Multiply floats by 10,100, … in bash

A short one today. Bash can only handle integer numbers and not floats, so when someone searches the internet on how to use math on floats in bash the solution they find is usually “use bc” and looks something like this:

Or if they want the result to be an integer:

It’s a […]

Convert configuration files to ansible templates

I’ve been playing around with ansible a lot lately, and I noticed that while changing stuff from “installed and configured manually” to “installed and configured by ansible” I was running into quite a few configuration files that needed to be manually turned into templates. It can be quite tedious to replace values in a configuration file with […]

How to install the latest Nmap for Debian/Ubuntu

A quick & dirty script to download the latest version of nmap (sourcecode) and generate a deb and install it (so that it’s correctly in the package management). Yes, I know this is not much more than a glorified configure && make && checkinstall

Simple “try” function for bash

Made a nice little try() function today for simplifying checking/dealing with  return codes from commands. It uses the function text() I posted earlier to colorfy output: How to easily add colored text output in bash scripts. The function accepts 2 parameters, how it should behave if a problem occurs and the command to be executed: try <silent|warn|fatal> command […]

How to get the intersecting area of two polygons in MySQL

I was playing around with spatial features of MySQL this weekend and stumbled into a problem where I was looking for the area of two rectangles that overlap.  MySQL provides a function to check if they overlap, but no function to extract the region that overlaps. I’ve never written a stored routine in MySQL before, […]

How to increase Fraps performance with a ramdisk

I recently started playing Battlefield 3 and remembered that I have a Fraps license so I installed it and started recording some stuff. Unsurprisingly the performance made a big dip when I recorded. A glance at my PC told me the harddrive was at fault, probably bringing the whole system down due to IO. Since my PC […]

How to easily add colored text output in bash scripts

Here is small snippet that can give your shell scripts some nice output: colortext.sh As with the debug.sh script, just download it to the same directory as your own script and add it with

It contains one simple function called text with the syntax text “text to be output”. Color can be red, green, yellow, […]

MySQL selecting IPs via CIDR

Quick little snippet here for selecting IPs from a database based off a CIDR subnet. First off a table structure with some test data:

Now let’s say we want all IPs from the subnet 173.192.175.16/28, using a simple 173.192.175.% would provide false results since you don’t want the whole /24. If your IP is […]