Shell Programming and Scripting

I apologize if this question has been answered else where or is too elementary.

I ran across a KSH script (long unimportant story) that does this:

Code:

if [ blahblah ] ; then
   CAS_SRC_LOG="/var/log/cas_src.log 2>&1"
else
   CAS_SRC_LOG="/dev/null 2>&1"
fi

then does this:

Code:

    /usr/bin/echo "heartbeat: `/usr/bin/date` " >> $CAS_SRC_LOG

In other words, based on some condition, the standard output destination is set to a either a file or to null. That was the intent.

In actuality, instead of going to null, the output goes to a file /dev/"null 2>&1"

Code:

-rw-r--r--    1 root     system     76774847 Feb 13 17:07 null 2>&1

My question is, what are the substitution and command line parsing rules? Why didn't the built command line string get parsed as expected?





Thanks
John Morrison