As we mentioned in the Remote Power Console article, we have a lab of 16 servers that we are using to test various configurations we will use in articles for NetAdminTools.com. We needed a way to access the consoles of the servers via a serial port, but we didn’t want to plunk down $500 or […]
Serial Port Multiplexer
Aliases & Functions in Bash
You might save some time and have a little fun by putting some aliases and functions in your .bashrc file. You can put functions or aliases in .bash_profile or .bashrc in your home directory. But by using .bashrc instead of .bash_profile, they’ll be read in not only when you log in, but whenever you start […]
Adding Swap Space on the Fly in Linux
Sometimes in the course of a system’s existence you find that the swap partition you set up at install-time just isn’t enough anymore. Maybe you’re upgrading your system to RedHat 7.1 from a version of RedHat that used less swap in relation to physical RAM. Perhaps you’re running Oracle. Or maybe you’re adding more memory […]
Linux Kernel 2.4.9 Released + some tips
You can get it from the mirrors here: kernel.org/mirrors or here: kernel.org. Check our our article on compiling the Linux kernel. One trick we’d like to remind you of from the article is to use “make oldconfig” to migrate your old .config file (usually in /usr/src/linux). You will be asked about just the options that […]
Aliases & Functions in Bash
You might save some time and have a little fun by putting some aliases and functions in your .bashrc file. You can put functions or aliases in .bash_profile or .bashrc in your home directory. But by using .bashrc instead of .bash_profile, they’ll be read in not only when you log in, but whenever you start […]
Kernel recompile
Before you do anything else, make sure you have a way to boot the OS. Make a bootdisk and test it. Get the source for the kernel and put it in /usr/src. cd /usr/src tar -xzf <kernel source file name> The kernel source lives in /usr/src/linux. Linux is usually a symbolic link to the source […]
Determine version of running kernel
uname -a You’ll see something like this: Linux u-1.signalq.com 2.4.6 #2 SMP Sat Jul 14 09:02:08 PDT 2001 i686 unknown
Using RPM
One task that we often do is remove rpms that are installed by default. In this example, we will find out what rpm apache uses and we will uninstall it. What we need to do is find the name of the apache package: [root@srv-3 RPMS]# rpm -qa | grep apache apache-1.3.19-5 [root@srv-3 RPMS]# So, we […]
Linux From Scratch Version 3.0 Released
For those of you who wish to learn more about how a GNU/Linux system is put together, or if you want to have more control over your GNU/Linux system, check out Linux From Scratch (LFS). The commands for building a system from scratch are provided, as well as step-by-step instructions and explanations. Simply download the […]
Automated creation of GNU/Linux systems w/ XML spec file
I’ve mentioned Linux From Scratch in previous articles. I’ve discovered another tool related to this project that rocks called ALFS, or Automatic Linux From Scratch. ALFS puts all of the specifications for compiling a linux system into an XML document and generates most of a Linux From Scratch system automatically. There are a couple of […]
Filesystem Hierarchy Standard
For those of you managing GNU/Linux systems, you are certainly familiar with the wide range of filesystem heierarchies and utility locations. This makes it difficult to move between different vendors’ distributions. This is changing, in a large part due to the FHS standard. Check it out: http://www.pathname.com/fhs/
Linux Kernel 2.4.12 Released
It is a good idea to test this and upgrade to it if you are running a 2.4 kernel. There have been some problems with virtual memory with some of the 2.4 releases. There was also a nasty bug with symlinks w/ 2.4.11. Get it from: Kernel.org Mirrors. Seems to work fine for us. We […]
Booting Linux (For Wusses)
There are two main bootloaders you can use with Linux these days: LILO and GRUB. Red Hat uses GRUB by default now. Most distributions used LILO until quite recently. We built a fairly souped up Linux workstation w/ a large Maxtor IDE drive. We decided to use Sorcerer GNU/Linux; however, we had a horrid time […]
Linux Workstation w/ Geforce2 and Asus P4B
It has been awhile since we have purchased workstation hardware for a new system. We settled on the Asus P4B w/ a Geforce2 MX400 AGP video card. As of February 2002, it seemed like the best CPU value was a P4 1.7GHz. We are running Sorcery GNU/Linux so we can squeeze out all of the […]
Using chkconfig & /sbin/service to manage run start up scripts in RedHat
Red Hat includes the checkconfig & service utilities to help you manage your start up scripts and save you a lot of typing. This is handy when you’re adding your own services and also in managing the already existing services. chkconfig is available if you want to use it on other distributions that may not […]
File system recovery via the serial port w/ Linux
In our article Serial Port Multiplexer, we documented a design for a shoestring budget console sharing device. Basically, if you have a bunch of servers that can run their consoles via a serial port, you can use our device to monitor all of these consoles remotely. Well, one of our boxes is sick, and we […]
Red Hat Errata
If you are running Red Hat, you need to keep your RPMs up to date. Red Hat has a service you can subscribe to, but if you wish to do this manually, browse to the house of mirrors, and pick a site that has updates for your architecture. We put all of the updates in […]
Compiling Kernel, modules for Red Hat
One problem with Red Hat systems is that the kernel config is not as simple as, say, Slackware. You can’t simply just select the modules you think you need, add in devices, etc. and have the system boot correctly. The Red Hat config is quite customized. This is particularly true for workstation configs that use […]
Stupid Bash Tricks: Repeat Last Argument to Last Command
Did you know that you can recall the last argument to the last command you typed by using the special variable !$. This can be handy when you are working with host names, long file names, all sorts of things. A few examples: See if a host is up and log in: usr-3@srv-3 usr-3]$ ping […]
Fun With Modules
We ran into a couple of interesting problems with modules. The first one dealt with SCSI emulation with IDE drives. You need SCSI emulation if you want to write to your IDE CD-ROM with Linux tools. In the past, we have recompiled the kernel with SCSI emulation, but it is so much easier if you […]