simple script for volume control with alsa

vol

#!/usr/bin/env bash
#             _
# __   _____ | |  a simple script to
# \ \ / / _ \| |  control volume from
#  \ V / (_) | |  the command-line or
#   \_/ \___/|_|  a keybinding
#
# Author: Nova Senco
# Last Change: 29 April 2021

VER='1.2'

printhelp(){
  cat <<DONE
Usage: $(basename $0) [OPTIONS]

 Easily see and change volume with amixer.

  Quick Examples:
   vol -i    # increase volume by 5 to nearest multiple of 5
   vol -ii   # increase volume by 10 to nearest multiple of 5
   vol -d    # decrease volume by 5 to nearest multiple of 5
   vol -t    # toggle mute
   vol -m    # mute
   vol -i 5  # increase volume by 5

OPTIONS:
 -i --increase [<amt>]  increment volume by <amt> (default: 5)
 -d --decrease [<amt>]  decrement volume by <amt> (default: 5)
 -s --set <amt>         set volume to <amt>
 -x --mixer <mixer>     select <mixer> (when unspecified: "Master")
 -m --mute              mute
 -u --unmute            unmute
 -t --toggle            toggle mute
 -q --quiet             don't print or notify; negates -v
 -v --verbose           print to stdout (-vv to debug) and don't notify
 -n --notify            notify (even if -v or -q passed); default if noninteractive
 -N --no-notify         do not notify (even if -n passed or noninteractive)

 -h --help              display this help and exit
 -V --version           display the version and exit
DONE
}

argv="$(getopt -n vol \
  -l 'help,version,quiet,verbose,notify,no-notify,increase::,decrease::,set:,mixer:,mute,unmute,toggle' \
  -o 'hVqvnNi::d::s:x:mut' -- "$@" \
  )"

[[ $? -ne 0 ]] && exit 1

eval set -- "$argv"

mixer='Master'
voldelta=0
volstddelta=0
volset=-1
mutectl=0
verbosity=0
toggle='-1'
tty -s && notify=0 || notify=1
nonotify=0

while true
do
  case "$1"
    in

    -h|--help)
    printhelp;
    exit 0
    ;;

  -V|--version)
    echo "vol $VER"
    exit 0
    ;;

  -i|--increase)
    if [[ $2 =~ ^[0-9]+$ ]]
    then
      ((voldelta+=$2))
    else
      ((volstddelta+=1))
    fi
    shift
    shift
    ;;

  -d|--decrease)
    if [[ $2 =~ ^[0-9]+$ ]]
    then
      ((voldelta-=$2))
    else
      ((volstddelta-=1))
    fi
    shift
    shift
    ;;

  -s|--set)
    if [[ ! $2 =~ ^[0-9]+$ ]]
    then
      if [[ $verbosity -ge 0 ]]
      then
        >&2 echo "vol: invalid option: '$1' requires integer, not '$2'"
      fi
      exit 2
    fi
    volset="$2"
    shift
    shift
    ;;

  -m|--mute)
    shift
    ((mutectl++))
    ;;

  -u|--unmute)
    shift
    ((mutectl--))
    ;;

  -t|--toggle)
    shift
    ((toggle*=-1))
    ;;

  -v|--verbose)
    shift
    ((verbosity++))
    ;;

  -q|--quiet)
    shift
    ((verbosity--))
    ;;

  -n|--notify)
    shift
    notify=1
    ;;

  -N|--no-notify)
    shoft
    nonotify=1
    ;;

  -x|--mixer)
    shift
    mixer="$1"
    shift
    ;;

  --)
    shift
    break
    ;;

  esac
done

read vol on_off < <(amixer get "$mixer" 2>/dev/null \
  | perl -n -e '/\[(\d+)%\].*\[(on|off)\]$/ && print("$1 $2\n") && exit')

if [[ -z $vol ]]
then
  >&2 echo "Fatal Error: unable to use amixer to get volume information with \"amixer get $mixer\"."
  exit 1
fi

if [[ $volstddelta -ne 0 ]]
then
  drift=$(( 2-((vol%5+2)%5) ))
  ((voldelta+=volstddelta*5+drift))
fi

if [[ $volset -ne -1 ]]
then
  [[ $verbosity -gt 1 ]] && >&2 echo "> volume = $volset"
  amixer set "$mixer" "$volset%" >/dev/null
fi

if [[ $voldelta -ne 0 ]]
then
  volsym='+'
  if [[ $voldelta -lt 0 ]]
  then
    volsym='-'
    ((voldelta*=-1))
  fi
  [[ $verbosity -gt 1 ]] && >&2 echo "> volume $volsym= $voldelta"
  amixer set "$mixer" "$voldelta%$volsym" >/dev/null
fi

if [[ $toggle -eq 1 ]]
then
  [[ $verbosity -gt 1 ]] && >&2 echo '> toggling mute'
  amixer set "$mixer" toggle >/dev/null
else
  if [[ $mutectl -gt 0 ]]
  then
    [[ $verbosity -gt 1 ]] && >&2 echo '> muting'
    amixer set "$mixer" mute >/dev/null
  elif [[ $mutectl -lt 0 ]]
  then
    [[ $verbosity -gt 1 ]] && >&2 echo '> unmuting'
    amixer set "$mixer" unmute >/dev/null
  fi
fi

read vol on_off < <(amixer get "$mixer" 2>/dev/null \
  | perl -n -e '/\[(\d+)%\].*\[(on|off)\]$/ && print("$1 $2\n") && exit')

mutestr=
if [[ $on_off == off ]]
then
  mutestr='muted'
fi

if [[ $verbosity -gt 0 ]]
then
  echo "$vol%${mutestr:+($mutestr)}"
fi

if [[ -n $mutestr ]] || [[ $vol -eq 0 ]]
then
  icon_name="audio-volume-muted"
elif [[ $vol -lt 33 ]]
then
  icon_name="audio-volume-low"
elif [[ $vol -lt 67 ]]
then
  icon_name="audio-volume-medium"
else
  icon_name="audio-volume-high"
fi

if [[ $notify -eq 1 && $nonotify -ne 1 ]]
then
  # pgrep -x dunst >/dev/null && \
  notify-send "${mutestr:-vol}" \
    -i "$icon_name" \
    -h "int:value:$vol" \
    -h string:synchronous:volume
fi