This is tramp.info, produced by makeinfo version 4.6 from tramp.texi.

Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation,
Inc.

     Permission is granted to copy, distribute and/or modify this
     document under the terms of the GNU Free Documentation License,
     Version 1.1 or any later version published by the Free Software
     Foundation; with no Invariant Sections, with the Front-Cover texts
     being "A GNU Manual", and with the Back-Cover Texts as in (a)
     below.  A copy of the license is included in the section entitled
     "GNU Free Documentation License" in the Emacs manual.

     (a) The FSF's Back-Cover Text is: "You have freedom to copy and
     modify this GNU Manual, like GNU software.  Copies published by
     the Free Software Foundation raise funds for GNU development."

     This document is part of a collection distributed under the GNU
     Free Documentation License.  If you want to distribute this
     document separately from the collection, you can do so by adding a
     copy of the license to the document, as described in section 6 of
     the license.
   
INFO-DIR-SECTION Emacs
START-INFO-DIR-ENTRY
* TRAMP: (tramp).                Transparent Remote Access, Multiple Protocol
                                 Emacs remote file access via rsh and rcp.
END-INFO-DIR-ENTRY


File: tramp.info,  Node: Top,  Next: Overview,  Prev: (dir),  Up: (dir)

TRAMP version 2.0.36 User Manual
********************************

This file documents TRAMP version 2.0.36, a remote file editing package
for Emacs.

   TRAMP stands for `Transparent Remote (file) Access, Multiple
Protocol'.  This package provides remote file editing, similar to
Ange-FTP.

   The difference is that Ange-FTP uses FTP to transfer files between
the local and the remote host, whereas TRAMP uses a combination of
`rsh' and `rcp' or other work-alike programs, such as `ssh'/`scp'.

   You can find the latest version of this document on the web at
`http://www.freesoftware.fsf.org/tramp/'.

   There is a mailing list for TRAMP, available at
<tramp-devel@mail.freesoftware.fsf.org>, and archived at
`http://www.mail-archive.com/emacs-rcp@ls6.cs.uni-dortmund.de/' as well
as the usual Savannah archives.

Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation,
Inc.

     Permission is granted to copy, distribute and/or modify this
     document under the terms of the GNU Free Documentation License,
     Version 1.1 or any later version published by the Free Software
     Foundation; with no Invariant Sections, with the Front-Cover texts
     being "A GNU Manual", and with the Back-Cover Texts as in (a)
     below.  A copy of the license is included in the section entitled
     "GNU Free Documentation License" in the Emacs manual.

     (a) The FSF's Back-Cover Text is: "You have freedom to copy and
     modify this GNU Manual, like GNU software.  Copies published by
     the Free Software Foundation raise funds for GNU development."

     This document is part of a collection distributed under the GNU
     Free Documentation License.  If you want to distribute this
     document separately from the collection, you can do so by adding a
     copy of the license to the document, as described in section 6 of
     the license.
   
* Menu:

* Overview::                    What TRAMP can and cannot do.

For the end user:

* Obtaining TRAMP::             How to obtain TRAMP.
* History::                     History of TRAMP.
* Configuration::               Configuring TRAMP for use.
* Usage::                       An overview of the operation of TRAMP.
* Bug Reports::                 Reporting Bugs and Problems.
* Frequently Asked Questions::  Questions and answers from the mailing list.
* Concept Index::               An item for each concept

For the developer:

* Version Control::             The inner workings of remote version control.
* Files directories and localnames::  How file names, directories and localnames are mangled and managed.
* Issues::                      Debatable Issues and What Was Decided.

 --- The Detailed Node Listing ---

Configuring TRAMP for use

* Connection types::            Types of connections made to remote machines.
* Inline methods::              Inline methods.
* External transfer methods::   External transfer methods.
* Multi-hop Methods::           Connecting to a remote host using multiple hops.
* Default Method::              Selecting a default method.
* Customizing Methods::         Using Non-Standard Methods.
* Customizing Completion::      Selecting config files for user/host name completion.
* Remote Programs::             How TRAMP finds and uses programs on the remote machine.
* Remote shell setup::          Remote shell setup hints.
* Windows setup hints::         Issues with Cygwin ssh.
* Auto-save and Backup::        Auto-save and Backup.

Using TRAMP

* Filename Syntax::             TRAMP filename conventions.
* Multi-hop filename syntax::   Multi-hop filename conventions.
* Filename completion::         Filename completion.
* Dired::                       Dired.

The inner workings of remote version control

* Version Controlled Files::    Determining if a file is under version control.
* Remote Commands::             Executing the version control commands on the remote machine.
* Changed workfiles::           Detecting if the working file has changed.
* Checking out files::          Bringing the workfile out of the repository.
* Miscellaneous Version Control::  Things related to Version Control that don't fit elsewhere.

Things related to Version Control that don't fit elsewhere

* Remote File Ownership::       How VC determines who owns a workfile.
* Back-end Versions::           How VC determines what release your RCS is.

How file names, directories and localnames are mangled and managed

* Localname deconstruction::    Breaking a localname into its components.


File: tramp.info,  Node: Overview,  Next: Obtaining TRAMP,  Prev: Top,  Up: Top

An overview of TRAMP
********************

After the installation of TRAMP into your Emacs, you will be able to
access files on remote machines as though they were local.  Access to
the remote file system for editing files, version control, and `dired'
are transparently enabled.

   Your access to the remote machine can be with the `rsh', `rlogin',
`telnet' programs or with any similar connection method.  This
connection must pass ASCII successfully to be usable but need not be
8-bit clean.

   The package provides support for `ssh' connections out of the box,
one of the more common uses of the package.  This allows relatively
secure access to machines, especially if `ftp' access is disabled.

   The majority of activity carried out by TRAMP requires only that the
remote login is possible and is carried out at the terminal.  In order
to access remote files TRAMP needs to transfer their content to the
local machine temporarily.

   TRAMP can transfer files between the machines in a variety of ways.
The details are easy to select, depending on your needs and the
machines in question.

   The fastest transfer methods (for large files) rely on a remote file
transfer package such as `rcp', `scp' or `rsync'.  The use of these
methods is only possible if the file copy command does not ask for a
password for the remote machine.

   If the remote copy methods are not suitable for you, TRAMP also
supports the use of encoded transfers directly through the shell.  This
requires that the `mimencode' or `uuencode' tools are available on the
remote machine.  These methods are generally faster for small files.

   Within these limitations, TRAMP is quite powerful.  It is worth
noting that, as of the time of writing, it is far from a polished
end-user product.  For a while yet you should expect to run into rough
edges and problems with the code now and then.

   It is finished enough that the developers use it for day to day work
but the installation and setup can be a little difficult to master, as
can the terminology.

   TRAMP is still under active development and any problems you
encounter, trivial or major, should be reported to the TRAMP developers.
*Note Bug Reports::.

Behind the scenes
.................

This section tries to explain what goes on behind the scenes when you
access a remote file through TRAMP.

   Suppose you type `C-x C-f' and enter part of an TRAMP file name,
then hit `<TAB>' for completion.  Suppose further that this is the
first time that TRAMP is invoked for the host in question.  Here's what
happens:

   * TRAMP discovers that it needs a connection to the host.  So it
     invokes `telnet HOST' or `rsh HOST -l USER' or a similar tool to
     connect to the remote host.  Communication with this process
     happens through an Emacs buffer, that is, the output from the
     remote end goes into a buffer.

   * The remote host may prompt for a login name (for `telnet').  The
     login name is given in the file name, so TRAMP sends the login
     name and a newline.

   * The remote host may prompt for a password or pass phrase (for
     `rsh' or for `telnet' after sending the login name).  TRAMP
     displays the prompt in the minibuffer, asking you for the password
     or pass phrase.

     You enter the password or pass phrase.  TRAMP sends it to the
     remote host, followed by a newline.

   * TRAMP now waits for the shell prompt or for a message that the
     login failed.

     If TRAMP sees neither of them after a certain period of time (a
     minute, say), then it issues an error message saying that it
     couldn't find the remote shell prompt and shows you what the
     remote host has sent.

     If TRAMP sees a `login failed' message, it tells you so, aborts
     the login attempt and allows you to try again.

   * Suppose that the login was successful and TRAMP sees the shell
     prompt from the remote host.  Now TRAMP invokes `/bin/sh' because
     Bourne shells and C shells have different command syntaxes.(1)

     After the Bourne shell has come up, TRAMP sends a few commands to
     ensure a good working environment.  It turns off echoing, it sets
     the shell prompt, and a few other things.

   * Now the remote shell is up and it good working order.  Remember,
     what was supposed to happen is that TRAMP tries to find out what
     files exist on the remote host so that it can do filename
     completion.

     So, TRAMP basically issues `cd' and `ls' commands and also
     sometimes `echo' with globbing.  Another command that is often
     used is `test' to find out whether a file is writable or a
     directory or the like.  The output of each command is parsed for
     the necessary operation.

