Suppose your new web application is really starting to take off, with new users registering by the hour. Like a stock IPO, chances are you and your colleagues are regularly peeking the user count. But, constantly logging in to and out of MySQL just to execute a simple query is aggravating. However, if you're otherwise logged in to the server, you can create a shell alias that will log in to the MySQL server, select the appropriate database, and execute a specific command:

Given the proper codecs, in Linux you can play almost any digital audio format. Linux has many graphical applications that can do the job, such as Amarok, Rhythmbox, Audacious, and XMMS, all of which provide an intuitive user interface, playlist sorting, and various other options. But what if you want low resource usage so you can play tunes on aging hardware? Here are some alternative players for the Linux command line.

There is literally no dearth for music player applications in Ubuntu. Banshee, which is the new default music player for Ubuntu 11.04, is among the best you can get. Alternatives include Clementine, Rhythmbox, Amarok, DeadBeef among others. But MPD(Music Player Daemon) and NCMPC(an MPD client) combination opens up a whole new genre of music players for Ubuntu power users. Folks who like tools like Twidge Twitter Client are gonna adore this.

Finally, as was the case back in school, the "sixth W," how, comes last. There is no how or howis command. But if your system isn't complete without that final question, there is a simple solution. Enter the following command to give your Linux box a useful and convenient how: ln -s /usr/bin/man /usr/bin/how. And just like that, you have all of your Ws (and your H) covered.

Nail is a lightweight console-based mail client, made to be a modern replacement for the ancient mailx command. It's fully compatible with mailx, but has a lot more features, which makes it appropriate for everyday use. Nail supports POP3, IMAP, and SMTP out of the box, so there's no need for further programs like Fetchmail or Postfix. It also has a built-in Bayesian spam filter, so you don't need external tools like SpamAssassin.

This time I've gone too far. Espousing the use of a text-based web browser is like encouraging honesty at Microsoft. The very notion of a text interface for the Web runs against the grain. Nonetheless, that's what we're doing this week here on the CLI frontier. Come read about a lean, mean, text-based browsing machine that's faster than a lynx. Actually, it is a Lynx.

Based on ncurses, MOC (music on console) is a popular, text-based audio player which can play various audio formats, including Ogg Vorbis, FLAC, MP3, MP4, WMA and WAV. The release I'm going to talk about in this article is 2.5.0-alpha3, as it comes with Debian Lenny.

We're going to look at a few programs he maintains -- if we can borrow a phrase from another famous coder -- just for fun.

The download page for each of these games is linked to from the game title in the section heading. A man page is included with each source code tarball. You should probably consider reading the man page a prerequisite for game play.

One of the nicest facilities of the modern shell is the built in "completion" support. These facilities allow you to complete commands and their arguments easily. Read on for a brief introduction to adding your own command completions.

Like it or not, but sooner or later you realize that you'll have to write shell-scripts to administer UNIX. And among these scripts there certainly will be those to cooperate with interactive applications such as telnet, ftp, su, password, ssh. But it means the end of the admin's quiet life because while dealing with interactive programs one often come across numerous hidden traps which doesn't usually happen with ordinary sh-scripts. Though fortunately or may be not, but most of these problems generally turn up within first five minutes of the work under the script. The symptoms typically look like that author can't pass the authentication from the script.

There are lots of ways the CLI can help you. Often, you don't need to do something so much as you need to know something. This week we'll take a quick look at several commands -- whereis, whatis, df, kernelversion, ifconfig, route, and last -- that can quickly answer questions about your system or configuration. Wipe that GUI mess out of your eyes and meet me at the CLI.

Advanced permissions can be very useful, but very dangerous as well. Let's talk about SUID, first. This permission is meant to be used on executable program files only when strictly necessary. In my opinion, it is better not to use them at all. They can provide an excellent backdoor for a hacker if used not in the right way.

The guide aims first-time users and average Linux users and its goal is to make you learn your way around when using the Linux command-line interface (or CLI for short). It also encourages some habits which I believe that, although hard to learn at first, will make you more productive later on.

I divided this guide in several sections, so feel free to jump to whichever you want using the links below: