I'd like to grab the percentage of memory/CPU that is being used by the user, and return it to two scalars for use in a script. I would think this would be a fairly common task, however Google has failed me. I was trying to wrap my head around the best regex to use on the results from `top -b -n 1 -u $username`, but decided to ask here first.

Edit: Sorry, I figured that posting extremely basic code when the main piece was the regex would be pointless, especially when I wasn't sure I was doing it the best way, but someone hit me with a book, so I'll post some basic example code.
Note: Code not guaranteed or likely to be error free.

#!/usr/bin/perl
use strict;
use warnings;

my $memlimit = "25.0"; # maximum percentage of memory user can use
my $cpulimit = "25.0"; # maximum percentage of CPU user can use

my $username = `whoami`;
my ($usermem, $usercpu) = getUserMemCPUperc( '$username' );

if (($usermem < $memlimit) && ($usercpu < $cpulimit)){
#  do stuff!
} else { # memory or CPU limits reached
  exit(0);
}
exit(0);

sub getUserMemCPUperc {
  my( $username ) = shift;
  my $top = `top -b -n 1 -u $username`; # gets top from the system
  my ($cpu, $mem);

  $_ = $top;
#  @processes =~ /.../g; # regex to extract each process line
#  foreach my $process (@processes) {
#    my ($procpu, $procmem) =~ /.../; # get cpu and memory percent
#    $cpu += $procpu; # add process cpu percent to total
#    $mem += $procmem; # add process memory percent to total
#  }
#  return ($mem, $cpu);
}

[download]

So, how would you do it?

Edit: Code that seems to work is posted below in reply. Originally trying to do research to figure out how to do this, I saw that top gave me exactly what I wanted, however this seems like a convoluted and inefficient method.

Edit: Proc::ProcessTable will not seem to work on my CentOS version, so I'll be working on improving the version posted below. Suggestions would be appreciated.

In reply to Percent of CPU/Mem Usage for User by geekt

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