Cobbled-together backup routine. (Don't use this without modification)

gistfile1.pl

#!/usr/bin/perl

use strict;
use warnings;

$< and die "This won't work unless run by root";

my @errors;
sub log_error {
    push(@errors, pop);
}

my $lock = "/var/root/.nightly-backup.lock";
sub unlock {
    unlink $lock;
    exit(1);
}


my %directories = ( 
                    "/Users/" => "/Volumes/Users-backup/",
                    "/etc/" => "/Volumes/slash-backup/etc/",
                    "/opt/local/" => "/Volumes/slash-backup/macports/",
                    "/var/root/" => "/Volumes/slash-backup/root/",
                    "/usr/local/" => "/Volumes/slash-backup/usr/local/",
                    "/var/log/" => "/Volumes/slash-backup/logs/",
                );


my $rsync = `which rsync`;
chomp $rsync;

my $args = "--delete -ahv";

my $dry_run = grep (/-n/, @ARGV);
$dry_run and $args .= " -n";


while (-e $lock) {
    log_error("Another backup job was running");
    sleep 30;
}


system "touch $lock";    
$SIG{$_} = \&unlock for qw/INT TERM TSTP HUP QUIT/;


my $now = `date`;
while (my ($origin, $dest) = each %directories) {
    
    if ($origin eq $dest) { 
        log_error("Backup origin \"$origin\" is the same as destination\"$dest\"");
        next;
    }

    unless (-e $origin) {
        log_error("Backup origin \"$origin\" not found. Aborting...");
        next;
    }

    unless (-e $dest) {
        log_error("Backup destination \"$dest\" not found. Aborting...");
        next;
    }

    my $command = "/usr/bin/nice -n19 $rsync $args \"$origin\" \"$dest\"";
    system "$command";
}

# Email root to let him know
open MAIL, "|/usr/bin/mail -s \"Backup initiated $now\" root";
print MAIL "Started at: $now";
$now = `date`;
print MAIL "Ended at: $now\n\n";
print MAIL "ERROR: $_\n" for @errors;
close MAIL;

unlock;