#!/usr/bin/perl -w
# The following example code uses IPC::System::Simple to mount
# a /mnt/backup directory, run an rsync command, and then unmount
# the directory again.
use strict;
use IPC::System::Simple qw(run capture);
use POSIX qw(nice strftime);
use Fatal qw(open close nice);
use constant NICE_VALUE => 10;
die "Must be root" if $> != 0;
nice(NICE_VALUE);
my $mounted = 0;
my $today = strftime('%Y-%m-%d',localtime);
# The capture() from IPC::System::Simple either works, or dies.
my $machine_name = capture("hostname");
open(my $mtab_fh, '<', '/etc/mtab');
while (<$mtab_fh>) {
if (m{/mnt/backup}) {
$mounted = 1;
last;
}
}
close($mtab_fh);
if (not $mounted) {
# Our run() from IPC::System::Simple either works, or dies.
run(qw(/bin/mount /mnt/backup));
}
my $last_backup = '';
foreach my $dir ( glob("/mnt/backup/$machine_name/*") ) {
next if not -d $dir;
# 'gt' is correct here, since we're delaing with YYYY-MM-DD
if ($dir gt $last_backup) {
$last_backup = $dir;
}
}
die "Cannot find last backup" unless $last_backup;
# 0 - Successful backup
# 24 - Files disappeared during backup. This is expected on
# an active filesystem, and not considered an error.
run([0,24],
qw(/usr/bin/rsync -aH --exclude-from=/etc/rsync-ignore),
"--link-dest=$last_backup","/",
"/mnt/backup/teddybear/$today",
);
# Unmount our filesystem if we found it unmounted to begin with.
# Again, run() either succeeds, or dies.
if (not $mounted) {
run(qw(/bin/umount /mnt/backup));
}
