if (-d "/proc/$pid") { ... }

##</code><code>##

    sub GetProcessCommand
    {
            my ($pid) = @_;

            return (open (PID, "/proc/$pid/cmdline") && <PID>);
    }

##</code><code>##

    # Check for buddy named 'xyz-proc'
    if (GetProcessCommand($pid) =~ /xyz\-proc/) { ... }