From O'Reilly SysAdmin:

Employee turnover in most organizations runs high. So unless you run a small shop with a stable user base, you need to learn how to clean up after an employee leaves. Too many so-called system administrators do not understand the stakes involved when they manage users. Disgruntled former employees can often cause significant trouble for a company by gaining access to the network.

Read the full thing at http://www.oreillynet.com/sysadmin/blog/2006/03/howto_remove_an_user_and_impro.html

From Linux.com:

You may know how to use SQL to extract data from a table in a MySQL database, and how to run a query that combines data from more than one table. But what about multiple databases? Or even multiple databases on multiple servers?

Read the full thing at http://www.linux.com/article.pl?sid=06/02/22/2050253

From Linux.com:

Working with free and open source software, one frequently hears terms such as bugs, updates, and patches. When developers come across shortcomings in their software, instead of repackaging the software with the changes, they can provide a patchfile that contains details of all required changes. Two important tools used in the process are diff, which creates a patchfile, and patch, which applies it. You can use both tools with text or HTML files.

Read the full thing at http://www.linux.com/article.pl?sid=06/02/16/1938203

From Linux.com:

If you have multiple servers with similar or identical configurations (such as nodes in a cluster), it's often difficult to make sure the contents and configuration of those servers are identical. It's even more difficult when you need to make configuration modifications from the command line, knowing you'll have to execute the exact same command on a large number of systems (better get coffee first). You could try writing a script to perform the task automatically, but sometimes scripting is overkill for the work to be done. Fortunately, there's another way to execute commands on multiple hosts simultaneously.

Read the full thing at http://www.linux.com/article.pl?sid=06/02/13/1413229

From SysAdminMag.com:

File integrity assessment (FIA) tools like Tripwire [1], Samhain [2], AIDE [3], et al. are commonly deployed in organizations to help assist forensic investigation after a security incident and as a host-based intrusion detection tool to help detect unauthorized file system changes (this also makes them useful monitoring tools for existing change control procedures, though that is not the focus of this article). The concept is simple: the administrator creates a configuration file that lists the critical system files and directories that the FIA tool should monitor, then uses the FIA tool to create a database that tracks common parameters about those files, such as permissions and ownerships, file size, and MAC times, along with one or more cryptographic checksums over the file contents (typically via common hashing algorithms like MD5, SHA-1, etc.). The FIA tool is then re-run periodically, and the current state of the file system is compared to the values stored for the various files in the database -- if there are any discrepancies, the files are flagged as having been modified and a report is generated.

Read the full thing at http://www.samag.com/documents/s=9950/sam0602a/0602a.htm

From Linux.com:

Other system administrators have fantastic toolboxes for their work. My tools consist of two everyday programs: OpenSSH and the GNU Bourne-Again Shell (bash). No other tool, whether console-based or GUI, has been so consistently useful to me as these two programs.

As a system administrator, I have used OpenSSH's piping abilities more times than I can remember. The typical ssh call gets me access to systems for administration with a proven identity, but ssh is capable of so much more. In combination with bash's subshell invocation, OpenSSH can distribute the heavy work, reduce trace interference on a system under test, and make other "impossible" tasks possible. I've even used it to make Microsoft Windows remote administration easier.

Read the full thing at http://www.linux.com/article.pl?sid=06/01/12/1937210

Learn how to run your personal, live-Knoppix configuration on any PC. MozillaQuest Magazine (MozillaQuest.Com) reports: ". . . in Part 4 of our Knoppix cheats article, you will learn how to put together all the stuff you learned in Parts 1 through 3 to make a very portable, Live-Knoppix setup. It's really very slick and it is very handy too . . . we are going to put the Persistent Knoppix image on the same USB key that we put the live Knoppix CD that we used for the performance cheats in Part 2. When we boot our Persistent Knoppix, we are going to use the cheat from Part 1 to force Knoppix to use the ALSA drivers. Moreover, we are going to chain the ALSA cheat and the performance cheat at the same boot: prompt as we learned to do in Part 3."

"The Knoppix live CD or live DVD together with a USB Key and the persistent Knoppix trick pretty much give you a portable computer on a disc and USB key. Considering that you can download the Knoppix live CD or live DVD at no cost, the only thing your Knoppix portable computer costs you is the price you pay for your USB key -- and that can be as little as $25 . . . The Knoppix live CD and live DVD are pretty much load and go operations. If a person can turn on a personal computer and drop a disc into the CD drive, that person can run and use Live Knoppix Linux . . ."

Check MozillaQuest.com for the full story and links!

From Howto Forge:

This tutorial describes how to install and configure OpenSSH so that it will allow chrooted sessions for users. With this setup, you can give your users shell access without having to fear that they can see your whole system. Your users will be jailed in a specific directory which they will not be able to break out of.

Read the full thing at http://www.howtoforge.com/chrooted_ssh_howto_debian

From Linux Journal:

Confused about what DHCP offers and how you can take advantage of it on your Linux system? Here are some tips and pointers.

Read the full thing at Linux Journal

Learn how to chain Knoppix cheat codes. MozillaQuest Magazine (MozillaQuest.Com) reports: "Today, in Part 3, this tutorial shows you how to chain Knoppix cheat codes so that you can use several of them in the same Knoppix session. It also shows you how to find lots more Knoppix cheats . . . You can chain as many Knoppix cheats as you like."

For example, you can force "Knoppix to use its default kernel and to use the ALSA sound drivers . . . [and] to use your USB key to read its live CD image and files from the USB key rather then from the CD drive . . . [and] to set your screen resolution to 1280x1024" all in one chained Knoppix cheats command.

"Today's tutorial builds on what you learned in 'Part 1. Cheat Code Basics and the ALSA Cheat Code', and in 'Part 2. Performance Improvement Cheats' to chain several cheats together at the same 'boot:' prompt."

Check MozillaQuest.com for the full story and links!