Grepmail Search for emails in a normal or compressed mailbox using a regular expression or date constraint.
archivemail is a tool written in Python for archiving and compressing old email in mailboxes. It can move messages older than the specified number of days to a separate mbox format mailbox that is compressed with gzip, or optionally just delete old email.
remoteactions is a set of Perl scripts which you can use to run commands on remote servers. A connection is made over an ssh tunnel, authentication is performed, the specified command is executed and the output is sent back through the tunnel. Unique status codes can be prefixed to each stage of operation, allowing you to collect as much or as little diagnostic information as you need. Alternatively they can be suppressed entirely (for example if the remote command outputs binary data).
Daemons
dnsmasq Dnsmasq is lightweight, easy to configure DNS forwarder and DHCP server. It is designed to provide DNS and, optionally, DHCP, to a small network. It can serve the names of local machines which are not in the global DNS. The DHCP server integrates with the DNS server and allows machines with DHCP-allocated addresses to appear in the DNS with names configured either in each host or in a central configuration file. Dnsmasq supports static and dynamic DHCP leases and BOOTP for network booting of diskless machines.
Plugins
mod_curb - A cumulative bandwidth limiting module for Apache This module was written to solve the problem of limiting the bandwidth usage of a hosted website. Several small hosting companies will happily give you a co-located box with a set data transfer limit, such as '2Gb of traffic per month'. They will charge you extortionantly if you go over this limit... I've looked around and I can't find a simple software solution to limit the data that Apache will serve, so I wrote one.
Articles, Tutorials and HowTos
Easy Automated Snapshot-Style Backups with Linux and Rsync This document describes a method for generating automatic rotating "snapshot"-style backups on a Unix-based system, with specific examples drawn from the author's GNU/Linux experience. Snapshot backups are a feature of some high-end industrial file servers; they create the illusion of multiple, full backups per day without the space or processing overhead. All of the snapshots are read-only, and are accessible directly by users as special system directories. It is often possible to store several hours, days, and even weeks' worth of snapshots with slightly more than 2x storage. This method, while not as space-efficient as some of the proprietary technologies (which, using special copy-on-write filesystems, can operate on slightly more than 1x storage), makes use of only standard file utilities and the common rsync program, which is installed by default on most Linux distributions. Properly configured, the method can also protect against hard disk failure, root compromises, or even back up a network of heterogeneous desktops automatically.