Dynamic shell prompt

Dynamic shell prompt can change it's form according to some events going on on terminal. It can change e.g. color, if the previous command execution was unsuccessful, or it can display various information.
In this post, there is an example of such a prompt. It displays information, when you enter specified working directory.

The picture below shows my configuration:

This is achieved with setting a variable PROMPT_COMMAND which is evaluated every time you run a command. In my case, there is a condition, which looks for matching path.

# dynamic PS prompt
export PROMPT_COMMAND='PS1="$(if [ "$(pwd | grep /mnt/storage/backup_git)" ]; then echo "\\[\\033[32m\\]backup_git "; fi;)\[\033[01;31m\]\h\[\033[01;34m\] \W \$\[\033[00m\] "'

HA-HeartBeat on Raspberry PI

High Availability HeartBeat is a clustering daemon. It allows to setup virtual IP addresses on network interfaces in order to provide redundancy in service availability. (It can also be used to automatically start/stop services)
In this post, we take a look at the basic HA usage, with two nodes.

mpd console player and ncmpcpp

For long time I've searched for a good music player. I've settled with mpd (music player daemon) and as a graphical frontend I use ncmpcpp. This post shows how to install and configure mpd and ncmpcpp.

i3wm: change QT/GTK theme

If you'd like to change your window appearance, you can use systemsettings utility for QT windows and .gtkrc conf for GTK windows.

systemsettings is part of the KDE (included in kdebase-workspace package). Navigate to Application Appearance to change window theme:

GPIO 05-pwm

Raspberry PI has the ability to use PWM (pulse width modulation) to control width of the pulse sent on the GPIO pin, which provides better granularity to control connected devices, in this case LED.
This feature allows to control LEDs intensity, which can be used with RGB LED to mix colors.

GPIO 04-rgb

I finally got to the RGB LED and tried to connect it to Raspberry PI.
This first script (04-rgb.sh) is a modification of previous one. It uses one new feature though, associative fields in bash to distinguish between the three basic colors (RGB) and their combinations (Yellow, Purple, Light Blue, White) as shown on the figure:

The following figure shows how the LED is connected to GPIO.

owncloud: Authentication error

This issue has been bothering me from version 5. After some investigation, it turned out the owncloud's authentication was "compromised" by other services running on the same web server (nginx) using the same fastcgi processor.