Setting process CPU priority with nice and renice

Nice is a command in Unix and Linux operating systems that allows for the adjustment of the “Niceness” value of processes. Adjusting the “niceness” value of processes allows for setting an advised CPU priority that the kernel's scheduler will use to determine which processes get more or less CPU time. In Linux this niceness value can be ignored by the scheduler, however other Unix implementations can treat this differently. Being able to adjust the niceness value comes in handy in two scenarios usually....

 · 4 min · Benjamin Cane

Removing Files and Directories with rm and rmdir

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....

 · 4 min · Benjamin Cane

10 nmap Commands Every Sysadmin Should Know

Recently I was compiling a list of Linux commands that every sysadmin should know. One of the first commands that came to mind was nmap. nmap is a powerful network scanner used to identify systems and services. nmap was originally developed with network security in mind, it is a tool that was designed to find vulnerabilities within a network. nmap is more than just a simple port scanner though, you can use nmap to find specific versions of services, certain OS types, or even find that pesky printer someone put on your network without telling you....

 · 8 min · Benjamin Cane

Mitigating DoS Attacks with a null (or Blackhole) Route on Linux

In a world where the Anonymous group is petitioning the US Government to make DDoS attacks a legal means of protest; For internet facing systems the threat of Denial of Service attacks are very real. The cold harsh reality of DoS attacks are that there is no way to stop them. While there are services out there that are designed to take the brunt of the attack for you these costs a significant amount of money (update: CloudFlare seems pretty decent)....

 · 3 min · Benjamin Cane

Cheat Sheet: Cutting Text with cut

The cut command is a Unix/Linux tool used to literally cut text from files and output from other commands. With the cut command a user can take text and output only certain parts of the line. In my opinion cut is the most under recognized and utilized command in Linux/Unix. This is mostly due to the fact that when most Sysadmins want to cut text from files or standard output many will reach for AWK....

 · 3 min · Benjamin Cane