Kategori: Linux and UNIX

Do you know how to check the IP address of a Linux server? ”Of course!”, you say, and you type this: $ ifconfig eth0 Not anymore! Both the command ifconfig and the interface name eth0 have been obsolete for a few years now. However, many organizations still use something like Red Hat Enterprise Linux 6, […]

Recently, I posted about basic permissions for Linux files; now let’s look at how to access those in a shell script. Testing file permissions is an essential part of enforcing an access control policy. Two common ways to test files for readability, writability, zero size and so forth are the if and the test. For […]

Red Hat Linux won’t play MP3 audio or MPEG video files. This isn’t a new issue. Red Hat removed the codecs, the encoding and decoding shared libraries, back in September 2002 when Red Hat 8 came out. For the first five years they provided an explanation, you can still find it at archive.org. The decision […]

The installer for Red Hat Enterprise Linux ported faithfully to CentOS, doesn’t give you a lot of control. Or at least not obvious control. You can work around some of the annoyances if you know the right tricks. Let’s look into fixing some of them after the fact. This will be a usefully challenging test […]

A few times now, a student taking Learning Tree’s Linux server administration course has told me that their Linux experience is rather limited. Specifically, that they took the introductory user course about a year ago and they ”haven’t done much since.” Me: ”Uh-oh. So, how much have you used the command line since that course?” […]