Since @file{filecache} remembers visited places, add the remote
3529 directory to the cache:
3533 @c `with-eval-after-load' has been introduced with Emacs 24.4. Shall
3534 @c be used when appropriate.
3535 (eval-after-load "filecache"
3536 '(file-cache-add-directory
3537 "@trampfn{ssh,news@@news.my.domain,/opt/news/etc/}"))
3541 Then use directory completion in the minibuffer with @kbd{C-x C-f
3546 @file{bbdb} has a built-in feature for Ange FTP files, which also
3547 works for @value{tramp} file names.
3549 @pxref{bbdb-ftp, Storing FTP sites in the BBDB, , bbdb}.
3552 Load @file{bbdb} in Emacs:
3561 Create a BBDB entry with @kbd{M-x bbdb-create-ftp-site}. Then specify
3562 a method and user name where needed. Examples:
3566 @kbd{M-x bbdb-create-ftp-site @key{RET}}
3567 @b{Ftp Site:} news.my.domain @key{RET}
3568 @b{Ftp Directory:} /opt/news/etc/ @key{RET}
3569 @b{Ftp Username:} ssh@value{postfixhop}news @key{RET}
3570 @b{Company:} @key{RET}
3571 @b{Additional Comments:} @key{RET}
3575 In BBDB buffer, access an entry by pressing the key @key{F}.
3579 Thanks to @value{tramp} users for contributing to these recipes.
3582 Why saved multi-hop file names do not work in a new Emacs session?
3584 When saving ad-hoc multi-hop @value{tramp} file names (@pxref{Ad-hoc
3585 multi-hops}) via bookmarks, recent files, filecache, bbdb, or another
3586 package, use the full ad-hoc file name including all hops, like
3587 @file{@trampfn{ssh,bird@@bastion|ssh@value{postfixhop}news.my.domain,/opt/news/etc}}.
3589 Alternatively, when saving abbreviated multi-hop file names
3590 @file{@trampfn{ssh,news@@news.my.domain,/opt/news/etc}}, the user
3591 option @option{tramp-save-ad-hoc-proxies} must be set non-@code{nil}
3596 How to connect to a remote Emacs session using @value{tramp}?
3598 Configure Emacs Client
3600 (@pxref{Emacs Server, , , emacs}).
3603 Then on the remote host, start the Emacs Server:
3608 (setq server-host (system-name)
3614 If @code{(system-name)} of the remote host cannot be resolved on the
3615 local host, use IP address instead.
3617 Copy from the remote host the resulting file
3618 @file{~/.emacs.d/server/server} to the local host, to the same
3621 Then start Emacs Client from the command line:
3624 emacsclient @trampfn{ssh,user@@host,/file/to/edit}
3627 @code{user} and @code{host} refer to the local host.
3629 To make Emacs Client an editor for other programs, use a wrapper
3630 script @file{emacsclient.sh}:
3635 emacsclient @trampfn{ssh,$(whoami)@@$(hostname --fqdn),$1}
3639 Then change the environment variable @env{EDITOR} to point to the
3643 export EDITOR=/path/to/emacsclient.sh
3648 How to disable other packages from calling @value{tramp}?
3650 There are packages that call @value{tramp} without the user ever
3651 entering a remote file name. Even without applying a remote file
3652 syntax, some packages enable @value{tramp} on their own. How can users
3653 disable such features.
3659 Disable @value{tramp} file name completion:
3662 (custom-set-variables '(ido-enable-tramp-completion nil))
3668 Disable remote directory tracking mode:
3671 (rlogin-directory-tracking-mode -1)
3677 How to disable @value{tramp}?
3681 To keep Ange FTP as default the remote files access package, set this
3685 (custom-set-variables '(tramp-default-method "ftp" nil (tramp)))
3689 To disable both @value{tramp} (and Ange FTP), set @code{tramp-mode} to
3690 @code{nil} in @file{.emacs}.
3693 (custom-set-variables '(tramp-mode nil nil (tramp)))
3697 To unload @value{tramp}, type @kbd{M-x tramp-unload-tramp}. Unloading
3698 @value{tramp} resets Ange FTP plugins also.
3703 @c For the developer
3704 @node Files directories and localnames
3705 @chapter How file names, directories and localnames are mangled and managed.
3708 * Localname deconstruction:: Splitting a localname into its component parts.
3709 * External packages:: Integrating with external Lisp packages.
3713 @node Localname deconstruction
3714 @section Splitting a localname into its component parts
3716 @value{tramp} package redefines lisp functions
3717 @code{file-name-directory} and @code{file-name-nondirectory} to
3718 accommodate the unique file naming syntax that @value{tramp} requires.
