Archive for the ‘ubuntu’ Category

execute a command during boot as root

During the boot process you want to execute a command as root. For instance, I needed a symbolic link in /run, but /run is a virtual file system and its content is lost when you switch the machine off.

Edit the file /etc/rc.local . Example:

#!/bin/sh -e
# rc.local
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
# In order to enable or disable this script just change the execution
# bits.
# By default this script does nothing.

# this link is required by a project of mine
ln -s /media /run/media

exit 0

This tip is from here.

Categories: ubuntu Tags: ,

Getting started with the Rust programming language

December 24, 2014 Leave a comment

I heard a lot of good things about Mozilla’s Rust prog. language, so I decided to give it a try. A very nice starting point is The Rust Guide.


$ curl -s | sudo sh

I modified this script a little bit:



cd $DEST
rm -f $DEST/
wget -O $DEST/
sudo sh $DEST/

But it does the same thing. If you install Rust via this script, it has two advantages: (1) it installs the latest version of Rust, and (2) it also installs Cargo, the package manager and build system of Rust.

Print the version number: “rustc -V“.

Hello World

fn main() {
    println!("Hello, World!");

Compile it with “rustc“.

Under Ubuntu I had no problems, but under Manjaro got the following error: “rustc: error while loading shared libraries: cannot open shared object file: No such file or directory“.

Solution #1
Add the following line to your ~/.bashrc:

export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/usr/local/lib

Solution #2
Create the file /etc/ with the following content:


Then execute the command “ldconfig” as root.

More info
Check out The Rust Guide.

Categories: manjaro, programming language, ubuntu Tags:

extracting conky settings from Parted Magic

December 19, 2014 Leave a comment

Two days ago I heard about Parted Magic, which is a live Linux CD offering a complete hard disk management solution. As I was checking out the screenshots, I noticed that it has a beautiful conky setting:

“I need that” was my first reaction :) So I grabbed a copy of Parted Magic, launched it in VirtualBox, and extracted the conky configuration. You can download it from here. My launcher script is here. Simply add the launcher to the list of startup applications.

Tip: if you want to play with conky, do it with Conky Manager. Here is how to install it.

shopt: change additional shell optional behavior

November 22, 2014 1 comment

There is a command called shopt that allows you to change additional shell optional behavior.

I use both Ubuntu and Manjaro and I noticed that sometimes bash behaved differently on Manjaro. For instance, I had a folder called “Test_me”. Once accidentally I wrote “cd test_me” and Manjaro entered the folder “Test_me” (notice the capital ‘T’) without any problem. Under Ubuntu it was impossible :)

As it turned out, the different behaviour is due to different shopt settings. In the example above, “cdspell” was on in Manjaro, while in Ubuntu it was off by default.

Since I use both systems and I want bash to behave similarly, I added these lines to the end of my ~/.bashrc:

# shopt settings (normalize Ubuntu and Manjaro)
shopt -s cdspell
shopt -s dotglob
shopt -s hostcomplete
shopt -s nocaseglob
shopt -u sourcepath

I switched “sourcepath” off. Read this post if you want to know why.

Categories: bash, manjaro, ubuntu Tags: ,

detect easily if your machine is frozen

October 6, 2014 Leave a comment

Very rarely my system gets frozen. But is it just my keyboard and mouse that have problems? Or is my whole machine frozen? Or is it just temporary and everything will be normal in a few seconds?

I have an easy solution to detect if the whole system is frozen. In the top right corner you have a clock, right? Well, add seconds too :) If the seconds are stuck, there is a problem. If they are moving, there is still hope.


Update (20141014)
Yesterday my machine got frozen quite interestingly. I got an email with a youtube link that I wanted to play in Gmail. The machine got frozen, i.e. the mouse/keyboard had no effect and the clock didn’t move BUT the audio of the video was rolling :) I could do nothing but listen to it. At the end I had to restart the machine manually. Lesson learned: even if the clock is stuck, it doesn’t mean that your machine is completely frozen. (I guess this all happened because of Flash).

Categories: ubuntu Tags: ,

Firefox is started automatically but it looks corrupted

September 28, 2014 Leave a comment

On my home desktop I have autologin enabled, i.e. I don’t need to log in manually. Since I always need a terminal and a browser, “konsole” and “firefox” are started automatically. So I just switch on my machine and when I come back 5 minutes later, I’m ready to work.

However, sometimes Firefox doesn’t start normally. It looks strange: some colors are replaced with a different one, fonts are different, tooltips on tabs are plain black (text in tooltips is not visible), etc. If I restart Firefox, it becomes OK. I’m not sure what causes this problem, but my guess is that Firefox is started too quickly. I think it would require some libraries that are not yet loaded when Firefox is started. Then these pieces of software are loaded, that’s why Firefox gets OK after a restart.

The solution is simple. Don’t start Firefox immediately after the login. Wait some time until everything else is loaded, and start it after. Of course, we still want to start Firefox automatically, not manually. So we need a simple script:

#!/usr/bin/env bash

# /home/jabba/bin/
sleep 60    # Wait 60 seconds. You can play with this value.
/usr/bin/firefox &

Then in the Startup Applications, remove “firefox” and add this script instead. Provide the absolute path of the script. Make sure it’s executable. Here is a screenshot of the applications that are started automatically on my machine:


Categories: firefox, ubuntu

Launch gedit in the background

September 11, 2014 1 comment

Sometimes I use gedit but it is launched in the foreground, blocking my terminal. There are two ways to put it in the background: (1) Press CTRL+Z in the terminal, then send the job to the background with the command bg, or (2) launch gedit directly in the background with the “&” sign.

Neither of them is convenient. I often forget about it and I always end up in a blocked terminal. I just simply want to write “gedit” or “gedit ehh.txt“, and I want it to start in the background.

Create a script called “gedit” in your $HOME/bin directory with the following content:

/usr/bin/gedit "$@" &

Make it executable and make sure the directory $HOME/bin is in your PATH.

Categories: bash, ubuntu Tags: ,

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