Bash – Configure autocomplete for the first argument, leave the others alone

autocompletebash

I have a utility that takes a load of different arguments. For now, I want to autocomplete the first argument, but leave all the others to fall through to normal autocompletion. How do I do that?

function _my_autocomplete_()
{
    case $COMP_CWORD in
        1) COMPREPLY=($(compgen -W "$(get_args_somehow)" -- ${COMP_WORDS[COMP_CWORD]}));;
        *) # What goes here?
    esac
}

complete -F _my_autocomplete_ mycommand

Best Answer

Apparently I completely missed your question. The answer is that there's no well-defined "normal autocompletion." However, if you know what sort of thing you'd like it to complete (files, aliases, pids, variable names, etc.), you can give one or more flags to compgen. See this compgen manual page, specifically the -A options under complete (they're the same). E.g. if you want to complete file names, you would use this:

compgen -f -- "${COMP_WORDS[COMP_CWORD]}"

If you want to complete commands (incl. aliases, functions, etc.), you can use this:

compgen -back -A function -- "${COMP_WORDS[COMP_CWORD]}"

Use $COMP_CWORD to get the index of the word being completed. If the index isn't 1, set $COMPREPLY to () and return.

COMP_CWORD

    An index into ${COMP_WORDS} of the word containing the current 
    cursor position. This variable is available only in shell functions
    invoked by the programmable completion facilities

Related Solutions

Add arguments from previous command to zsh completion

You can add your completer to the list of completers used by default:

zstyle ':completion:*' completer _last_command_args _complete

Bash – Custom autocomplete: deal with spaces in filenames

Believe it might be better to use compgen instead of find in this case.

You probably already have a completion script with system. Try e.g.

locate bash_completion

On Debian variants this is probably:

/usr/share/bash-completion/bash_completion

where you find e.g. _filedir. So the simplest way then would be something in the direction of:

*)
    pushd "/some/path" >/dev/null
    _filedir
    popd >/dev/null

If that is not an option this could be a starter:

_comp_by_path()
{
    local opt cur dir
    local IFS=$'\n' x tmp
    local -a tokens

    opt="$1"
    cur="$2"
    dir="$3"

    # Enter target directory
    pushd "$dir" >/dev/null

    # Get directories, filtered against current
    [[ "$opt" != "-f" ]] && \
    x=$( compgen -d -- "$cur" ) &&
    while read -r tmp; do
        tokens+=( "$tmp" )
    done <<< "$x"

    # Get files, filtered against current
    [[ "$opt" != "-d" ]] && \
    x=$( compgen -f -- "$cur" ) &&
    while read -r tmp; do
        tokens+=( "$tmp" )
    done <<< "$x"

    # If anything found
    if [[ ${#tokens[@]} -ne 0 ]]; then
        # Make sure escaping is OK
        compopt -o filenames 2>/dev/null
        COMPREPLY+=( "${tokens[@]}" )
    fi

    # Go back
    popd >/dev/null
}

_GetOptMyCommand()
{
    local cur

    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"

    case "$cur" in
    -*)
        COMPREPLY=( $( compgen -W "-h -l --help --list --" -- "$cur" ) );;
    *)
        _comp_by_path "any" "$cur" "/some/path"
    esac
}

complete -F _GetOptMyCommand my_command

A variant using find could be something in direction of this:

_zaso()
{
    local dir="$1"

    pushd "$dir" >/dev/null
    find * -maxdepth 0 2>/dev/null
    popd >/dev/null
}

_comp_with_find()
{
    local cur dir      
    local IFS=$'\n'

    cur="$1"
    dir="$2"

    compopt -o filenames 2>/dev/null
    COMPREPLY=( $( compgen -W "$(_zaso "$dir")" -- "$cur" ) );
}

Also note that printf in Bash has a %q option. So to generate quoted strings this is an option to play with:

find * -maxdepth 0 2>/dev/null && \
while read -r tmp; do
    printf "%q\n" "$tmp"
done <<< "$x"

Also not that file names can have newline characters in which a lot of this will break. Have not found a way to use \0 with compgen.

Best Answer

Related Solutions

Add arguments from previous command to zsh completion

Bash – Custom autocomplete: deal with spaces in filenames

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