19

Mar

2016

Batch Auto-Levels on Images

March 19, 2016 jonny photography, shell

I had a thousand image files the kids had photographed when creating a stop motion video. An 'auto-levels' on many of the images was required to brighten them up so at the command line I used the following (with ImageMagick already installed of... » More

02

Jan

2016

Customise Yakuake Tabs On Start

January 2, 2016 jonny ubuntu

I've been recommending the slide-down terminal Yakuake to people for some time now and I couldn't live without it myself. Although I use Cinnamon as a desktop I much prefer Yakuake over Guake and can live with the extra RAM usage of the KDE... » More

01

Jan

2016

Bleeding Edge PHP on CentOS 7

January 1, 2016 jonny php, red hat centos

The PHP packages in the base / epel repositories are very conservative. To opt for something more current the REMI repo can be used. Install the remi-release package (info)  first: wget... » More

30

Dec

2015

Discourse CentOS – which: no docker.io in

December 30, 2015 jonny red hat centos

This must be my second or third attempt at Discourse having given up several times before and I may well find reasons to avoid it again. The Discourse advice of just use Ubuntu or using DigitalOcean doesn't cut it for me. One of the problems I ran... » More

29

Dec

2015

Arduino Serial Port Menu Greyed Out

December 29, 2015 jonny ubuntu

On Linux Mint (Ubuntu) I had installed the Arduino IDE from the repository and that had installed version 1.0.5. Despite setting the permissions on the Arduino USB device, the 'Serial Port' option in the IDE menu was greyed out and would not allow for... » More

26

Dec

2015

Resetting Drained Slurm Node

December 26, 2015 jonny red hat centos

After barking up the wrong tree for a while I discovered via StackExchange how to reset a Slurm Node reporting as drained. Run the scontrol command then update the node as shown in the following example commands (amend the word jacob here to the name... » More

16

Oct

2015

MySQL GRANT SELECT on a demo database to all users

October 16, 2015 jonny mysql

I needed to give all students read access to a demo database and did so with: mysql> GRANT SELECT ON gameofthrones.* TO ''@localhost; Query OK, 0 rows affected (0.00 sec) mysql> FLUSH PRIVILEGES; Query OK, 0 rows affected (0.01... » More

08

Oct

2015

Kerberos Keytab File Creation on Ubuntu

October 8, 2015 jonny ubuntu

To create a kerberos keytab file on Ubuntu and with the kerberos packages installed (e.g. sudo apt-get install krb5-user ) root@jmcc02:~# ktutil ktutil: addent -password -p myusername@DOMAIN.TLD.COM -k 1 -e RC4-HMAC Password for... » More

05

Oct

2015

Apache: unable to open logs

October 5, 2015 jonny apache, linux

In the annals of "Everyday is a learning day". I have an Apache server hosting student websites, and the number of websites grew to over 700 within a day and Apache was complaining with error: unable to open logs It took a little while to narrow down... » More

21

Sep

2015

Customise the Unity Launcher from Command Line

September 21, 2015 jonny ubuntu

I am rolling out some Linux desktops, specifically Ubuntu, and I wanted to customize the icons available in the Unity Launcher. I wanted to remove the LibreOffce Calc and Impress icons and the darned 'Amazon' one, so: Create a new gschema override... » More