UNIX for Dummies Questions & Answers

Hey out there. I have a .sh file I am calling from cron that I am trying to use to shut down the app at midnight. I have a file that does it and works just fine if I run it by typing "bash crontabstop.sh" from a command prompt. But if I call the file from a crontab I get this output.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/prod/app/iplax/current/IPWorkers/bin/crontabstop.sh: whoami: not found
IP Web App wasn't running.

Stop webapp complete.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
And the webapp never shuts down
This is the contents of the file. What do I need to do to get this to run when calling this file from crontab?

Code:

pid=`whoami`
if [ "$pid" != '' ] ; then
   cd ~ 
    stop
else
    echo "IP Web App wasn't running."
fi
echo " "
echo "Stop webapp complete."

Set PATH at top of script same as your current path in your sh shell.

That script looks suspect. Unless you have a bizzare PATH that includes the local directory, why bother CD-ing before running stop ?

I copied and pasted from a working script so short answer...dont know.

Never, ever blindly copy-paste code which you don't know how it works.

That looks like a badly-written script which only works in someone's home directory and depends on their own weird profile settings.

As posted and when run from the local directory, the entire script always executes:
The code never checks whether any process is running. The whoami command is a Shell Builtin which just replies with your current username.

Have you had any training in Shell Programming?