How to extend screen to second monitor in Linux / Fedora?

Here's the command that could extend the screen to second monitor, in case Linux does not do the job automatically:

xrandr --output VGA1 --mode 1920x1080 --output eDP1 --mode 1366x768 --left-of VGA1

Where you need to replace the screen size manually. By running xrandr in terminal, you could get the screen size range for each display output.

Beside --left-of, there are other options such as --above, --below, --right-of

[Fedora] Omit GUI and boot with or into command line

Before you start, you need to know what is runlevel.

runlevel is a number that indicates which mode the computer to boot into. For instance, runlevel 5 is graphical mode, where runlevel 3 is text-only mode. Runlevel 1 is single-user mode, commonly used for troubleshooting.

And GRUB (GRand Unified Bootloader), a bootloader which allow you to choose which OS to boot into during computer start up. Here's a screenshot of GRUB.

Now, there are two options:

1. boot with command line, means omit the filling up Fedora logo and show the boot progress by command line
2. boot into command line, means completely omit booting into GUI and end up in command line

What you need to do is at the GRUB screen, select your Fedora OS name and press "e".
Then find rhgb in the line start with linuxefi /vmlinuz. On the right side of rhgb should be word "quiet".

For option 1: Remove the rhgb from the line and press CTRL+X or F10. This should show the command lines as boot progress instead of the Fedora logo. Useful for identifying what has failed during boot progress. The system will still end up in GUI afterwards.

Sample = ... rhgb quiet ... 

For option 2: Here's why you have to understand the runlevel. You achieve this by simply add a runlevel number "3" after the word "quiet" (space in between two words) and press CTRL+X or F10. This should boot the system into CLI instead of GUI.

 Sample = ... rhgb quiet 3 ...

Note:

• rhgb = RedHat Graphical Boot

Terminal does not have history and not showing path?

What happen when a new user's terminal (xterm, lxterminal etc):

1. does not display any path (only show $>)
2. does not support Up key for recall previous command?

It is because the new user is using /bin/sh instead of /bin/bash. To solve this, simply do sudo chsh, then key in /bin/bash when prompted to choose an option.

Restart the terminal then you should be able to get all the features back.

The root cause for this is nothing is specified when the user is being created using command line. Be sure to specify to use /bin/bash to avoid this.

Become Terminal Pro with Shortcuts Keys

Ever want to be proficient with terminal (linux command line)? Then these are the tips & tricks that you must know:

Become a Command Line with These Time-Saving Shorcuts by lifehacker.com
URL: http://lifehacker.com/5743814/become-a-command-line-ninja-with-these-time+saving-shortcuts 

Share this post if the article has made you a pro, have fun!

[Ubuntu] How to disable guest & remote login account in 12.10?

Having the Guest and Remote Login account enabled by default is really not my preference. Personally I think these two accounts should be disabled by default especially privacy is getting more & more important to individual nowadays where most of private files are stored digitally.

I'm not sure why Ubuntu chose to enable them, but if you just hate it like I do, you can disabled them by:

Remove guest account:

sudo /usr/lib/lightdm/lightdm-set-defaults -l false

sudo /usr/lib/lightdm/lightdm-set-defaults --allow-guest false

Remove remote login:

sudo /usr/lib/lightdm/lightdm-set-defaults -R false

sudo /usr/lib/lightdm/lightdm-set-defaults--show-remote-login false

Remove both:

sudo /usr/lib/lightdm/lightdm-set-defaults -l false -R false

sudo /usr/lib/lightdm/lightdm-set-defaults --allow-guest false --show-remote-login false

Do remember to reboot after that.

I have once cannot configure it probably with the full command "--allow-guest" and "--show-remote-login" even without typo error. If you do encounter that, simply use the "-l" and "-R".

[CentOS, Fedora] Yum for novice user

There are a lot to learn about Yum, for novice user below are a few very useful method to get you started with installation using Yum:

• # yum install XXXXX

This command is to install a known program. Normally a program would end with "x86_64" for 64-bit CentOS / Fedora.

• # yum search XXXXX

This is very useful when you know the name of the software, but do not know how the repo name it. Wildcard is not supported here, because no matter what you type, it will treat is a "contain", mean if I search for "fire", I could eventually get "Firefox".

• # yum list XXXXX

List is similar to search, but wildcard is not enabled by default. So if you wanna search for "Firefox", you have to type "fire*".