   * Suppose you are finished with filename completion, have entered
     `C-x C-f', a full file name and hit `<RET>'.  Now comes the time to
     transfer the file contents from the remote host to the local host
     so that you can edit them.

     See above for an explanation of how TRAMP transfers the file
     contents.

     For inline transfers, TRAMP issues a command like `mimencode -b
     /path/to/remote/file', waits until the output has accumulated in
     the buffer that's used for communication, then decodes that output
     to produce the file contents.

     For out-of-band transfers, TRAMP issues a command like the
     following:
          rcp user@host:/path/to/remote/file /tmp/tramp.4711
     It then reads the local temporary file `/tmp/tramp.4711' into a
     buffer and deletes the temporary file.

   * You now edit the buffer contents, blithely unaware of what has
     happened behind the scenes.  (Unless you have read this section,
     that is.)  When you are finished, you type `C-x C-s' to save the
     buffer.

   * Again, TRAMP transfers the file contents to the remote host either
     inline or out-of-band.  This is the reverse of what happens when
     reading the file.


   I hope this has provided you with a basic overview of what happens
behind the scenes when you open a file with TRAMP.

   ---------- Footnotes ----------

   (1) Invoking `/bin/sh' will fail if your login shell doesn't
recognize `exec /bin/sh' as a valid command.  Maybe you use the Scheme
shell `scsh'...


File: tramp.info,  Node: Obtaining TRAMP,  Next: History,  Prev: Overview,  Up: Top

Obtaining TRAMP.
****************

TRAMP is freely available on the Internet and the latest release may be
downloaded from `http://savannah.nongnu.org/download/tramp/'. This
release includes the full documentation and code for TRAMP, suitable
for installation.  But Emacs (21.4 or later) includes TRAMP already,
and there is a TRAMP package for XEmacs, as well.  So maybe it is
easier to just use those.  But if you want the bleeding edge, read
on......

   For the especially brave, TRAMP is available from CVS.  The CVS
version is the latest version of the code and may contain incomplete
features or new issues. Use these versions at your own risk.

   Instructions for obtaining the latest development version of TRAMP
from CVS can be found by going to the Savannah project page at the
following URL and then clicking on the CVS link in the navigation bar
at the top.

`http://savannah.gnu.org/projects/tramp/'

Or follow the example session below:

     ] *cd ~/emacs*
     ] *cvs -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/tramp login*
     
     (Logging in to anoncvs@subversions.gnu.org)
     CVS password: *(just hit RET here)*
     ...
     
     ] *cvs -z3 -d:pserver:anoncvs@subversions.gnu.org:/cvsroot/tramp co tramp*

You should now have a directory `~/emacs/tramp' containing the latest
version of TRAMP. You can fetch the latest updates from the repository
by issuing the command:

     ] *cd ~/emacs/tramp*
     ] *cvs update -d*

Once you've got updated files from the CVS repository, you need to run
`autoconf' in order to get an up-to-date `configure' script:

     ] *cd ~/emacs/tramp*
     ] *autoconf*


File: tramp.info,  Node: History,  Next: Configuration,  Prev: Obtaining TRAMP,  Up: Top

History of TRAMP
****************

Development was started end of November 1998.  The package was called
`rssh.el', back then.  It only provided one method to access a file,
using `ssh' to log in to a remote host and using `scp' to transfer the
file contents.  After a while, the name was changed to `rcp.el', and
now it's TRAMP.  Along the way, many more methods for getting a remote
shell and for transferring the file contents were added.  Support for
VC was added.

   The most recent addition of major features were the multi-hop methods
added in April 2000 and the unification of TRAMP and Ange-FTP filenames
in July 2002.


File: tramp.info,  Node: Configuration,  Next: Usage,  Prev: History,  Up: Top

Configuring TRAMP for use
*************************

TRAMP is (normally) fully functional when it is initially installed.
It is initially configured to use the `ssh' program to connect to the
remote host and to use base-64 encoding (on the remote host, via
`mimencode', and on the local host via the built-in support for base-64
encoding in Emacs).

   On some hosts, there are problems with opening a connection.  These
are related to the behavior of the remote shell.  See *Note Remote
shell setup::, for details on this.

   If you do not wish to use these commands to connect to the remote
host, you should change the default connection and transfer method that
TRAMP uses.  There are several different methods that TRAMP can use to
connect to remote machines and transfer files (*note Connection
types::).

* Menu:

* Connection types::            Types of connections made to remote machines.
* Inline methods::              Inline methods.
* External transfer methods::   External transfer methods.
* Multi-hop Methods::           Connecting to a remote host using multiple hops.
* Default Method::              Selecting a default method.
* Customizing Methods::         Using Non-Standard Methods.
* Customizing Completion::      Selecting config files for user/host name completion.
* Remote Programs::             How TRAMP finds and uses programs on the remote machine.
* Remote shell setup::          Remote shell setup hints.
* Windows setup hints::         Issues with Cygwin ssh.
* Auto-save and Backup::        Auto-save and Backup.


File: tramp.info,  Node: Connection types,  Next: Inline methods,  Up: Configuration

Types of connections made to remote machines.
=============================================

There are two basic types of transfer methods, each with its own
advantages and limitations.  Both types of connection make use of a
remote shell access program such as `rsh', `ssh' or `telnet' to connect
to the remote machine.

   This connection is used to perform many of the operations that TRAMP
requires to make the remote file system transparently accessible from
the local machine. It is only when visiting files that the methods
differ.

   Loading or saving a remote file requires that the content of the file
be transfered between the two machines. The content of the file can be
transfered over the same connection used to log in to the remote
machine or the file can be transfered through another connection using
a remote copy program such as `rcp', `scp' or `rsync'.  The former are
called "inline methods", the latter are called "out-of-band methods" or
"external transfer methods" ("external methods" for short).

   The performance of the external transfer methods is generally better
than that of the inline methods, at least for large files.  This is
caused by the need to encode and decode the data when transferring
inline.

   The one exception to this rule are the `scp' based transfer methods.
While these methods do see better performance when actually
transferring files, the overhead of the cryptographic negotiation at
startup may drown out the improvement in file transfer times.

   External transfer methods do require that the remote copy command is
not interactive -- that is, the command does not prompt you for a
password.  If you cannot perform remote copies without a password, you
will need to use an inline transfer method to work with TRAMP.

   A variant of the inline methods are the "multi-hop methods".  These
methods allow you to connect a remote host using a number `hops', each
of which connects to a different host.  This is useful if you are in a
secured network where you need to go through a bastion host to connect
to the outside world.


File: tramp.info,  Node: Inline methods,  Next: External transfer methods,  Prev: Connection types,  Up: Configuration

Inline methods
==============

The inline methods in TRAMP are quite powerful and can work in
situations where you cannot use an external transfer program to connect.
Inline methods are the only methods that work when connecting to the
remote machine via telnet.  (There are also strange inline methods which
allow you to transfer files between _user identities_ rather than
hosts, see below.)

   These methods depend on the existence of a suitable encoding and
decoding command on remote machine.  Locally, TRAMP may be able to use
features of Emacs to decode and encode the files or it may require
access to external commands to perform that task.

   TRAMP checks the availability and usability of commands like
`mimencode' (part of the `metamail' package) or `uuencode' on the
remote host.  The first reliable command will be used.  The search path
can be customized, see *Note Remote Programs::.

   If both commands aren't available on the remote host, TRAMP
transfers a small piece of Perl code to the remote host, and tries to
apply it for encoding and decoding.

`rsh'
     Connect to the remote host with `rsh'.  Due to the unsecure
     connection it is recommended for very local host topology only.

     On operating systems which provide the command `remsh' instead of
     `rsh', you can use the method `remsh'.  This is true for HP-UX or
     Cray UNICOS, for example.

`ssh'
     Connect to the remote host with `ssh'.  This is identical to the
     previous option except that the `ssh' package is used, making the
     connection more secure.

     There are also two variants, `ssh1' and `ssh2', that call `ssh -1'
     and `ssh -2', respectively.  This way, you can explicitly select
     whether you want to use the SSH protocol version 1 or 2 to connect
     to the remote host.  (You can also specify in `~/.ssh/config', the
     SSH configuration file, which protocol should be used, and use the
     regular `ssh' method.)

     Two other variants, `ssh1_old' and `ssh2_old', use the `ssh1' and
     `ssh2' commands explicitly.  If you don't know what these are, you
     do not need these options.

     All the methods based on `ssh' have an additional kludgy feature:
     you can specify a host name which looks like `host#42' (the real
     host name, then a hash sign, then a port number).  This means to
     connect to the given host but to also pass `-p 42' as arguments to
     the `ssh' command.

`telnet'
     Connect to the remote host with `telnet'.  This is as unsecure as
     the `rsh' method.

