Unix is a multi-user, multi-tasking operating system that was initially developed by Bell Labs in the 1970s. Various similar operating systems that are POSIX compliant (ie compatible with Unix) have since been developed (POSIX is an abbreviation for Portable Operating System Interface for UNIX). These include the following: the BSD family (OpenBSD, FreeBSD, NetBSD, Mac OS/X), Solaris, IRIX, AIX, SunOS, UnixWare, OpenServer and Linux.
Software written for POSIX compliant operating systems is generally able to be compiled for all POSIX platforms with little or no platform-specific changes. This makes the commands and utilities available for this extended family of operating systems very similar, and there are few differences between administering them.
The articles in this section are about useful command line utilities and commonly used application software on POSIX compliant operating systems. For Mac OSX specific articles see my OSX section.
I recently needed to set up a CentOS 5 box and completely forgot how to set the timezone. There’s apparantly a nice easy text GUI for doing it in RHEL but I couldn’t find the same thing on the CentOS box so here’s how to do it. It should also work for most Linux systems.
logwatch is a system log analyzer and reporter which emails daily reports about information in the system log files in /log. On CentOS and Red Hat Enterprise Linux this is usually configured by default to email the root user on a daily basis with the results from the log analysis. This post looks at how to stop logwatch from reporting on a particular service, for example sendmail and postfix.