Check if Script is already running

# Check if Script is already running
pidof -o %PPID -x "$0" >/dev/null && echo "ERROR: Script $0 already running" && exit 1

# if the above doesn't work(if the version of pidof works differently)
# then try this  (I needed this for script on android with Termux)
pgrep -f "$0"| grep -v $$ > /dev/null && echo "ERROR: Script $0 already running" && exit 1