Technology Insights

Htop Exclamation Mark Near Uptime In Output On Linux Server

The other day while troubleshooting an issue on a server I noticed something I hadn’t ever noticed before which was an exclamation mark next to the uptime output from the htop command. After investigating and looking over the source I found that it is a bonus letting you know that your server has been up for a long time. Basically anything over 100 days of uptime will produce an exclamation mark next to the uptime reading. Below I show the sourcecode from the UptimeMeter.c file in the htop source as well as examples of how the htop uptime can vary depending on how long your server has actually been up.

Technology Insights

How to Install MacPorts on Snow Leopard 10.6

I have recently gotten a macbook pro to play around with so my next few articles will most likely cover getting the tools and such the way I want them on the mac book pro. The first thing I discovered is that many of the command line tools which I use every day such as nmap are available in the macports package which is a package management system similar to what I was used to in Linux.

I will details the steps I had to take to get macports installed:

Technology Insights

CentOS Linux: sort: invalid option — R, Try sort –help for more information

I was working on an article a couple days ago with a friend and he had sent over some commands for me to reference in the article which included the “sort -R” command. The sort -R switch will randomly sort the contents of a file which is very useful in certain situations. The problem is that the sort command which is installed by the coreutils RPM package on CentOS does not include the -R switch because it is to old. Below I describe the issue in more detail and provide references on how you could upgrade sort on CentOS Linux.

Technology Insights

How to Make a Patch using Diff

I have had a lot of questions lately about making patches. On Backtrack we get a lot of user submissions and many times we need a patch rather than a modified source file. The reason being is that a patch can be documented and contains the specific changes made to the source file and can also be easily reverted. Patching is also crucial if you fix a bug in a program and would like to submit the fix to the author. In any case being able to create a patch is very  useful if you are working with Linux or any sort of programing stuff.

I decided to make a short post on how to make a patch and apply it:

Technology Insights

Compile John the Ripper on x86-64 Cent OS with the Jumbo Patch

I am getting ready for a password contest at Defcon that Alex and I and a few other guys from the Hashcat team are going to enter and I decided to install John the Ripper on a Cent OS box in case I needed it for anything. John is in the yum repos however the version is pretty old and it is not compiled with NTLM support so I decided to build it from source so that i could apply the Jumbo patch which adds support for a whole lot of different algorithms which are normally only available in the pro version of John the Ripper.

Below I show the steps I took to get it compiled and working on Cent OS 64 bit: