eject.sh

#!/usr/bin/env bash
#
# single step iTunes external drive ejection

disk="/dev/disk2"
music_path=/Volumes/media/music

itunes_pid=$(pgrep "^itunes$")
itunes_status=$(lsof -p "$itunes_pid" | grep "$music_path")

# kill iTunes if has an open filehandle to external drive
if [[ -n "$itunes_status" ]]; then
    pkill -sighup "$itunes_pid"
fi

diskutil eject "$disk"