In this tutorial we will look through how to package some simple hello world script.
A quote from debian maintainer's guide:
One thing is certain, though: to properly create and maintain Debian packages takes many hours. Make no mistake, for our system to work the maintainers need to be both technically competent and diligent.
We have many methods to create a Debian package In this tutorial we will use FPM.
This method requires minimum effort follow this if you don't want to upload to PPA. However it requires ruby gem and package name FPM. check wiki for further details.
mkdir -p ~/via-fpm/debian/usr/bin/
Add following lines to script.
echo "hello debian packaging via fpm"
Save and close that file.
whatever folder structure you will put in your source folder it will automatically copied into respected folders. There is no need to to copy them. For example if you want to put some sources file in /opt/local/sources then you must have same structure in you application source.
Similarly usr/bin/ files will automatically copied to their respected folder in this case that will be /usr/bin.
Next we will come towards the scripts that will automatically run like preinstall , post install , pre un-install and post un-install . If you want to create user, directories, set permissions then these scrips are for you. You can use bash here.
In this demo we will use "postinst" script to set permission for ~/via-fpm/debian/usr/bin/hello-via-fpm.sh
create postint file in described location and add the following code.
sudo chmod +x ~/via-fpm/debian/usr/bin/hello-via-fpm.sh
It't time for packaging.
fpm --epoch 1 -s dir -e -C debian \
-a all -m "uncle demo <UncleDemo@example.com>" \
--description "our absurd debian package for demo via fpm" \
-v 1.0 -t deb -n hello-via-fpm --after-install debian/opt/local/postinst
Switches that we have used and their meaning
-epoch: Used for epoch value is somehow versioning number
-e: Edit the package spec before building. (default: false)
-C: Change directory to here before searching for files
-a: The architecture name. Usually matches 'uname -m'. For automatic values, you can use '-a all' or '-a: native'. These two strings will be translated into the correct value for your platform and target package type.
-m: The maintainer of this package. (default: "djhaskin987@djhaskin987-S301LA")
--description: add description
-v: specify version number
-t: output type
-n: Name to give to the package
--after-install: file to run after post install
Because it will automatically create necessary files like control, rules and lot other necessary stuff for you. There are other proper ways to do that using official Debian package management through which you can upload your package to PPA. That we will discuss in next demo.
To install that package either open via Ubuntu software center or run command sudo dpkg -i hello-via-fpm_1.0_all.deb
Now try to run command from shell hello-via-fpm.sh to see that your package is installed now and further you can create your own with customizations.
The latest version of LibreOffice is here but unfortunately its not going to be available in Ubuntu 14.04 and 12.04 by default. But the good news is that we can upgrade existing version by typing these commands:
Ubuntu has a special account, named Guest, which allows access (login) to the system without asking for any password. Although there are limitation applied to this account but maybe its not always desirable to have it. These steps will help in disabling it (tested under 12.04):
Open the file /etc/lightdm/lightdm.conf and add the following line to it at the end:
Today I was installing Ubuntu in my Olives School lab. There are 20 systems in total. After installing it in the first PC, I ran the Update and there were 443 of them which amounted for 337MB approx. As it can be imagined it took some time to get the first PC updated. This was clearly not what I was going to do with the rest and I had to come up with a solution.
When Ubuntu downloads these updates, it places them in /var/cache/apt/archives/ folder. In fact even after installing updates, they are not removed from the system. So a solution was simple:
Copy all the downloaded packages to a USB
On the next PC, run the command:
sudo cp [path-to-usb]/* /var/cache/apt/archives
Once all the files have been pasted, run the Update Manager tool and it will tell you that updates have been
downloaded but not yet installed.
In an earlier post, I mentioned about the Runlevels in Ubuntu and how its different from the rest of the Linux family. Each Runlevel can be configured to start with certain services. A tool to manage the Services in Ubuntu is sysv-rc-config
This tool can be installed using the command:
sudo apt-get install sysv-rc-conf
Once installed, it can be used as:
This tool will display all the services and the runlevels. You can easily choose which services to load and which not to. The screenshot shows how it will appear. To exit the tool, press q key.
Although I am not a fan of Internet Explorer but sometimes it cannot be ignored especially when few websites have limited their access to IE browsers only or some old websites with poor markup which only renders on IE.
Internet Explorer (IE 5, 5.5, 6 and 7) can be installed and run on any Linux distribution. The package can be found and downloaded from these links:
When installing IEs4Linux, the Linux X-Window may crash, giving you the following error message:
The program ‘ies4linux-gtk.py’ received an X Window System error.
This probably reflects a bug in the program.
The error was ‘RenderBadPicture (invalid Picture parameter)’.
(Details: serial 5546 error_code 158 request_code 148 minor_code 7)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the –sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)
The workaround this is to use the non-GUI, command based installation. To install use the command:
For further help:
I hope the day comes when all of this is not required and we have a true cross-browser web.
When we download video from Youtube or any other website, 90% chances are you are watching them using Flash Video Player whose format is FLV. Some of the videos uploaded in Youtube are sliced into multiple parts especially when Youtube only allowed you to upload a video of maximum 10 minute duration.
There is a simple but useful way of joining these files into a single under Ubuntu.
First you will need to install the package:
sudo apt-get install avidemux
Next, keeping the audio/video encoding unchanged, just join them (change the filenames accordingly):
Sometimes Google Chrome under Linux or Ubuntu gives the following error:
Your preferences can not be read.
Some features may be unavailable and changes to preferences won’t be saved.
This is because the owner of the following files have been changed for some unknown reason:
Under /home/[user]/.config/google-chrome/ the file Locale State and under /home/[user]/.config/google-chrome/Default the file Preferences.
Note: This tip works for Linux, for Windows the steps have not been personally tested.
If you are using Windows XP:
C:\Documents and Settings\[Username]\Local Settings\Application Data\Google\Chrome\User Data\Default
Mounting ISO files in Linux is quite straight forward and simple e.g. using the mounter function in Ubuntu straight from the context menu or by using a command line like this:
mount -o loop image.iso /mnt
Anyway mounting BIN/CUE image files is not that straight forward as they’ll need conversion to ISO before mounting, however the process is quite simple, but it need a small application called bchunk. The bchunk package contains a UNIX/C rewrite of the BinChunker program. It converts a CD image in a .bin/.cue format (sometimes .raw/.cue) into a set of .iso and .cdr/.wav tracks. The .bin/.cue format is used by some non-UNIX CD-writing software, but is not supported on most other CD-writing programs.
Runlevel is the mode in which the operating system like Linux is running. Conventionally, seven runlevels from 0 to 6 existed. Where 0 meant shutdown and 6 meant Reboot.
In previous versions, Ubuntu used to the /etc/inittab file to manage runlevels, just like most of the Linux distributions. This file was based on traditional init daemon, which is used to perform system startup tasks. This was replaced in Ubuntu 6.10 (Release date: 26th-Oct-2006) with Upstart, an event based daemon. Now there are several files under the /etc/events.d/ directory.