How to display information of the script while its running?

Shell Programming and Scripting
1

how to display the messages on screen IN PERL such as "

  1. Entering while loop" if the script enters a while loop.

  2. Checking FILENAME. etc...

  3. Print statement is also not helpful....

2

You mean like debugging information, which prints lines as it runs code without needing print statements? Try the Perl Debugger perl -d scriptname

It's a bit more complicated than set -x since it's an interactive debugger, but not that complicated. The s command tells it to run the next line, and you can repeat that command by holding down enter. q quits.

See man perldebtut for more complete instructions.