`su'
     This method does not connect to a remote host at all, rather it
     uses the `su' program to allow you to edit files as another user.

`sudo'
     This is similar to the `su' method, but it uses `sudo' rather than
     `su' to become a different user.

     Note that `sudo' must be configured to allow you to start a shell
     as the user.  It would be nice if it was sufficient if `ls' and
     `mimencode' were allowed, but that is not easy to implement, so I
     haven't got around to it, yet.

`sshx'
     As you expect, this is similar to `ssh', only a little different.
     Whereas `ssh' opens a normal interactive shell on the remote host,
     this option uses `ssh -t -t HOST -l USER /bin/sh' to open a
     connection.  This is useful for users where the normal login shell
     is set up to ask them a number of questions when logging in.  This
     procedure avoids these questions, and just gives TRAMP a
     more-or-less `standard' login shell to work with.

     Note that this procedure does not eliminate questions asked by
     `ssh' itself.  For example, `ssh' might ask "Are you sure you want
     to continue connecting?" if the host key of the remote host is not
     known.  TRAMP does not know how to deal with such a question
     (yet), therefore you will need to make sure that you can log in
     without such questions.

     This is also useful for Windows users where `ssh', when invoked
     from an Emacs buffer, tells them that it is not allocating a
     pseudo tty.  When this happens, the login shell is wont to not
     print any shell prompt, which confuses TRAMP mightily.  For reasons
     unknown, some Windows ports for `ssh' (maybe the Cygwin one)
     require the doubled `-t' option.

     This supports the `-p' kludge.

`krlogin'
     This method is also similar to `ssh'.  It only uses the `krlogin
     -x' command to log in to the remote host.

`plink'
     This method is mostly interesting for Windows users using the PuTTY
     implementation of SSH.  It uses `plink -ssh' to log in to the
     remote host.

     Additionally, the method `plink1' is provided, which calls `plink
     -1 -ssh' in order to use SSH protocol version 1 explicitely.

     CCC: Do we have to connect to the remote host once from the command
     line to accept the SSH key?  Maybe this can be made automatic?

     CCC: Does `plink' support the `-p' option?  TRAMP will support
     that, anyway.



File: tramp.info,  Node: External transfer methods,  Next: Multi-hop Methods,  Prev: Inline methods,  Up: Configuration

External transfer methods
=========================

The external transfer methods operate through multiple channels, using
the remote shell connection for many actions while delegating file
transfers to an external transfer utility.

   This saves the overhead of encoding and decoding that multiplexing
the transfer through the one connection has with the inline methods.

   If you want to use an external transfer method you _must_ be able to
execute the transfer utility to copy files to and from the remote
machine without any interaction.

   This means that you will need to use `ssh-agent' if you use the
`scp' program for transfers, or maybe your version of `scp' accepts a
password on the command line.(1) If you use `rsync' via `ssh' then the
same rule must apply to that connection.

   If you cannot get `scp' to run without asking for a password but
would still like to use `ssh' to secure your connection, have a look at
the `ssh' based inline methods.

`rcp'  --  `rsh' and `rcp'
     This method uses the `rsh' and `rcp' commands to connect to the
     remote machine and transfer files.  This is probably the fastest
     connection method available.

     The alternative method `remcp' uses the `remsh' and `rcp'
     commands.  It should be applied on machines where `remsh' is used
     instead of `rsh'.

`scp'  --  `ssh' and `scp'
     Using `ssh' to connect to the remote host and `scp' to transfer
     files between the machines is the best method for securely
     connecting to a remote machine and accessing files.

     The performance of this option is also quite good. It may be
     slower than the inline methods when you often open and close small
     files however.  The cost of the cryptographic handshake at the
     start of an `scp' session can begin to absorb the advantage that
     the lack of encoding and decoding presents.

     There are also two variants, `scp1' and `scp2', that call `ssh -1'
     and `ssh -2', respectively.  This way, you can explicitly select
     whether you want to use the SSH protocol version 1 or 2 to connect
     to the remote host.  (You can also specify in `~/.ssh/config', the
     SSH configuration file, which protocol should be used, and use the
     regular `ssh' method.)

     Two other variants, `scp1_old' and `scp2_old', use the `ssh1' and
     `ssh2' commands explicitly.  If you don't know what these are, you
     do not need these options.

     All the `ssh' based methods support the kludgy `-p' feature where
     you can specify a port number to connect to in the host name.  For
     example, the host name `host#42' tells TRAMP to specify `-p 42' in
     the argument list for `ssh'.

`rsync'  --  `ssh' and `rsync'
     Using the `ssh' command to connect securely to the remote machine
     and the `rsync' command to transfer files is almost identical to
     the `scp' method.

     While `rsync' performs much better than `scp' when transferring
     files that exist on both hosts, this advantage is lost if the file
     exists only on one side of the connection.

     The `rsync' based method may be considerably faster than the `rcp'
     based methods when writing to the remote system. Reading files to
     the local machine is no faster than with a direct copy.

     This method supports the `-p' hack.

`scpx' -- `ssh' and `scp'
     As you expect, this is similar to `scp', only a little different.
     Whereas `scp' opens a normal interactive shell on the remote host,
     this option uses `ssh -t -t HOST -l USER /bin/sh' to open a
     connection.  This is useful for users where the normal login shell
     is set up to ask them a number of questions when logging in.  This
     procedure avoids these questions, and just gives TRAMP a
     more-or-less `standard' login shell to work with.

     This is also useful for Windows users where `ssh', when invoked
     from an Emacs buffer, tells them that it is not allocating a
     pseudo tty.  When this happens, the login shell is wont to not
     print any shell prompt, which confuses TRAMP mightily.  Maybe this
     applies to the Cygwin port of SSH.

     This method supports the `-p' hack.

`pscp' -- `plink' and `pscp'
     This method is similar to `scp', but it uses the `plink' command
     to connect to the remote host, and it uses `pscp' for transferring
     the files.  These programs are part of PuTTY, an SSH
     implementation for Windows.

     CCC: Does `plink' support the `-p' hack?

`fcp' -- `fsh' and `fcp'
     This method is similar to `scp', but it uses the `fsh' command to
     connect to the remote host, and it uses `fcp' for transferring the
     files.  `fsh/fcp' are a front-end for `ssh' which allow for
     reusing the same `ssh' session for submitting several commands.
     This avoids the startup overhead of `scp' (which has to establish
     a secure connection whenever it is called).  Note, however, that
     you can also use one of the inline methods to achieve a similar
     effect.

     This method uses the command `fsh HOST -l USER /bin/sh -i' to
     establish the connection, it does not work to just say `fsh HOST
     -l USER'.

     There is no inline method using `fsh' as the multiplexing provided
     by the program is not very useful in our context.  TRAMP opens
     just one connection to the remote host and then keeps it open,
     anyway.

`ftp'
     This is not a native TRAMP method. Instead of, it forwards all
     requests to Ange-FTP.

`smb' -- `smbclient'
     This is another not natural TRAMP method.  It uses the `smbclient'
     command on different Unices in order to connect to an SMB server.
     An SMB server might be a Samba (or CIFS) server on another UNIX
     host or, more interesting, a host running MS Windows.  So far, it
     is tested towards MS Windows NT, MS Windows 2000, and MS Windows
     XP.

     The first directory in the localname must be a share name on the
     remote host.  Remember, that the `$' character in which default
     shares usually end, must be written `$$' due to environment
     variable substitution in file names.  If no share name is given
     (i.e. remote directory `/'), all available shares are listed.

     Since authorization is done on share level, you will be prompted
     always for a password if you access another share on the same host.
     Due to security reasons, the password is not cached.

     MS Windows uses for authorization both a user name and a domain
     name.  Because of this, the TRAMP syntax has been extended: you can
     specify a user name which looks like `user%domain' (the real user
     name, then a percent sign, then the domain name).  So, to connect
     to the machine `melancholia' as user `daniel' of the domain
     `BIZARRE', and edit `.emacs' in the home directory (share
     `daniel$') I would specify the filename
     `/smb:daniel%BIZARRE@melancholia:/daniel$$/.emacs'.

     The domain name as well as the user name are optional.  If no user
     name is specified at all, the anonymous user (without password
     prompting) is assumed.  This is different from all other TRAMP
     methods, where in such a case the local user name is taken.

     The `smb' method supports the `-p' hack.

     *Please note:* If Emacs runs locally under MS Windows, this method
     isn't available.  Instead of, you can use UNC file names like
     `//melancholia/daniel$$/.emacs'.  The only disadvantage is that
     there's no possibility to specify another user name.


   ---------- Footnotes ----------

   (1) PuTTY's `pscp' allows you to specify the password on the command
line.


