4.11 Selecting config files for user/host name completion

tramp-completion-function-alist uses predefined files for user and host name completion (see File name completion). For each method, it keeps a set of configuration files and a function that can parse that file. Each entry in tramp-completion-function-alist is of the form (method pair1 pair2 …).

Each pair is composed of (function file). function is responsible for extracting 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-shostkeys

SSH2 parsing of directories /etc/ssh2/hostkeys/* and ~/ssh2/hostkeys/*. Hosts are coded in file names hostkey_portnumber_host-name.pub. User names are always nil.

tramp-parse-sknownhosts

Another SSH2 style parsing of directories like /etc/ssh2/knownhosts/* and ~/ssh2/knownhosts/*. This case, hosts names are coded in file names host-name.algorithm.pub. User names are always nil.

tramp-parse-hosts

A function dedicated to /etc/hosts for host names.

tramp-parse-passwd

A function which parses /etc/passwd files for user names.

tramp-parse-netrc

A function which parses ~/.netrc and ~/.authinfo-style files.

To keep a custom file with custom data in a custom structure, a custom function has to be provided. This function must meet the following conventions:

Function: my-tramp-parse file

file must be either a file on the host, or nil. The function must return a list of (user host), which are taken as candidates for completion for user and host names.

Example:

(my-tramp-parse "~/.my-tramp-hosts")

     ⇒ ((nil "toto") ("daniel" "melancholia"))