Mini Shell

#!/bin/bash
# Copyright 2013 Red Hat, Inc.  All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

__contains_word() {
    local word="$1"
    shift
    for w in "$@"; do [[ $w == "$word" ]] && return 0; done
    return 1
}

_dracut() {
    local cur=${COMP_WORDS[COMP_CWORD]} prev=${COMP_WORDS[COMP_CWORD - 1]}
    local -A OPTS=(
        [STANDALONE]='-f -v -q -l -H -h -M -N
            --ro-mnt --force --kernel-only --no-kernel --strip --nostrip
            --hardlink --nohardlink --noprefix --mdadmconf --nomdadmconf
            --lvmconf --nolvmconf --debug --profile --verbose --quiet
            --local --hostonly --no-hostonly --fstab --help --bzip2 --lzma
            --xz --zstd --no-compress --gzip --list-modules --show-modules --keep
            --printsize --regenerate-all --noimageifnotneeded --early-microcode
            --no-early-microcode --print-cmdline --reproducible --uefi
            --enhanced-cpio --rebuild --aggresive-strip --hostonly-cmdline
            --no-hostonly-cmdline --no-hostonly-default-device --nofscks
            --hostonly-i18n --no-hostonly-i18n --lzo --lz4 --no-reproducible
            --no-uefi --no-machineid --version
            '
        [ARG]='-a -m -o -d -I -k -c -L -r -i
            --kver --add --force-add --add-drivers --force-drivers
            --omit-drivers --modules --omit --drivers --filesystems --install
            --fwdir --libdirs --fscks --add-fstab --mount --device
            --kmoddir --conf --confdir --tmpdir --stdlog --compress --prefix
            --kernel-cmdline --sshkey --persistent-policy --install-optional
            --loginstall --uefi-stub --kernel-image --squash-compressor
            --sysroot --hostonly-mode --hostonly-nics --include --logfile
            --uefi-splash-image --sbat
            '
    )

    # shellcheck disable=SC2086
    if __contains_word "$prev" ${OPTS[ARG]}; then
        case $prev in
            --kmoddir | -k | --fwdir | --confdir | --tmpdir | -r | --sysroot)
                comps=$(compgen -d -- "$cur")
                compopt -o filenames
                ;;
            -c | --conf | --sshkey | --add-fstab | --add-device | -I | \
                --install | --install-optional | --uefi-splash-image)
                comps=$(compgen -f -- "$cur")
                compopt -o filenames
                ;;
            -a | -m | -o | --add | --modules | --omit)
                comps=$(dracut --list-modules 2> /dev/null)
                ;;
            --persistent-policy)
                comps=$(
                    cd /dev/disk/ || return 0
                    printf -- "%s " *
                )
                ;;
            --kver)
                comps=$(
                    cd /lib/modules || return 0
                    echo [0-9]*
                )
                ;;
            --hostonly-mode)
                comps="sloppy strict"
                ;;
            --hostonly-nics)
                comps=$(
                    cd /sys/class/net/ || return 0
                    printf -- "%s " *
                )
                ;;
            *)
                return 0
                ;;
        esac
        # shellcheck disable=SC2207
        # shellcheck disable=SC2016
        COMPREPLY=($(compgen -W '$comps' -- "$cur"))
        return 0
    fi

    if [[ $cur == -* ]]; then
        # shellcheck disable=SC2207
        # shellcheck disable=SC2016
        COMPREPLY=($(compgen -W '${OPTS[*]}' -- "$cur"))
        return 0
    fi

    local args
    _count_args
    if [[ $args -eq 1 ]]; then
        _filedir
        return 0
    elif [[ $args -eq 2 ]]; then
        # shellcheck disable=SC2034
        comps=$(
            cd /lib/modules || return 0
            echo [0-9]*
        )
        # shellcheck disable=SC2207
        # shellcheck disable=SC2016
        COMPREPLY=($(compgen -W '$comps' -- "$cur"))
        return 0
    fi
}

complete -F _dracut dracut