"Thanks Ken, for bringing up getpwent. BTW, i used the other approach which did not mention getpwent, but still the job was done, ..."

You're welcome. I'm glad you found a working solution.

For future reference, all of that code could have been replaced by:

while (my @pw = getpwent) {
    printf "UID is: %s\nGID is: %s\n", @pw[2,3]
}
[download]

By the way, take a look at open for better ways of doing: open("$HAN", "$FILE")