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.
While creating some ISO images for backup purposes earlier this week, I got the error message "Incorrectly encoded string" and "Possibly creating an invalid Joliet extension" when using genisoimage/mkisofs to create the image.
This article looks at how to mount a USB flash card reader and flash cards plugged into it with Linux. Also covered is how to make it easy to mount with a desktop icon in KDE and how to scan the SCSI bus to locate the device name and number.
When trying to install the PECL timezonedb module onto one of my webservers the other day, I discovered that the PECL library was not installed. (PECL is a repository for PHP extensions). I did a Google search for how to install PECL but couldn’t find anything to help. In the end I managed to work out that by installing PEAR, PECL is installed as well.
When you connect to a host using SSH or SFTP it does a series of checks to ensure you are connecting to the host you are expecting to connect to. One of these is a reverse lookup on the IP address to check the hostname is the same as the hostname you are connecting to. If it’s not, you’ll get an error message like "reverse mapping checking getaddrinfo for … POSSIBLE BREAK-IN ATTEMPT!". The post looks at a solution to this message.
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.