File: tramp.info,  Node: Multi-hop Methods,  Next: Default Method,  Prev: External transfer methods,  Up: Configuration

Connecting to a remote host using multiple hops
===============================================

Sometimes, the methods described before are not sufficient.  Sometimes,
it is not possible to connect to a remote host using a simple command.
For example, if you are in a secured network, you might have to log in
to a `bastion host' first before you can connect to the outside world.
Of course, the target host may also require a bastion host.  The format
of multi-hop filenames is slightly different than the format of normal
TRAMP methods.

   A multi-hop file name specifies a method, a number of hops, and a
localname (path name on the remote system).  The method name is always
`multi'.

   Each hop consists of a "hop method" specification, a user name and a
host name.  The hop method can be an inline method only.  The following
hop methods are (currently) available:

`telnet'
     Uses the well-known `telnet' program to connect to the host.
     Whereas user name and host name are supplied in the file name, the
     user is queried for the password.

`rsh'
     This uses `rsh' to connect to the host.  You do not need to enter
     a password unless `rsh' explicitly asks for it.

     The variant `remsh' uses the `remsh' command.  It should be
     applied on machines where `remsh' is used instead of `rsh'.

`ssh'
     This uses `ssh' to connect to the host.  You might have to enter a
     password or a pass phrase.

`su'
     This method does not actually contact a different host, but it
     allows you to become a different user on the host you're currently
     on.  This might be useful if you want to edit files as root, but
     the remote host does not allow remote root logins.  In this case
     you can use `telnet', `rsh' or `ssh' to connect to the remote host
     as a non-root user, then use an `su' hop to become root.  But `su'
     need not be the last hop in a sequence, you could also use it
     somewhere in the middle, if the need arises.

     Even though you _must_ specify both user and host with an `su'
     hop, the host name is ignored and only the user name is used.

`sudo'
     This is similar to the `su' hop, except that it uses `sudo' rather
     than `su' to become a different user.


   Some people might wish to use port forwarding with `ssh' or maybe
they have to use a nonstandard port.  This can be accomplished by
putting a stanza in `~/.ssh/config' for the account which specifies a
different port number for a certain host name.  But it can also be
accomplished within TRAMP, by adding a multi-hop method.  For example:

     (add-to-list
      'tramp-multi-connection-function-alist
      '("sshf" tramp-multi-connect-rlogin "ssh %h -l %u -p 4400%n"))

   Now you can use an `sshf' hop which connects to port 4400 instead of
the standard port.


File: tramp.info,  Node: Default Method,  Next: Customizing Methods,  Prev: Multi-hop Methods,  Up: Configuration

Selecting a default method
==========================

When you select an appropriate transfer method for your typical usage
you should set the variable TRAMP-DEFAULT-METHOD to reflect that
choice.  This variable controls which method will be used when a method
is not specified in the TRAMP file name.  For example:

     (setq tramp-default-method "scp")

   You can also specify different methods for certain user/host
combinations, via the variable TRAMP-DEFAULT-METHOD-ALIST.  For
example, the following two lines specify to use the `ssh' method for
all user names matching `john' and the `rsync' method for all host
names matching `lily'.  The third line specifies to use the `su' method
for the user `root' on the machine `localhost'.

     (add-to-list 'tramp-default-method-alist '("" "john" "ssh"))
     (add-to-list 'tramp-default-method-alist '("lily" "" "rsync"))
     (add-to-list 'tramp-default-method-alist
                  '("\\`localhost\\'" "\\`root\\'" "su"))

See the documentation for the variable TRAMP-DEFAULT-METHOD-ALIST for
more details.

   External transfer methods are normally preferable to inline transfer
methods, giving better performance. They may not be useful if you use
many remote machines where you cannot log in without a password.

   *Note Inline methods::.  *Note External transfer methods::.  *Note
Multi-hop Methods::.

   Another consideration with the selection of transfer methods is the
environment you will use them in and, especially when used over the
Internet, the security implications of your preferred method.

   The `rsh' and `telnet' methods send your password as plain text as
you log in to the remote machine, as well as transferring the files in
such a way that the content can easily be read from other machines.

   If you need to connect to remote systems that are accessible from the
Internet, you should give serious thought to using `ssh' based methods
to connect. These provide a much higher level of security, making it a
non-trivial exercise for someone to obtain your password or read the
content of the files you are editing.


File: tramp.info,  Node: Customizing Methods,  Next: Customizing Completion,  Prev: Default Method,  Up: Configuration

Using Non-Standard Methods
==========================

There is a variable `tramp-methods' which you can change if the
predefined methods don't seem right.

   For the time being, I'll refer you to the Lisp documentation of that
variable, accessible with `C-h v tramp-methods <RET>'.


File: tramp.info,  Node: Customizing Completion,  Next: Remote Programs,  Prev: Customizing Methods,  Up: Configuration

Selecting config files for user/host name completion
====================================================

The variable `tramp-completion-function-alist' is intended to customize
which files are taken into account for user and host name completion
(*note Filename completion::).  For every method, it keeps a set of
configuration files, accompanied by a Lisp function able to parse that
file.  Entries in `tramp-completion-function-alist' have the form
(METHOD PAIR1 PAIR2 ...).

   Each PAIR is composed of (FUNCTION FILE).  FUNCTION is responsible
to extract user names and host names from FILE for completion.  There
are two functions which access this variable:

 - Function: tramp-get-completion-function method
     This function returns the list of completion functions for METHOD.

     Example:
          (tramp-get-completion-function "rsh")
          
               => ((tramp-parse-rhosts "/etc/hosts.equiv")
                   (tramp-parse-rhosts "~/.rhosts"))

 - Function: tramp-set-completion-function method function-list
     This function sets FUNCTION-LIST as list of completion functions
     for METHOD.

     Example:
          (tramp-set-completion-function "ssh"
           '((tramp-parse-sconfig "/etc/ssh_config")
             (tramp-parse-sconfig "~/.ssh/config")))
          
               => ((tramp-parse-sconfig "/etc/ssh_config")
                   (tramp-parse-sconfig "~/.ssh/config"))

   The following predefined functions parsing configuration files exist:

`tramp-parse-rhosts'
     This function parses files which are syntactical equivalent to
     `~/.rhosts'.  It returns both host names and user names, if
     specified.

`tramp-parse-shosts'
     This function parses files which are syntactical equivalent to
     `~/.ssh/known_hosts'.  Since there are no user names specified in
     such files, it can return host names only.

`tramp-parse-sconfig'
     This function returns the host nicknames defined by `Host' entries
     in `~/.ssh/config' style files.

`tramp-parse-hosts'
     A function dedicated to `/etc/hosts' style files.  It returns host
     names only.

`tramp-parse-passwd'
     A function which parses `/etc/passwd' like files.  Obviously, it
     can return user names only.

`tramp-parse-netrc'
     Finally, a function which parses `~/.netrc' like files.

   If you want to keep your own data in a file, with your own structure,
you might provide such a function as well.  This function must meet the
following conventions:

 - Function: my-tramp-parse file
     FILE must be either a file name on your host, or `nil'. The
     function must return a list of (USER HOST), which are taken as
     candidates for user and host name completion.

     Example:
          (my-tramp-parse "~/.my-tramp-hosts")
          
               => ((nil "toto") ("daniel" "melancholia"))


File: tramp.info,  Node: Remote Programs,  Next: Remote shell setup,  Prev: Customizing Completion,  Up: Configuration

How TRAMP finds and uses programs on the remote machine.
========================================================

TRAMP depends on a number of programs on the remote host in order to
function, including `ls', `test', `find' and `cat'.

   In addition to these required tools, there are various tools that
may be required based on the connection method. See *Note Inline
methods:: and *Note External transfer methods:: for details on these.

   Certain other tools, such as `perl' (or `perl5') and `grep' will be
used if they can be found. When they are available, they are used to
improve the performance and accuracy of remote file access.

   When TRAMP connects to the remote machine, it searches for the
programs that it can use. The variable TRAMP-REMOTE-PATH controls the
directories searched on the remote machine.

   By default, this is set to a reasonable set of defaults for most
machines. It is possible, however, that your local (or remote ;) system
administrator has put the tools you want in some obscure local
directory.

   In this case, you can still use them with TRAMP. You simply need to
add code to your `.emacs' to add the directory to the remote path.
This will then be searched by TRAMP when you connect and the software
found.

   To add a directory to the remote search path, you could use code such
as:

     ;; We load TRAMP to define the variable.
     (require 'tramp)
     ;; We have `perl' in "/usr/local/perl/bin"
     (add-to-list 'tramp-remote-path "/usr/local/perl/bin")


File: tramp.info,  Node: Remote shell setup,  Next: Windows setup hints,  Prev: Remote Programs,  Up: Configuration

Remote shell setup hints
========================

As explained in the *Note Overview:: section, TRAMP connects to the
remote host and talks to the shell it finds there.  Of course, when you
log in, the shell executes its init files.  Suppose your init file
requires you to enter the birth date of your mother; clearly TRAMP does
not know this and hence fails to log you in to that host.