3720 The replacements dissect the file name, use the original handler for
3721 the localname, take that result, and then re-build the @value{tramp}
3722 file name. By relying on the original handlers for localnames,
3723 @value{tramp} benefits from platform specific hacks to the original
3727 @node External packages
3728 @section Integrating with external Lisp packages
3729 @subsection File name completion.
3731 Sometimes, it is not convenient to open a new connection to a remote
3732 host, including entering the password and alike. For example, this is
3733 nasty for packages providing file name completion. Such a package
3734 could signal to @value{tramp}, that they don't want it to establish a
3735 new connection. Use the variable @code{non-essential} temporarily and
3736 bind it to non-@code{nil} value.
3740 (let ((non-essential t))
3746 @subsection File attributes cache.
3748 Keeping a local cache of remote file attributes in sync with the
3749 remote host is a time-consuming operation. Flushing and re-querying
3750 these attributes can tax @value{tramp} to a grinding halt on busy
3753 To get around these types of slow-downs in @value{tramp}'s
3754 responsiveness, set the @code{process-file-side-effects} to @code{nil}
3755 to stop @value{tramp} from flushing the cache. This is helpful in
3756 situations where callers to @code{process-file} know there are no file
3757 attribute changes. The let-bind form to accomplish this:
3761 (let (process-file-side-effects)
3766 For asynchronous processes, @value{tramp} uses a process sentinel to
3767 flush file attributes cache. When callers to @code{start-file-process}
3768 know beforehand no file attribute changes are expected, then the
3769 process sentinel should be set to the default state. In cases where
3770 the caller defines its own process sentinel, @value{tramp}'s process
3771 sentinel is overwritten. The caller can still flush the file
3772 attributes cache in its process sentinel with this code:
3776 (unless (memq (process-status proc) '(run open))
3777 (dired-uncache remote-directory))
3781 Since @value{tramp} traverses subdirectories starting with the
3782 root-directory, it is most likely sufficient to make the
3783 @code{default-directory} of the process buffer as the root directory.
3786 @node Traces and Profiles
3787 @chapter How to Customize Traces
3789 @value{tramp} messages are raised with verbosity levels ranging from 0
3790 to 10. @value{tramp} does not display all messages; only those with a
3791 verbosity level less than or equal to @code{tramp-verbose}.
3793 The verbosity levels are
3795 @w{ 0} silent (no @value{tramp} messages at all)
3796 @*@indent @w{ 1} errors
3797 @*@indent @w{ 2} warnings
3798 @*@indent @w{ 3} connection to remote hosts (default verbosity)
3799 @*@indent @w{ 4} activities
3800 @*@indent @w{ 5} internal
3801 @*@indent @w{ 6} sent and received strings
3802 @*@indent @w{ 7} file caching
3803 @*@indent @w{ 8} connection properties
3804 @*@indent @w{ 9} test commands
3805 @*@indent @w{10} traces (huge)
3807 With @code{tramp-verbose} greater than or equal to 4, messages are
3808 also written to a @value{tramp} debug buffer. Such debug buffers are
3809 essential to bug and problem analyses. For @value{tramp} bug reports,
3810 set the @code{tramp-verbose} level to 6 (@pxref{Bug Reports}).
3812 The debug buffer is in
3814 @ref{Outline Mode, , , emacs}.
3819 In this buffer, messages can be filtered by their level. To see
3820 messages up to verbosity level 5, enter @kbd{C-u 6 C-c C-q}.
3822 Other navigation keys are described in
3823 @ref{Outline Visibility, , , emacs}.
3826 @value{tramp} handles errors internally. But to get a Lisp backtrace,
3827 both the error and the signal have to be set as follows:
3831 (setq debug-on-error t
3836 If @code{tramp-verbose} is greater than or equal to 10, Lisp
3837 backtraces are also added to the @value{tramp} debug buffer in case of
3840 To enable stepping through @value{tramp} function call traces, they
3841 have to be specifically enabled as shown in this code:
3846 (dolist (elt (all-completions "tramp-" obarray 'functionp))
3847 (trace-function-background (intern elt)))
3848 (untrace-function 'tramp-read-passwd)
3852 The buffer @file{*trace-output*} contains the output from the function
3853 call traces. Disable @code{tramp-read-passwd} to stop password
3854 strings from being written to @file{*trace-output*}.
3857 @node GNU Free Documentation License
3858 @appendix GNU Free Documentation License
3859 @include doclicense.texi
3862 @node Function Index
3863 @unnumbered Function Index
3867 @node Variable Index
3868 @unnumbered Variable Index
3873 @unnumbered Concept Index
3880 @c * Say something about the .login and .profile files of the remote
3882 @c * Explain how tramp.el works in principle: open a shell on a remote
3883 @c host and then send commands to it.
3884 @c * Consistent small or capitalized words especially in menus.