perl -e'sleep' httpd And your code will not detect that httpd is gone.

Besides that, your code only notices when a process is gone. Far more often, in my experience, processes are still there, but don't work properly. So instead, test the functionality. For example, I use this hack to restart my apache when needed:

#!/usr/bin/perl

use strict;
use LWP::Simple;

exit 0 if -e "/etc/nouptest";

eval {
    local $SIG{ALRM} = sub { die "Alarm\n" };
    alarm 10;
    my $p = get 'http://uptest.convolution.nl/';
    $p =~ /xyzzy/ or die "Down\n";
    alarm 0;
};
if ($@) {
    if ($@ =~ /Alarm|Down/) {
        system qw[/etc/init.d/apache stop];
        sleep 3;
        system qw[killall -9 apache];
        sleep 3;
        system qw[/etc/init.d/apache start];
    }
}
[download]

Cron runs this every minute and it arranges for me to get mail when Apache was restarted (because the init scripts have output). As a nice side effect, this way I get lots of mail when the nameserver is broken :)