   There are different possible strategies for pursuing this problem.
One strategy is to enable TRAMP to deal with all possible situations.
This is a losing battle, since it is not possible to deal with _all_
situations.  The other strategy is to require you to set up the remote
host such that it behaves like TRAMP expect.  This might be
inconvenient because you have to invest a lot of effort into shell
setup before you can begin to use TRAMP.

   The package, therefore, pursues a combined approach.  It tries to
figure out some of the more common setups, and only requires you to
avoid really exotic stuff.  For example, it looks through a list of
directories to find some programs on the remote host.  And also, it
knows that it is not obvious how to check whether a file exists, and
therefore it tries different possibilities.  (On some hosts and shells,
the command `test -e' does the trick, on some hosts the shell builtin
doesn't work but the program `/usr/bin/test -e' or `/bin/test -e'
works.  And on still other hosts, `ls -d' is the right way to do this.)

   Below you find a discussion of a few things that TRAMP does not deal
with, and that you therefore have to set up correctly.

SHELL-PROMPT-PATTERN
     After logging in to the remote host, TRAMP has to wait for the
     remote shell startup to finish before it can send commands to the
     remote shell.  The strategy here is to wait for the shell prompt.
     In order to recognize the shell prompt, the variable
     `shell-prompt-pattern' has to be set correctly to recognize the
     shell prompt on the remote host.

     Note that TRAMP requires the match for `shell-prompt-pattern' to
     be at the end of the buffer.  Many people have something like the
     following as the value for the variable: `"^[^>$][>$] *"'.  Now
     suppose your shell prompt is `a <b> c $ '.  In this case, TRAMP
     recognizes the `>' character as the end of the prompt, but it is
     not at the end of the buffer.

TRAMP-SHELL-PROMPT-PATTERN
     This regular expression is used by TRAMP in the same way as
     `shell-prompt-pattern', to match prompts from the remote shell.
     This second variable exists because the prompt from the remote
     shell might be different from the prompt from a local shell --
     after all, the whole point of TRAMP is to log in to remote hosts
     as a different user.  The default value of
     `tramp-shell-prompt-pattern' is the same as the default value of
     `shell-prompt-pattern', which is reported to work well in many
     circumstances.

`tset' and other questions
     Some people invoke the `tset' program from their shell startup
     scripts which asks the user about the terminal type of the shell.
     Maybe some shells ask other questions when they are started.  TRAMP
     does not know how to answer these questions.  There are two
     approaches for dealing with this problem.  One approach is to take
     care that the shell does not ask any questions when invoked from
     TRAMP.  You can do this by checking the `TERM' environment
     variable, it will be set to `dumb' when connecting.

     The variable `tramp-terminal-type' can be used to change this value
     to `dumb'.

     The other approach is to teach TRAMP about these questions.  See
     the variables `tramp-actions-before-shell' and
     `tramp-multi-actions' (for multi-hop connections).

Non-Bourne commands in `.profile'
     After logging in to the remote host, TRAMP issues the command
     `exec /bin/sh'.  (Actually, the command is slightly different.)
     When `/bin/sh' is executed, it reads some init files, such as
     `~/.shrc' or `~/.profile'.

     Now, some people have a login shell which is not `/bin/sh' but a
     Bourne-ish shell such as bash or ksh.  Some of these people might
     put their shell setup into the files `~/.shrc' or `~/.profile'.
     This way, it is possible for non-Bourne constructs to end up in
     those files.  Then, `exec /bin/sh' might cause the Bourne shell to
     barf on those constructs.

     As an example, imagine somebody putting `export FOO=bar' into the
     file `~/.profile'.  The standard Bourne shell does not understand
     this syntax and will emit a syntax error when it reaches this line.

     Another example is the tilde (`~') character, say when adding
     `~/bin' to `$PATH'.  Many Bourne shells will not expand this
     character, and since there is usually no directory whose name
     consists of the single character tilde, strange things will happen.

     What can you do about this?

     Well, one possibility is to make sure that everything in `~/.shrc'
     and `~/.profile' on all remote hosts is Bourne-compatible.  In the
     above example, instead of `export FOO=bar', you might use
     `FOO=bar; export FOO' instead.

     The other possibility is to put your non-Bourne shell setup into
     some other files.  For example, bash reads the file
     `~/.bash_profile' instead of `~/.profile', if the former exists.
     So bash aficionados just rename their `~/.profile' to
     `~/.bash_profile' on all remote hosts, and Bob's your uncle.

     The TRAMP developers would like to circumvent this problem, so if
     you have an idea about it, please tell us.  However, we are afraid
     it is not that simple: before saying `exec /bin/sh', TRAMP does
     not know which kind of shell it might be talking to.  It could be
     a Bourne-ish shell like ksh or bash, or it could be a csh
     derivative like tcsh, or it could be zsh, or even rc.  If the
     shell is Bourne-ish already, then it might be prudent to omit the
     `exec /bin/sh' step.  But how to find out if the shell is
     Bourne-ish?



File: tramp.info,  Node: Auto-save and Backup,  Prev: Windows setup hints,  Up: Configuration

Auto-save and Backup configuration
==================================

Explaining auto-save is still to do.

   Normally, Emacs writes backup files to the same directory as the
original files, but this behavior can be changed via the variable
`backup-directory-alist'.  In connection with TRAMP, this can have
unexpected side effects.  Suppose that you specify that all backups
should go to the directory `~/.emacs.d/backups/', and then you edit the
file `/su:root@localhost:/etc/secretfile'.  The effect is that the
backup file will be owned by you and not by root, thus possibly
enabling others to see it even if they were not intended to see it.

   When `backup-directory-alist' is nil (the default), such problems do
not occur.

   If you wish to customize the variable, the workaround is to include
special settings for Tramp files.  For example, the following statement
effectively `turns off' the effect of `backup-directory-alist' for
TRAMP files:

     (require 'tramp)
     (add-to-list 'backup-directory-alist
                  (cons tramp-file-name-regexp nil))


File: tramp.info,  Node: Windows setup hints,  Next: Auto-save and Backup,  Prev: Remote shell setup,  Up: Configuration

Issues with Cygwin ssh
======================

This section needs a lot of work!  Please help.

   If you use the Cygwin installation of ssh (you have to explicitly
select it in the installer), then it should work out of the box to just
select `sshx' as the connection method.  You can find information about
setting up Cygwin in their FAQ at `http://cygwin.com/faq/'.

   If you wish to use the `scpx' connection method, then you might have
the problem that Emacs calls `scp' with a Windows filename such as
`c:/foo'.  The Cygwin version of `scp' does not know about Windows
filenames and interprets this as a remote filename on the host `c'.

   One possible workaround is to write a wrapper script for `scp' which
converts the Windows filename to a Cygwinized filename.

   I guess that another workaround is to run Emacs under Cygwin, or to
run a Cygwinized Emacs.

   If you want to use either `ssh' based method on Windows, then you
might encounter problems with `ssh-agent'.  Using this program, you can
avoid typing the pass-phrase every time you log in (and the `scpx'
method more or less requires you to use `ssh-agent' because it does not
allow you to type a password or pass-phrase).  However, if you start
Emacs from a desktop shortcut, then the environment variable
`SSH_AUTH_SOCK' is not set and so Emacs and thus TRAMP and thus `ssh'
and `scp' started from TRAMP cannot communicate with `ssh-agent'.  It
works better to start Emacs from the shell.

   If anyone knows how to start `ssh-agent' under Windows in such a way
that desktop shortcuts can profit, please holler.  I don't really know
anything at all about Windows...


File: tramp.info,  Node: Usage,  Next: Bug Reports,  Prev: Configuration,  Up: Top

Using TRAMP
***********

Once you have installed TRAMP it will operate fairly transparently. You
will be able to access files on any remote machine that you can log in
to as though they were local.

   Files are specified to TRAMP using a formalized syntax specifying the
details of the system to connect to.  This is similar to the syntax used
by the Ange-FTP package.

   Something that might happen which surprises you is that Emacs
remembers all your keystrokes, so if you see a password prompt from
Emacs, say, and hit `<RET>' twice instead of once, then the second
keystroke will be processed by Emacs after TRAMP has done its thing.
Why, this type-ahead is normal behavior, you say.  Right you are, but
be aware that opening a remote file might take quite a while, maybe
half a minute when a connection needs to be opened.  Maybe after half a
minute you have already forgotten that you hit that key!

* Menu:

* Filename Syntax::             TRAMP filename conventions.
* Multi-hop filename syntax::   Multi-hop filename conventions.
* Filename completion::         Filename completion.
* Dired::                       Dired.


