a.sh contains:
mkdir abc
I made it executable using:
chmod 777 a.sh
Then I configured crontab using:
crontab -e
And entered this line:
56 09 * * * /home/subir/Jarvis/a.sh
The abc directory is not created at that given time.
Which steps can I take to figure out why this does not work as expected?

/home/subir/Jarvis/a.shfrom an interactive shell?abcdirectory in your home directory though, is that not where you want it? If so create it elsewhere.cron.allowfile.