How to check if another instance of my shell script is running

Question

GNU bash, version 1.14.7(1)

I have a script is called \"abc.sh\" I have to check this from abc.sh script only... inside it I have written f

Answer 1

This is compact and universal

# exit if another instance of this script is running
for pid in $(pidof -x `basename $0`); do
   [ $pid != $$ ] && { exit 1; }
done