File: tramp.info,  Node: Filename Syntax,  Next: Multi-hop filename syntax,  Up: Usage

TRAMP filename conventions
==========================

To access the file LOCALNAME on the remote machine MACHINE you would
specify the filename `/MACHINE:LOCALNAME'.  This will connect to
MACHINE and transfer the file using the default method.  *Note Default
Method::.

   Some examples of TRAMP filenames are shown below.

`/melancholia:.emacs'
     Edit the file `.emacs' in your home directory on the machine
     `melancholia'.

`/melancholia.danann.net:.emacs'
     This edits the same file, using the fully qualified domain name of
     the machine.

`/melancholia:~/.emacs'
     This also edits the same file -- the `~' is expanded to your home
     directory on the remote machine, just like it is locally.

`/melancholia:~daniel/.emacs'
     This edits the file `.emacs' in the home directory of the user
     `daniel' on the machine `melancholia'. The `~<user>' construct is
     expanded to the home directory of that user on the remote machine.

`/melancholia:/etc/squid.conf'
     This edits the file `/etc/squid.conf' on the machine `melancholia'.


   Unless you specify a different name to use, TRAMP will use the
current local user name as the remote user name to log in with. If you
need to log in as a different user, you can specify the user name as
part of the filename.

   To log in to the remote machine as a specific user, you use the
syntax `/USER@MACHINE:/PATH/TO.FILE'.  That means that connecting to
`melancholia' as `daniel' and editing `.emacs' in your home directory
you would specify `/daniel@melancholia:.emacs'.

   It is also possible to specify other file transfer methods (*note
Default Method::) as part of the filename.  This is done by putting the
method before the user and host name, as in
`/METHOD:' (Note the trailing colon).  The user, machine and file
specification remain the same.

   So, to connect to the machine `melancholia' as `daniel', using the
`su' method to transfer files, and edit `.emacs' in my home directory I
would specify the filename `/su:daniel@melancholia:.emacs'.


File: tramp.info,  Node: Multi-hop filename syntax,  Next: Filename completion,  Prev: Filename Syntax,  Up: Usage

Multi-hop filename conventions
==============================

The syntax of multi-hop file names is necessarily slightly different
than the syntax of other TRAMP file names.  Here's an example multi-hop
file name, first in Emacs syntax and then in XEmacs syntax:

     /multi:rsh:out@gate:telnet:kai@real.host:/path/to.file

   This is quite a mouthful.  So let's go through it step by step.  The
file name consists of three parts.  The parts are separated by colons
The first part is `/multi', the method specification.  The second part
is `rsh:out@gate:telnet:kai@real.host' and specifies the hops.  The
final part is `/path/to.file' and specifies the file name on the remote
host.

   The first part and the final part should be clear.  See *Note
Multi-hop Methods::, for a list of alternatives for the method
specification.

   The second part can be subdivided again into components, so-called
hops.  In the above file name, there are two hops,
`rsh:out@gate' and `telnet:kai@real.host'.

   Each hop can _again_ be subdivided into (three) components, the "hop
method", the "user name" and the "host name".  The meaning of the
second and third component should be clear, and the hop method says
what program to use to perform that hop.

   The first hop, `rsh:out@gate', says to use `rsh' to log in as user
`out' to the host `gate'.  Starting at that host, the second hop,
`telnet:kai@real.host', says to use `telnet' to log in as user `kai' to
host `real.host'.

   *Note Multi-hop Methods::, for a list of possible hop method values.
The variable `tramp-multi-connection-function-alist' contains the list
of possible hop methods and information on how to execute them, should
you want to add your own.


File: tramp.info,  Node: Filename completion,  Next: Dired,  Prev: Multi-hop filename syntax,  Up: Usage

Filename completion
===================

Filename completion works with TRAMP for both completing methods, user
names and machine names (except multi hop methods) as well as for files
on remote machines.

   If you, for example, type `C-x C-f /t <TAB>', TRAMP might give you
as result the choice for

     telnet:				   tmp/
     toto:

   `telnet:' is a possible completion for the respective method, `tmp/'
stands for the directory `/tmp' on your local machine, and
`toto:' might be a host TRAMP has detected in your `~/.ssh/known_hosts'
file (given you're using default method `ssh').

   If you go on to type `e <TAB>', the minibuffer is completed to
`/telnet:'.  Next `<TAB>' brings you all machine names TRAMP detects in
your `/etc/hosts' file, let's say

     telnet:127.0.0.1:		   telnet:192.168.0.1:
     telnet:localhost:		   telnet:melancholia.danann.net:
     telnet:melancholia:

   Now you can choose the desired machine, and you can continue to
complete file names on that machine.

   As filename completion needs to fetch the listing of files from the
remote machine, this feature is sometimes fairly slow.  As TRAMP does
not yet cache the results of directory listing, there is no gain in
performance the second time you complete filenames.

   If the configuration files (*note Customizing Completion::), which
TRAMP uses for analysis of completion, offer user names, those user
names will be taken into account as well.


File: tramp.info,  Node: Dired,  Prev: Filename completion,  Up: Usage

Dired
=====

TRAMP works transparently with dired, enabling you to use this powerful
file management tool to manage files on any machine you have access to
over the Internet.

   If you need to browse a directory tree, Dired is a better choice, at
present, than filename completion.  Dired has its own cache mechanism
and will only fetch the directory listing once.


File: tramp.info,  Node: Bug Reports,  Next: Frequently Asked Questions,  Prev: Usage,  Up: Top

Reporting Bugs and Problems
***************************

Bugs and problems with TRAMP are actively worked on by the development
team. Feature requests and suggestions are also more than welcome.

   The TRAMP mailing list is a great place to get information on working
with TRAMP, solving problems and general discussion and advice on topics
relating to the package.

   The  mailing list is at <tramp-devel@mail.freesoftware.fsf.org>.
Messages sent to this address go to all the subscribers. This is _not_
the address to send subscription requests to.

   For help on subscribing to the list, send mail to the administrative
address, <tramp-devel-request@mail.freesoftware.fsf.org>, with the
subject `help'.

   To report a bug in TRAMP, you should execute `M-x tramp-bug'. This
will automatically generate a buffer with the details of your system and
TRAMP version.

   When submitting a bug report, please try to describe in excruciating
detail the steps required to reproduce the problem, the setup of the
remote machine and any special conditions that exist.

   If you can identify a minimal test case that reproduces the problem,
include that with your bug report. This will make it much easier for the
development team to analyze and correct the problem.


File: tramp.info,  Node: Frequently Asked Questions,  Next: Concept Index,  Prev: Bug Reports,  Up: Top

Frequently Asked Questions
**************************

   * Where can I get the latest TRAMP?

     TRAMP is available under the URL below.

     `http://savannah.nongnu.org/download/tramp/'

     There is also a Savannah project page.

     `https://savannah.gnu.org/projects/tramp/'

   * Which systems does it work on?

     The package has been used successfully on Emacs 20 and Emacs 21,
     as well as XEmacs 21.  XEmacs 20 is more problematic, see the
     notes in `tramp.el'.  I don't think anybody has really tried it on
     Emacs 19.

     The package was intended to work on Unix, and it really expects a
     Unix-like system on the remote end, but some people seemed to have
     some success getting it to work on NT Emacs.

     There is some informations on TRAMP on NT at the following URL;
     many thanks to Joe Stoy for providing the information:
     `ftp://ftp.comlab.ox.ac.uk/tmp/Joe.Stoy/'

     The above mostly contains patches to old ssh versions; Tom Roche
     has a Web page with instructions:
     `http://www4.ncsu.edu/~tlroche/plinkTramp.html'

     ??? Is the XEmacs info correct?

     ??? Can somebody provide some information for getting it to work
     on NT Emacs?  I think there was some issue with `ssh'?

   * I can't stop Ange-FTP starting with Emacs

     Ange-FTP is loaded from TRAMP automatically if you require a file
     by the ftp method.  Unfortunately, there are some Lisp packages
     which make Ange-FTP file name handlers active.  You can see it
     applying `C-h v file-name-handler-alist':

          file-name-handler-alist's value is
          (("^/[^/:]*\\'" . ange-ftp-completion-hook-function)
           ("^/[^/:]*[^/:.]:" . ange-ftp-hook-function)
           ("^/[^/]*$" . tramp-completion-file-name-handler)
           ("\\`/[^/:]+:" . tramp-file-name-handler)
           ("\\`/:" . file-name-non-special))

     Please try to find out which package is responsible for loading
     Ange-FTP, and raise a bug report.

     A workaround is to require Ange-FTP before TRAMP in your
     `~/.emacs', because TRAMP cleans up the entries in
     `file-name-handler-alist':

          ;; Ange-FTP temporarily required
          (require 'ange-ftp)
          ;; TRAMP cleans up `file-name-handler-alist'
          (require 'tramp)

   * File name completion does not work with TRAMP

     When you log in to the remote machine, do you see the output of
     `ls' in color? If so, this may be the cause of your problems.

