getgrgid

getgrgid 
gid

Retrieves a group file ( /etc/group ) entry by group number gid . The return value in list context is:

($name, $passwd, $gid, $members)

where $members contains a space-separated list of the login names of the members of the group. If you want to do this repeatedly, consider caching the data in a hash using getgrent . In scalar context, getgrgid returns only the group name.