/apps/test/script/test_script.sh: bad substitution Error while running script through Cron Job

I was getting the following error while running the shell script through Cron Job..

/apps/test/script/test_script.sh: bad substitution

I was using bash when running this script manually. But while scheduling this script in a cron job a different shell (K shell) was being used. I put the following as first line of my script and it worked fine:

Solution:

#!/bin/bash