     `ls' outputs ANSI escape sequences that your terminal emulator
     interprets to set the colors.  These escape sequences will confuse
     TRAMP however.

     In your `.bashrc', `.profile' or equivalent on the remote machine
     you probably have an alias configured that adds the option
     `--color=yes' or `--color=auto'.

     You should remove that alias and ensure that a new login _does not_
     display the output of `ls' in color.  If you still cannot use
     filename completion, report a bug to the TRAMP developers.

   * File name completion does not work in large directories

     TRAMP uses globbing for some operations.  (Globbing means to use
     the shell to expand wildcards such as `*.c'.)  This might create
     long command lines, especially in directories with many files.
     Some shells choke on long command lines, or don't cope well with
     the globbing itself.

     If you have a large directory on the remote end, you may wish to
     execute a command like `ls -d * ..?* > /dev/null' and see if it
     hangs.  Note that you must first start the right shell, which
     might be `/bin/sh', `ksh' or `bash', depending on which of those
     supports tilde expansion.

   * What kinds of systems does TRAMP work on

     TRAMP really expects the remote system to be a Unix-like system.
     The local system should preferably be Unix-like, as well, but
     TRAMP might work on NT with some tweaking.

   * How can I get notified when TRAMP file transfers are complete?

     The following snippet can be put in your `~/.emacs' file.  It makes
     Emacs beep after reading from or writing to the remote host.

          (defadvice tramp-handle-write-region
            (after tramp-write-beep-advice activate)
           " make tramp beep after writing a file."
           (interactive)
           (beep))
          (defadvice tramp-handle-do-copy-or-rename-file
            (after tramp-copy-beep-advice activate)
           " make tramp beep after copying a file."
           (interactive)
           (beep))
          (defadvice tramp-handle-insert-file-contents
            (after tramp-copy-beep-advice activate)
           " make tramp beep after copying a file."
           (interactive)
           (beep))

   * There's this `~/.sh_history' file on the remote host which keeps
     growing and growing.  What's that?

     Sometimes, TRAMP starts `ksh' on the remote host for tilde
     expansion.  Maybe `ksh' saves the history by default.  TRAMP tries
     to turn off saving the history, but maybe you have to help.  For
     example, you could put this in your `.kshrc':

          if [ -f $HOME/.sh_history ] ; then
             /bin/rm $HOME/.sh_history
          fi
          if [ "${HISTFILE-unset}" != "unset" ] ; then
             unset HISTFILE
          fi
          if [ "${HISTSIZE-unset}" != "unset" ] ; then
             unset HISTSIZE
          fi

   * TRAMP doesn't transfer strings with more than 500 characters
     correctly

     On some few systems, the implementation of `process-send-string'
     seems to be broken for longer strings.  This case, you should
     customize the variable `tramp-chunksize' to 500.  For a
     description how to determine whether this is necessary see the
     documentation of `tramp-chunksize'.



File: tramp.info,  Node: Version Control,  Next: Files directories and localnames,  Prev: Concept Index,  Up: Top

The inner workings of remote version control
********************************************

Unlike Ange-FTP, TRAMP has full shell access to the remote machine.
This makes it possible to provide version control for files accessed
under TRAMP.

   The actual version control binaries must be installed on the remote
machine, accessible in the directories specified in TRAMP-REMOTE-PATH.

   This transparent integration with the version control systems is one
of the most valuable features provided by TRAMP, but it is far from
perfect.  Work is ongoing to improve the transparency of the system.

* Menu:

* Version Controlled Files::    Determining if a file is under version control.
* Remote Commands::             Executing the version control commands on the remote machine.
* Changed workfiles::           Detecting if the working file has changed.
* Checking out files::          Bringing the workfile out of the repository.
* Miscellaneous Version Control::  Things related to Version Control that don't fit elsewhere.


File: tramp.info,  Node: Version Controlled Files,  Next: Remote Commands,  Up: Version Control

Determining if a file is under version control
==============================================

The VC package uses the existence of on-disk revision control master
files to determine if a given file is under revision control. These file
tests happen on the remote machine through the standard TRAMP
mechanisms.


File: tramp.info,  Node: Remote Commands,  Next: Changed workfiles,  Prev: Version Controlled Files,  Up: Version Control

Executing the version control commands on the remote machine
============================================================

There are no hooks provided by VC to allow intercepting of the version
control command execution. The calls occur through the `call-process'
mechanism, a function that is somewhat more efficient than the
`shell-command' function but that does not provide hooks for remote
execution of commands.

   To work around this, the functions `vc-do-command' and
`vc-simple-command' have been advised to intercept requests for
operations on files accessed via TRAMP.

   In the case of a remote file, the `shell-command' interface is used,
with some wrapper code, to provide the same functionality on the remote
machine as would be seen on the local machine.


File: tramp.info,  Node: Changed workfiles,  Next: Checking out files,  Prev: Remote Commands,  Up: Version Control

Detecting if the working file has changed
=========================================

As there is currently no way to get access to the mtime of a file on a
remote machine in a portable way, the `vc-workfile-unchanged-p'
function is advised to call an TRAMP specific function for remote files.

   The `tramp-vc-workfile-unchanged-p' function uses the functioning VC
diff functionality to determine if any changes have occurred between the
workfile and the version control master.

   This requires that a shell command be executed remotely, a process
that is notably heavier-weight than the mtime comparison used for local
files. Unfortunately, unless a portable solution to the issue is found,
this will remain the cost of remote version control.


File: tramp.info,  Node: Checking out files,  Next: Miscellaneous Version Control,  Prev: Changed workfiles,  Up: Version Control

Bringing the workfile out of the repository
===========================================

VC will, by default, check for remote files and refuse to act on them
when checking out files from the repository. To work around this
problem, the function `vc-checkout' knows about TRAMP files and allows
version control to occur.


File: tramp.info,  Node: Miscellaneous Version Control,  Prev: Checking out files,  Up: Version Control

Things related to Version Control that don't fit elsewhere
==========================================================

Minor implementation details, &c.

* Menu:

* Remote File Ownership::       How VC determines who owns a workfile.
* Back-end Versions::           How VC determines what release your RCS is.


File: tramp.info,  Node: Remote File Ownership,  Next: Back-end Versions,  Up: Miscellaneous Version Control

How VC determines who owns a workfile
-------------------------------------

Emacs provides the `user-full-name' function to return the login name
of the current user as well as mapping from arbitrary user id values
back to login names. The VC code uses this functionality to map from the
uid of the owner of a workfile to the login name in some circumstances.

   This will not, for obvious reasons, work if the remote system has a
different set of logins. As such, it is necessary to delegate to the
remote machine the job of determining the login name associated with a
uid.

   Unfortunately, with the profusion of distributed management systems
such as `NIS', `NIS+' and `NetInfo', there is no simple, reliable and
portable method for performing this mapping.

   Thankfully, the only place in the VC code that depends on the
mapping of a uid to a login name is the `vc-file-owner' function. This
returns the login of the owner of the file as a string.

   This function has been advised to use the output of `ls' on the
remote machine to determine the login name, delegating the problem of
mapping the uid to the login to the remote system which should know more
about it than I do.


File: tramp.info,  Node: Back-end Versions,  Prev: Remote File Ownership,  Up: Miscellaneous Version Control

How VC determines what release your RCS is
------------------------------------------

VC needs to know what release your revision control binaries you are
running as not all features VC supports are available with older
versions of `rcs(1)', `cvs(1)' or `sccs(1)'.

   The default implementation of VC determines this value the first
time it is needed and then stores the value globally to avoid the
overhead of executing a process and parsing its output each time the
information is needed.

   Unfortunately, life is not quite so easy when remote version control
comes into the picture. Each remote machine may have a different version
of the version control tools and, while this is painful, we need to
ensure that unavailable features are not used remotely.

   To resolve this issue, TRAMP currently takes the sledgehammer
approach of making the release values of the revision control tools
local to each TRAMP buffer, forcing VC to determine these values again
each time a new file is visited.

   This has, quite obviously, some performance implications. Thankfully,
most of the common operations performed by VC do not actually require
that the remote version be known. This makes the problem far less
apparent.

   Eventually these values will be captured by TRAMP on a system by
system basis and the results cached to improve performance.


File: tramp.info,  Node: Files directories and localnames,  Next: Issues,  Prev: Version Control,  Up: Top

How file names, directories and localnames are mangled and managed.
*******************************************************************

* Menu:

* Localname deconstruction::    Breaking a localname into its components.


File: tramp.info,  Node: Localname deconstruction,  Up: Files directories and localnames

Breaking a localname into its components.
=========================================

TRAMP file names are somewhat different, obviously, to ordinary file
names. As such, the lisp functions `file-name-directory' and
`file-name-nondirectory' are overridden within the TRAMP package.

