DESCRIPTION

Programmable Completion

First, the command name is identified. If a compspec has been defined for that command, the compspec is used to generate the list of possible completions for the word. If the command word is a full pathname, a compspec for the full pathname is searched for first. If no compspec is found for the full pathname, an attempt is made to find a compspec for the portion following the final slash.

Once a compspec has been found, it is used to generate the list of matching words. If a compspec is not found, the default Psh completion described above (Where is it described?) is performed.

First, the actions specified by the compspec are used. Only matches which are prefixed by the word being completed are returned. When the -f or -d option is used for filename or directory name completion, the shell variable FIGNORE is used to filter the matches. See "ENVIRONMENT VARIABLES" for a description of FIGNORE.

Any completions specified by a filename expansion pattern to the -G option are generated next. The words generated by the pattern need not match the word being completed. The GLOBIGNORE shell variable is not used to filter the matches, but the FIGNORE shell variable is used.

Next, the string specified as the argument to the -W option is considered. The string is first split using the characters in the IFS special variable as delimiters. Shell quoting is honored. Each word is then expanded using brace expansion, tilde expansion, parameter and variable expansion, command substitution, arithmetic expansion, and pathname expansion, as described above (Where is it described?). The results are split using the rules described above (Where is it described?). No filtering against the word being completed is performed.

After these matches have been generated, any shell function or command specified with the -F and -C options is invoked. When the function or command is invoked, the first argument is the word being completed, the second argument is the current command line, the third argument is the index of the current cursor position relative to the beginning of the current command line, and the fourth argument is the name of the command whose arguments are being completed. If the current cursor position is at the end of the current command, the value of the third argument is equal to the length of the second argument string.

No filtering of the generated completions against the word being completed is performed; the function or command has complete freedom in generating the matches.

Any function specified with -F is invoked first. The function may use any of the shell facilities, including the compgen builtin described below (See "Programmable Completion Builtins".), to generate the matches. It returns a array including the possible completions. For example;

        sub _foo_func {
            my ($cur, $line, $start, $cmd) = @_;
            ...
            return @possible_completions;
        }
        complete -F _foo_func bar

Next, any command specified with the -C option is invoked in an environment equivalent to command substitution. It should print a list of completions, one per line, to the standard output. Backslash may be used to escape a newline, if necessary.

After all of the possible completions are generated, any filter specified with the -X option is applied to the list. The filter is a pattern as used for pathname expansion; a "&" in the pattern is replaced with the text of the word being completed. A literal "&" may be escaped with a backslash; the backslash is removed before attempting a match. Any completion that matches the pattern will be removed from the list. A leading "!" negates the pattern; in this case any completion not matching the pattern will be removed.

Finally, any prefix and suffix specified with the -P and -S options are added to each member of the completion list, and the result is returned to the Readline completion code as the list of possible completions.

If a compspec is found, whatever it generates is returned to the completion code as the full set of possible completions. The default Bash completions are not attempted, and the Readline default of filename completion is disabled.

Programmable Completion Builtins

compgen

        compgen [OPTION] [WORD]
    

Generate possible completion matches for WORD according to the OPTIONs, which may be any option accepted by the complete builtin with the exception of -p and -r, and write the matches to the standard output. When using the -F or -C options, the various shell variables set by the programmable completion facilities, while available, will not have useful values.

The matches will be generated in the same way as if the programmable completion code had generated them directly from a completion specification with the same flags. If WORD is specified, only those completions matching WORD will be displayed.

The return value is true unless an invalid option is supplied, or no matches were generated.

complete

        complete [-abcdefjkvu] [-A ACTION] [-G GLOBPAT] [-W WORDLIST]
                 [-P PREFIX] [-S SUFFIX] [-X FILTERPAT] [-x FILTERPAT]
                 [-F FUNCTION] [-C COMMAND] NAME [NAME ...]
        complete -pr [NAME ...]
    

Specify how arguments to each NAME should be completed. If the -p option is supplied, or if no options are supplied, existing completion specifications are printed in a way that allows them to be reused as input. The -r option removes a completion specification for each NAME, or, if no NAMEs are supplied, all completion specifications.

The process of applying these completion specifications when word completion is attempted is described above (See Programmable Completion.).

Other options, if specified, have the following meanings. The arguments to the -G, -W, and -X options (and, if necessary, the -P and -S options) should be quoted to protect them from expansion before the complete builtin is invoked.

AUTHOR

SEE ALSO

EXAMPLES

        source complete-examples