NIS, NIS+, or Standalone

I am trying to write a little script to determine is a UNIX system is using NIS, NIS+, or a standalone system. Any suggestions on how to approach this? Thanks in advance! Hans

Check file permissions

Is there a module or command that returns the permissions of a file or directory? Thanks, Hans

getpwent & getgrent

Are there any equivalent functions for getpwent or getgrent in the NIS environment? I am able to get the local password information using these functions. Can they be extended to query the NIS information? Thanks!

Check to see if process exists

Is there good way to execute a UNIX 'ps' command from Perl and check to see if a process is running or exists? For instance, I would like to check to see if Sendmail is running. Under a UNIX shell command you can execute, '/usr/bin/ps -ef | grep sendmail'. Is there an easy way to do this in Per

Perform a tar command on a directory

Does anyone have a good suggestion how to go about creating a tar ball of a directory from within a Perl script? I considered doing a change directory just above the directory which I want to tar and then using the UNIX tar command from within the script. Is this the best approach? Thanks! Hans