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

Someone please shoot me down if I'm wrong here

I understand that the mkdir operation is atomic, so you could create a lock directory

#!/bin/sh
lockdir=/tmp/AXgqg0lsoeykp9L9NZjIuaqvu7ANILL4foeqzpJcTs3YkwtiJ0
mkdir $lockdir  || {
    echo "lock directory exists. exiting"
    exit 1
}
# take pains to remove lock directory when script terminates
trap "rmdir $lockdir" EXIT INT KILL TERM

# rest of script here