   Their replacements are reasonably simplistic in their approach. They
dissect the filename, call the original handler on the localname and
then rebuild the TRAMP file name with the result.

   This allows the platform specific hacks in the original handlers to
take effect while preserving the TRAMP file name information.


File: tramp.info,  Node: Issues,  Prev: Files directories and localnames,  Up: Top

Debatable Issues and What Was Decided
*************************************

   * The uuencode method does not always work.

     Due to the design of TRAMP, the encoding and decoding programs
     need to read from stdin and write to stdout.  On some systems,
     `uudecode -o -' will read stdin and write the decoded file to
     stdout, on other systems `uudecode -p' does the same thing.  But
     some systems have uudecode implementations which cannot do this at
     all--it is not possible to call these uudecode implementations
     with suitable parameters so that they write to stdout.

     Of course, this could be circumvented: the `begin foo 644' line
     could be rewritten to put in some temporary file name, then
     `uudecode' could be called, then the temp file could be printed and
     deleted.

     But I have decided that this is too fragile to reliably work, so
     on some systems you'll have to do without the uuencode methods.

   * TRAMP does not work on XEmacs 20.

     This is because it requires the macro `with-timeout' which does not
     appear to exist in XEmacs 20.  I'm somewhat reluctant to add an
     emulation macro to TRAMP, but if somebody who uses XEmacs 20 steps
     forward and wishes to implement and test it, please contact me or
     the mailing list.

   * The TRAMP filename syntax differs between Emacs and XEmacs.

     The Emacs maintainers wish to use a unified filename syntax for
     Ange-FTP and TRAMP so that users don't have to learn a new syntax.
     It is sufficient to learn some extensions to the old syntax.

     For the XEmacs maintainers, the problems caused from using a
     unified filename syntax are greater than the gains.  The XEmacs
     package system uses EFS for downloading new packages.  So,
     obviously, EFS has to be installed from the start.  If the
     filenames were unified, TRAMP would have to be installed from the
     start, too.



File: tramp.info,  Node: Concept Index,  Next: Version Control,  Prev: Frequently Asked Questions,  Up: Top

Concept Index
*************

* Menu:

* .login file:                           Remote shell setup.
* .profile file:                         Remote shell setup.
* auto-save:                             Auto-save and Backup.
* backup:                                Auto-save and Backup.
* base-64 encoding:                      Inline methods.
* behind the scenes:                     Overview.
* bug reports:                           Bug Reports.
* configuration:                         Configuration.
* connection types, overview:            Connection types.
* create your own methods:               Customizing Methods.
* customizing completion:                Customizing Completion.
* customizing methods:                   Customizing Methods.
* Cygwin (with scpx method):             External transfer methods.
* Cygwin (with sshx method):             Inline methods.
* Cygwin and ssh-agent:                  Windows setup hints.
* Cygwin, issues:                        Windows setup hints.
* default configuration:                 Configuration.
* default method:                        Default Method.
* details of operation:                  Overview.
* development history:                   History.
* dired:                                 Dired.
* external methods:                      Connection types.
* external transfer methods <1>:         External transfer methods.
* external transfer methods:             Connection types.
* FAQ:                                   Frequently Asked Questions.
* fcp (with fcp method):                 External transfer methods.
* fcp method:                            External transfer methods.
* filename completion:                   Filename completion.
* filename examples:                     Filename Syntax.
* filename syntax:                       Filename Syntax.
* filename syntax for multi-hop files:   Multi-hop filename syntax.
* frequently asked questions:            Frequently Asked Questions.
* fsh (with fcp method):                 External transfer methods.
* fsh method:                            External transfer methods.
* ftp method:                            External transfer methods.
* history:                               History.
* hop method rsh:                        Multi-hop Methods.
* hop method ssh:                        Multi-hop Methods.
* hop method su:                         Multi-hop Methods.
* hop method sudo:                       Multi-hop Methods.
* hop method telnet:                     Multi-hop Methods.
* how it works:                          Overview.
* inline methods <1>:                    Connection types.
* inline methods:                        Inline methods.
* Kerberos (with krlogin method):        Inline methods.
* km krlogin:                            Inline methods.
* method fcp:                            External transfer methods.
* method fsh:                            External transfer methods.
* method ftp:                            External transfer methods.
* method krlogin:                        Inline methods.
* method multi:                          Multi-hop Methods.
* method plink:                          Inline methods.
* method pscp:                           External transfer methods.
* method rcp:                            External transfer methods.
* method rsh:                            Inline methods.
* method rsync:                          External transfer methods.
* method scp:                            External transfer methods.
* method scpx:                           External transfer methods.
* method scpx with Cygwin:               Windows setup hints.
* method smb:                            External transfer methods.
* method ssh:                            Inline methods.
* method sshx:                           Inline methods.
* method sshx with Cygwin:               Windows setup hints.
* method su:                             Inline methods.
* method sudo:                           Inline methods.
* method telnet:                         Inline methods.
* methods, external transfer <1>:        Connection types.
* methods, external transfer:            External transfer methods.
* methods, inline <1>:                   Inline methods.
* methods, inline:                       Connection types.
* methods, multi-hop <1>:                Connection types.
* methods, multi-hop:                    Multi-hop Methods.
* methods, out-of-band <1>:              External transfer methods.
* methods, out-of-band:                  Connection types.
* mimencode:                             Inline methods.
* multi method:                          Multi-hop Methods.
* multi-hop filename syntax:             Multi-hop filename syntax.
* multi-hop methods <1>:                 Connection types.
* multi-hop methods:                     Multi-hop Methods.
* obtaining Tramp:                       Obtaining TRAMP.
* out-of-band methods <1>:               Connection types.
* out-of-band methods:                   External transfer methods.
* overview:                              Overview.
* plink (with pscp method):              External transfer methods.
* plink method:                          Inline methods.
* pscp (with pscp method):               External transfer methods.
* pscp method:                           External transfer methods.
* PuTTY (with pscp method):              External transfer methods.
* rcp (with rcp method):                 External transfer methods.
* rcp method:                            External transfer methods.
* remote shell setup:                    Remote shell setup.
* rsh (with rcp method):                 External transfer methods.
* rsh hop method:                        Multi-hop Methods.
* rsh method:                            Inline methods.
* rsync (with rsync method):             External transfer methods.
* rsync method:                          External transfer methods.
* scp (with scp method):                 External transfer methods.
* scp (with scpx method):                External transfer methods.
* scp method:                            External transfer methods.
* scpx method:                           External transfer methods.
* scpx method with Cygwin:               Windows setup hints.
* selecting config files:                Customizing Completion.
* shell init files:                      Remote shell setup.
* smb method:                            External transfer methods.
* ssh (with rsync method):               External transfer methods.
* ssh (with scp method):                 External transfer methods.
* ssh (with scpx method):                External transfer methods.
* ssh hop method:                        Multi-hop Methods.
* ssh method:                            Inline methods.
* ssh-agent:                             External transfer methods.
* SSH_AUTH_SOCK and Emacs on Windows:    Windows setup hints.
* sshx method:                           Inline methods.
* sshx method with Cygwin:               Windows setup hints.
* su hop method:                         Multi-hop Methods.
* su method:                             Inline methods.
* sudo hop method:                       Multi-hop Methods.
* sudo method:                           Inline methods.
* telnet hop method:                     Multi-hop Methods.
* telnet method:                         Inline methods.
* tset Unix command:                     Remote shell setup.
* type-ahead:                            Usage.
* Unix command tset:                     Remote shell setup.
* using non-standard methods:            Customizing Methods.
* using TRAMP:                           Usage.
* uuencode:                              Inline methods.
* Version Control:                       Version Control.



Tag Table:
Node: Top1343
Node: Overview5930
Ref: Overview-Footnote-112112
Node: Obtaining TRAMP12264
Node: History13984
Node: Configuration14706
Node: Connection types16339
Node: Inline methods18511
Node: External transfer methods23621
Ref: External transfer methods-Footnote-131297
Node: Multi-hop Methods31376
Node: Default Method34310
Node: Customizing Methods36529
Node: Customizing Completion36936
Node: Remote Programs39904
Node: Remote shell setup41536
Node: Auto-save and Backup47747
Node: Windows setup hints48920
Node: Usage50686
Node: Filename Syntax51906
Node: Multi-hop filename syntax54031
Node: Filename completion55860
Node: Dired57409
Node: Bug Reports57850
Node: Frequently Asked Questions59213
Node: Version Control65117
Node: Version Controlled Files66260
Node: Remote Commands66671
Node: Changed workfiles67570
Node: Checking out files68438
Node: Miscellaneous Version Control68893
Node: Remote File Ownership69311
Node: Back-end Versions70613
Node: Files directories and localnames72076
Node: Localname deconstruction72407
Node: Issues73107
Node: Concept Index75130

End Tag Table
