Thank you monks for your wise and astute observations. I have included in my script that wisdom which fits with its purpose. Other wisdom is still being digested...(yummy). The check_private_dir sub seems twisted and its only purpose it to make sure there is a protected dir to write to, if anyone can enlighten me with more elegant code, I'd be smarter for it (and thankfull). UPDATE: I suppose I could create the private dir in /var/tmp, which on my systems is not cleared upon reboot, and I could remove all but one line from check_private_dir to test for the existance of the directory. However, I'd still be intersted in a cleaner way of executing the current check_private_dir for academic purposes. 
#!/usr/bin/perl -w
# Run this perl code from cron every 5 minutes
# 0,5,10,15,20,25,30,35,40,45,50,55 * * * * /.ping_hosts.pl 2>&1 
#

use strict;
use Net::Ping;
my $private_dir = "/tmp/ping_hosts_dir";

sub check_private_dir {
    unless (-e $private_dir){ mkdir($private_dir, 0700) or die "Can't 
+mkdir $private_dir\n" }
    if (-d $private_dir) {  
        my $dec_mode = (stat($private_dir))[2];
        my $oct_mode = sprintf "%lo", $dec_mode;
        if (-O $private_dir and ($oct_mode == 40700)) { return }
        elsif (-O $private_dir and ($oct_mode != 40700)) { 
            chmod(0700, $private_dir);
            return;
        }
        else { die "We don't own the directory\n" }
    }
    else { die "$private_dir exists and is not a directory\n"; }
}

sub ping_hosts {
    my $ws;
    my $timeout = 2;
    my @hosts = qw(host1 host2 host3 host4); 
    my $ping_obj = Net::Ping->new("icmp");
    foreach $ws (@hosts) {
        unless ($ping_obj->ping($ws, $timeout)) {
            print "$ws did not respond to ping within the $timeout sec
+ond timeout period\n";
            notify_admins($ws);
        }
        sleep(1); # To prevent flooding
    }
    $ping_obj->close(); # Redundant since open network conn is auto-cl
+osed when leaving sub
}

sub notify_admins { # Called from ping_hosts()
    my $ws = shift(@_);
    my $nfile = "${ws}.notify";
    my $admins = "admin1\@mailhost.com, " .
                "18005551212\@page.com, " .
                "admin2\@mailhost.com, " .
                "19005551212\@page.com";
    unless (-e "${private_dir}/${nfile}") {
        open(NOTIFY, ">>${private_dir}/${nfile}") or die "Can't create
+ notify file\n";
        close(NOTIFY);
        open(MAIL, "|mailx $admins") or die "Can't fork for mailx: $!\
+n";
        print MAIL "$ws doesn't respond to ping\n";
        close(MAIL);
    }    
}

### MAIN ###
check_private_dir();
ping_hosts();

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In reply to RE: lock files vs. non-predictable file names by RuphSkunk
in thread lock files vs. non-predictable file names by RuphSkunk

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