The grep command is a command that most Linux users learn early on, and many times they learn to use it via pipes (stdin). Because of this some Linux users just assume that grep can only be used with stdin; it's ok, I was one of those too! Before I continue with some grep tricks I want to clarify the basic grep usage. Stop Doing This: $ cat file.log | grep "something" something Do This More:...
Are you tired of trying to memorize tons of passwords on different systems? Or do you simply want to have a faceless user SSH between two systems without being asked for a password? Well you are in luck because today we will be covering SSH keys. SSH Servers have the ability to authenticate users using public/private keys. In the case of pass-phrase less keys this allows users to ssh from one system to another without typing a password....
One of the most basic tasks for any Sysadmin is packing and unpacking files for various reasons. While there are many ways to perform this task GNU Tar is probably one of the most recognized and commonly used tools by Linux/Unix users. A little history on tar The tar command is a command that appeared in the early days of Unix and has had several changes made over time. Originally the command was used to take files, combine them into one file and write them to a tape archive (tar)....
Normally on this blog I tend to write about more complicated tasks or fancy Linux tricks and completely overlook some of the most basic tasks that a SysAdmin needs to know. Today I have decided that I will make my blog a little more comprehensive and add some posts with some of the basics. Along with this I will be starting a new category, called Sysadmin Basics and I will try to post an additional article each week that covers some of the more basic concepts and commands used by Linux and Unix Sysadmins....
Recently I have been playing with the Global Parallel File System, which is a clustered file system from IBM. When setting up a cluster you can configure GPFS to utilize SSH/SCP to send administrative tasks to the other nodes in the cluster. The problem I ran into was that in my environment I do not run SSH over port 22 (for various reasons I wont get into). Needless to say once I configured SSH to listen on an alternate port GPFS stopped working....