[or… how I learned to stop worrying and love the /etc/group file] On Red Hat, the default permissions for a serial port are: ls -l /dev/ttyS1 crw-rw—- 1 root uucp This means that root is the owner and group is uucp. No others have access to the serial port. In order for a non-root user […]
Granting access to the modem for a regular user on Red Hat GNU/Linux
Creating a Serial Console Bootdisk for Red Hat 8.0
In this article, we showed how to build a serial port multiplexer that allows up to 16 different servers to be controlled from one serial port. We needed to upgrade our servers to 8.0, and, of course, we wanted to use the serial port to do it rather than lug a monitor and keyboard over. […]
Modifying a Red Hat 8.0 Install Diskette
In this article I struggled with a Barracuda ST15150N drive that had problems with Tagged Command Queueing. Well, it is nice to have an install diskette that works with a serial console and works with the ST15150N. This article will guide you through the modification of a stock RedHat install boot disk. I will start […]
Stupid Bash Tricks: Magic Carets Correct Munged Commands
We all have fat fingers sometimes and mistype commands, often transposing letters in a word or leaving letters out. When using Bash, you can fix it with the magic carets instead of retyping the whole command. example: [root@pippi opt]# usradd -u 666 -g 100 udergahad bash: usradd: command not found Oops, it should be “useradd”. […]
Using Samba to Authenticate GNU/Linux Against Active Directory
Samba 3.0 allows Linux to authenticate against Active Directory and access shared resources on a Windows 2000 server. Samba 3.0 is still beta. For info on the status, see the status page at samba.org. This article will detail the procedure to get this running with Red Hat 8.0. First, get the Samba distribution from samba.org. […]
Meet the Amazing Mr. lsof
Buoys and gulls, I’d like to introduce the lsof command. Say that you were moving a whole bunch of files, and there was no indication of what file was currently being moved? lsof shows (lists) open files. For instance, if you were moving a bunch of files from directory sales, you could see exactly what […]
Using Ksysv to Manage System V Run Levels
The System V init scripts are a bear to configure by hand. We discussed using chkconfig in this article. Ksysv, part of KDE, provides an easy to use GUI interface. Just drag the services to the appropriate place. The priority number, K/S prefix, and symlinks will all be set up automatically. Backup up all of […]
Minicom Compile/Install
Minicom is a simple terminal program. We use it to access our servers via our serial port mux. Most likely your GNU/Linux distribution has Minicom as an available package. If not, or you would rather compile yourself, grab minicom from here. Unpack the sources in your favorite spot and compile: # cd mini* [minicom-2.00.0]# ./configure […]
Distributed Compile With Distcc
Ever wish you could harness the power of many boxen to compile those large projects like KDE, or the LInux kernel? Well, you can, with distcc. We grabbed version 1.5, and compiled it on srv-33 and srv-34, two machines with P133 processors: # cd /usr/local/src # tar -xzf distcc*.gz # cd dist* distcc-0.15]# ./configure && […]
Running Linux on Sparc64
If you have some old Sun hardware you would like to run GNU/Linux on, the easiest way to get started is to use the CD-ROM images available at Aurora Linux. We’ve tried many different distributions, but the only one that we could get to load successfully is Aurora. Mebbe we are braindead, but if you […]
Gentoo Migration With Dump / ST15150
We have an old Sun box that won’t even run Solaris 8. Plus, Urbana wants to run Solaris 9 on the good Sun box, not GNU/Linux. After we optimized our system with Gentoo, we didn’t want to redo the compiles, especially on this slower box. We did a dump of the filesystem, installed Aurora on […]
Stupid Bash Tricks: Simple Loop With Timestamp
We ran into an interesting situation where we needed to know two things: whether or not a particular server was down, and when, exactly, it went down. We had requested some service be done on the server, and had a shell open via ssh. A simple solution that did the trick, and illustrates some stupid […]
Optimizations for Pentium4 and gcc 3.2.2
We run Gentoo, and in our make.conf file we had CFLAGS=”-march=pentium4 -O3 -pipe -fomit-frame-pointer”. Well, it turns out there is a bug. If you run this script: python -c ‘int(10.1); int(10000.3); int(1.2)’ You will get an overflow error. The fix is to use CFLAGS=”-march=pentium3 -mcpu=pentium4 -O3 -pipe -fomit-frame-pointer”. We just ran emerge glibc, and the […]
Linux From Scratch Book With CD
Linux From Scratch is a GNU/Linux distribution that you compile and piece together yourself. Gerard Beekmans and the LFS team have published LFS 4.1 as a book with a companion CD. We think that this is a fabulous way to document the heart of GNU/Linux. Own your own distribution. Don’t be buffeted about by corporate […]
GNUkes of Hazzard
For a serious analysis of what is going on with the whole SCO/IBM thing, check out the OSI Position Paper. But, for some Friday fun, check out The GNUkes of Hazzard.
Roll Your Own RPM
Building from source is fun, but it’s easier to distribute RPMs to a bunch of machines. You may recall that we recently built and installed the OpenTDS libraries and SQSH, a dandy little command line tool for use with MS SQLServer. These built nicely on my RedHat 7.3 system, and I have a bunch of […]
Sync Sync Halt
Urbana used to work with a guy who routinely shut down GNU/Linux by typing: sync sync halt That just sounded plain crazy. Why not use shutdown? Well, we just figured he was just a little old-school. The command appeared to work (manpage for sync, manpage for halt). Now, our robocoop is running a giagd system, […]
How Many Open Files?
We knew the answer to this question once, back when the world was young and full of truth. Without hesitation, we’d have spouted “Just take the output of lsof | wc -l!” And it’s true enough, in a general sort of way. But if you asked me the same question now, my answer would be: […]
The Red Hat Dilemma and One Solution
Red Hat’s maintenance policy is nasty. On the one hand, they need to make money, and maintaining distributions is expensive. On the other hand, for those of us who use Red Hat in budget environments, we can’t really afford their advanced server product, and can’t afford to change to a new version every year. One […]
Analysis of SCO’s Las Vegas Slide Show
Check out Bruce Perens’ analysis here, and ESR’s An Open Letter to Darl McBride.