rickogden.com » bash

Arithmetic in Bash

Rick Ogden — Wed, 23 Dec 2009 11:33:29 +0000

Bash is not exactly brilliant at performing numerical calculations. Recently I’ve required the need to see how many people are currently logged in on the terminal servers through NX. Now, if people are logged in via standard SSH, then it’s quite easy to count:

who | wc -l

However, if you want to perform a line count of the NX list, you have 6 lines at the top which are not part of the count. In order to perform this subtraction, we need to do a calculation. To do this in bash we use a $(()):

echo $((2 + 2))

So, if we were to use this when performing the command on nxserver, this is how it would look in the end:

echo $(($(/usr/NX/bin/nxserver --list | wc -l) - 6))

Or, if you’re not running this script as root (and using sudo):

echo $(($(sudo /usr/NX/bin/nxserver --list | wc -l) - 6))

Updated Ubuntu FreeNX Install Script

Rick Ogden — Wed, 18 Nov 2009 09:27:30 +0000

I’ve just updated the FreeNX install script to download and install the latest version of the NX Client from NoMachine. If you have used the previous version of this script, then you can just execute this version and it will automatically update your NX Client.

Download the latest version from here.

FreeNX Installation Script for Ubuntu

Rick Ogden — Mon, 02 Nov 2009 12:31:49 +0000

I have introduced a Labs section to my site. This section will contain on going projects, applications and scripts which I am working on for people to play with a leave feedback.

At the same time I have added a script to the section, which automatically downloads and installs FreeNX onto an Ubuntu system. The script and further details are available from here.