#!/usr/bin/perl                                                                           
use warnings;                                                                             
use strict;                                                                               
use Proc::ProcessTable;                                                                   
#usage: cpusage pid1 pid2 pid3.....                                                       
#run without args to get full list                                                        
#then run with chosen pids and it will update                                             
#every 5 secs. No output with invalid pids.                                               
my @pids=undef;                                                                           
my $t = new Proc::ProcessTable;                                                           
@pids = @ARGV;  #get pids to watch on commandline                                         
                                                                                          
if (@pids){                                                                               
while(1){                                                                                 
foreach my $p (@{$t->table}) {                                                            
  if(grep {$p->pid == $_}@pids){                                                          
    print "--------------------------------\n";                                           
    print 'pid ',$p->pid,' ',$p->cmndline,' ','CPU% ',$p->{pctcpu},"\n";                  
}                                                                                         
}                                                                                         
sleep(5);                                                                                 
}                                                                                         
}else{                                                                                    
foreach my $p (@{$t->table}) {                                                            
print "--------------------------------\n";                                               
print 'pid ',$p->pid,' ',$p->cmndline,' ','CPU% ',$p->{pctcpu},"\n";                      
}                                                                                         
}                                                                                         
exit(0);