Tip of the Trade: Readline is the library that handles Linux command-line input as well as input for applications. Most of the default settings work perfectly well, but some change the way tab-completion behaves and thus require modification.

Tip of the Trade: The default values in /etc/hosts used in several Linux distributions have long been known to cause issues. Here's how to fix them in Apache 2.

Tip of the Trade: A here document, or heredoc, is one way to get text input into a script without feeding it from a separate file. If the data or script is complicated, however, keeping the two separate is generally a better idea.

Tip of the Trade: Hard disk thrashing? Check out Iotop, a Python program similar to top that enables you to keep an eye on disk I/O.

Looking to experiment with cloud computing? With Ubuntu Enterprise Cloud, it's easy to turn ordinary servers into cloud servers and build a private cloud.

Tip of the Trade: Booting from a USB stick can be very useful, but it's not an option for netbook users. With usb-creator from Ubuntu, however, it's possible.

Mail server admins are quietly living out a past that never happened: A rule in SpamAssassin intended to stop spam dated outrageously in the future is snaring anything with a 2010 date.

Tip of the Trade: Feeling like the only one stuck in the office this week? Here are some Linux command-line 'Christmas' Eggs to help you while away the hours.

Tip of the Trade: Less chocolatey, but more useful. Since 2000, the Perl Advent Calendar has been providing a useful Perl module each day from December 1 through Christmas Eve.

Tip of the Trade: The flip-flop operator in Perl is quite useful for comparing arguments, but it does have some surprising quirks.

Are your Hyper-V virtual machines secure? Learn how to secure them using Authorization Manager.

Last week we looked at special Perl variables for reading things in; this week we look at the other side -- variables that are useful when you want to write things out.

Tip of the Trade: Perl is a great tool for reading in information from a file. Several useful special variables can be used to neaten up code or alter the default behavior when reading in records.

Tip of the Trade: Have typos in your email file names. Hey, it happens to the best of us! Normally, it's an easy fix, but if you have a file with a name starting -, it's not so easy. To fix this, you need an escape sequence for rm itself, not the shell.

When deploying virtualization technologies, key choices must be made to ensure the environment is secure. This article explains how to use Authorization Manager to make Hyper-V as secure as it can be.

Not every scheduled task can take place on an always-on machine. For those we have anacron. With anacron, like cron, you schedule a job to run at specific intervals. Unlike cron, when the computer is switched on the anacron daemon checks whether a task should have run and if one was, it runs it.

Superuser privileges bring inherent risks with them, yet you can't run a corporate IT system without granting some people the privileges to do system-level tasks. There are ways, however, to minimize the impact.

Tip of the Trade: The command-line mail client mutt may be old school, but it features a wide range of keyboard commands that can be used for various useful tasks.

Group Policy Preferences makes it possible to reap the biggest benefits of an Active Directory environment by simplifying client management. Control Panel Settings help facilitate this.

Tip of the Trade: ssh-agent makes it possible to avoid having to type in a passphrase for each login. Helpfully, since the Leopard release on Mac OS X this functionality is built straight in.

Tip of the Trade: Indentation may seem an insignificant step when coding, but Vim makes it automatic with its indent option, indentexpr. This powerful yet flexible tool indents based on expression.

Tip of the Trade: Sometimes you want to use a "do-not-reply" type of email address and you don't want to have to mass-delete the mailbox at intervals. Here's an easy way to add a Postfix virtual alias to /dev/null.

Tip of the Trade: Want vim to share newlines? You're only two characters away.

Tip of the Trade: When it comes to Linux, Google Chrome may be far from gold, but it sure is shiny -- and fast.

Tip of the Trade: If df and du are getting you down, consider Baobab. This graphical alternative, installed by default in most Gnome-based Linux distros, gives you a clear picture of your disk usage.