My Question is
-----------------
Assume you've a directory (i.e /home/test/) which contains n number of files,
rename all the files which has byte count more than zero (0) with .bak extension.
Write shell script to achieve this output,
execute the same without using". / " in front of program name.


Could someone help me?

Seems more like a homework to me :-)
Why dont u do a little googling and find it out - its really easy

this will help u in increasing your knowledge

~Sage

i could not find it

The work can be done with the commands : ls for test basename mv

Here is a very simple version of the script

for i in `ls -l /home/test/*`
do
if [ -s $i ]
then
mv $i $i.bak
else
continue
fi
done


~Sage

hi,
When i run the code given by you it renames all files irrespective of .bak extension like

before:
student.txt

after code is run
--------------------
student.txt.bak

this is same for all other files including .bak file
i.e if a file exists with name tst.bak
after the code is run it is made as tst.bak.bak.