Mac でコマンドラインからボリュームをコントロールする

volume controle

#!/bin/bash
current=$(osascript -e "output volume of (get volume settings)")

if [ ${#@} -eq 0 ];then
  echo "current volume: $current"
  exit
fi

set=$current
num=10

function getnum {
  local digit=$(expr $1 : '[0-9]*')
  if [ $digit -gt 0 -a $digit -lt 4 ];then
    if [ $1 -lt 101 ];then
      num=$1
    fi
  else
    echo 'invalid argument';exit;
  fi
  echo $num
}

if [ $1 = 'up' ];then
  if [ ${#@} -gt 1 ];then
    num=$(getnum $2)
  fi
  set=$(expr $current + $num)
elif [ $1 = 'down' ];then
  if [ ${#@} -gt 1 ];then
    num=$(getnum $2)
  fi
  set=$(expr $current - $num)
elif [ $1 = 'mute' ];then
  set=0
elif [ $(expr $1 : '[0-9]*') ];then
  set=$1
else echo 'invalid argument';exit;
fi

osascript -e "set Volume output volume $set"
echo "set volume $set"