I normally write about Windows, network, smartphones and a lot of other tech stuff, but for some reason I have never posted about Linux before. Recently I needed to refresh my Linux skills because I needed to work with a phone system based on Linux. I have not used Linux much for the last 10 years, but it still pops up from time to time and I am glad that I got some basic knowledge about it, because it helps me understand other system based on Linux.
Who use Linux these days?
Well the simple question to that is that most people does. In fact, I think you are in touch with Linux in some way, every single day. The thing is that many blogs and websites are running on a Linux webserver, including most WordPress blogs like this one. The Android OS used in many smartphone and tablets are running on a Linux kernel underneath. VMware servers are also running on some kind of Linux kernel and a lot of mail servers are also running on Linux. The main reason for that is that Linux is free and very reliable
Linux Tips to get you started
Now that you got a bit of background information about Linux let get started with some tips and tricks to get you started working with Linux. On order to write this post, I downloaded and installed a CentOS (Red Hat) distribution from the official website. CentOS is Open Source software and by that free for you to install.
When you install your CentOS system, it will, by default boot up in the graphic X Window System just called X. This might be good for you if you have only worked with Microsoft Windows or Mac OS and ain’t used to do everything from a command prompt. However if you want to change the way your CentOS system starts up you should take a look at Run Levels. Let us have a look at the file /etc/inittab. This file show us the available runlevels and the last line tell us what the current runlevel is when we boot the system (id:5:initdefault)
# