Hi Suba,
if sy-uname = 'XXXXX'.
do something.
end if.
the above code which u said is generally used to get easier during debuugging of code, but it not recommended to move the that code with those lines to production.
or i guess u can go with building ranges for usernames and check..
if sy-uname = r_usernames. ( r_usernames contain all the usernames)
do something.
end if.
thanks,
Azhar