• # yum groupinstall XXXXX

Group install is very useful not only to resolve dependencies, but it also helps by installing other features that require by particular software. For example, Libre Office, by default installation, it would sometimes not appear in the Application Menu. By doing groupinstall all LibreOffice program will be added to the application menu automatically.

* I have not really dig into the groupinstall behaviour, so might explain wrongly here. To be precise, here's how yum.baseurl.org explained:

Despite their differing names both of these commands perform the same function. They will attempt to install/update all of the packages in the group that are of the types 'default' or 'mandatory' (by default). (To change this types of packages edit the value of the group_package_types option in yum.conf.) And they will install any additional dependencies needed by any of the installing/updating packages.

• # yum update

As the name suggest, this is use to update the system to the latest available patches. Worth to mention here, for those who use Ubuntu / Fedora / CentOS together might get confused a bit, as Ubuntu apt-get update is only to update the repository, but not to perform update to the system. Use apt-get upgrade instead.

I hope this will help many who just start playing around with Yum. Have fun!

[CentOS] Installing CentOS 6.3 Minimal Edition: Part 1

In this post I would list down the steps & tasks I performed after during and after successful installation of CentOS minimal edition.

During Installation
I install CentOS 6.3 in a VM via Oracle VirtualBox. The initial graphic RAM given was 12mb, that has caused CentOS setup fail to boot into a GUI installation. Installing from the old DOS-like environment is headache because somehow it does not show up any available drive for me to select to hold the CentOS.


After a few trials, I decided to re-configured and install in GUI environment. The installation went smooth and very quickly it is done and CentOS is up.

* One thing to take note during the installation is to setup the LAN connection otherwise you would not get connection once boot into CentOS. (Special thanks to Sharuzzaman Ahmat Raslan from Facebook General Linux Discussion M'sia for his advice and screenshot)

To setup the LAN, simply click on the "Configure Network" button on the bottom left.

 

After installation
Once CentOS boot up I'm required to login. Key in root and password (set during installation) then we can start to install everything.

****** This step only required if you forgot to setup LAN during installation ******

Before that I would need to bring up the network interface. I used NAT for the VM. The network interface is not up by default, I did ifconfig and only can see "lo". To bring up the network interface simply type:

# ifup eth0

Run ifconfig to check again and now eth0 has already up and running with DHCP.

****** End of network interface section ******

First thing to do is to perform update to overall system.

# yum update

It is easier and more straight forward to work under GUI than terminal mode. So I decided to install the Gnome Desktop Environment & KDE. The reason I install both because there are some KDE tools & programs are useful to me. Before we can install Gnome/KDE, we must first install the "X Windows System". Yum has an option to do groupinstall. It will help you resolve all dependencies, for novice users this come in very handy. Execute the following:

# yum groupinstall -y 'X Window System'

So what is mean by "-y" in the command line above? It means "answer yes to all", so the system will perform every resolved dependencies without getting further permission from me.

To install Gnome, execute:

# yum groupinstall -y 'Desktop'

* A reminder here: Restart is not required after install "X Window System". If one restarts the system, remember to bring up eth0 again.

Once the installation done, execute:

# startx

I'm now in the Gnome Desktop environment. To make sure it run every time we restart the system, simply go /etc/inittab and change the id:3:initdefault: to id:5:initdefault:.

* To change and save the inittab file, we can use:

# vi innittab

press "Insert" on keyboard to enter editing mode. Once done, press ESC and type ":wq".

Reboot with command init 6 and I can now work in desktop environment.

===============================
There are some issue with minimal edition of CentOS that is it comes with very limited tools we can use to configure the OS. The most critical stuff that are missing is text editor such as gEdit / Kedit / Leafpad. Personally I prefer Leafpad, but to install Leafpad it is not as straight forward.

Some other issue:

1. the network interface is not configure to load automatically when OS starts
2. Mozilla Firefox is not pre-install

I will cover in Part 2 how to install those missing stuff as well as configure the network interface so it loads with the system.

Until then, have fun with your newly installed CentOS!

===============================
Some useful links for reference:

• Yum introduction: http://yum.baseurl.org/wiki/YumGroups
• Yum maintenance: http://www.centos.org/docs/5/html/yum/sn-yum-maintenance.html
• Automatic update and retrieval and installation: http://www.cyberciti.biz/faq/fedora-automatic-update-retrieval-installation-with-cron/

Run application standalone from terminal with root permission

If you get tired having to turn on many terminal so to run multiple application with root permission, try to add a "&" symbol after the name of application.

This will enable the application to run standalone from the terminal and you can continue to work on the same terminal.