mute programs on linux (pulseaudio)

#!/bin/bash
# List or toggle mute on pulseaudio clients by process name

main() {
    local action=toggle
    while getopts :l option; do
        case "$option" in
                l) list ; exit 0 ;;
            ?) usage 1 "invalid option: -$OPTARG" ;;
        esac
    done
    shift $((OPTIND - 1))

    local pid=$(pidof "$1")
    if [[ -z "$pid" ]]; then
        echo "error: no running processes for: $1" >&2
    elif [[ "$1" ]]; then
        toggle "$1"
    else
        echo "specify an application name"
          exit 1
    fi
}

list() {
    pacmd list-sink-inputs | gawk '
    $1 == "application.name" {name = $3}
    $1 == "application.process.binary" {bin = $3}
    $1 == "application.process.id" {id = $3}
    {
        if (name != "" && bin != "" && id != "")
            {
                gsub("\"","",name)
                gsub("\"","",bin)
                gsub("\"","",id)
                printf "%-20s %-20s %-20s \n", name, bin, id;
                bin = ""; id = ""; name = "";
           }
    }
    '
}

toggle() {
     local pids=$(pidof "$1")
     for pid in $pids; do
          local index=$(get_index $pid)
          [[ "$index" ]] && pactl set-sink-input-mute $index toggle
     done
}

get_index() {
     pacmd list-sink-inputs | \
     gawk -v pid=$1 '
     $1 == "index:" {idx = $2}
     $1 == "application.process.id" && $3 == "\"" pid "\"" {print idx; exit}
     '
}

main "$@"