How to write perl substitute command in shell script without invoking a perl script file seperately.

for ex:

shell script to relace IT with CSC in a file using perl substitute command.

#!/bin/ksh
/usr/bin/perl -i -pe 's/IT/CSC/g'

Kamitsin,
It smells like homework.

i need to replace the string in unix file.
On opening the same file am getting line too long error. So using sed will not work.

Thanks for ur reply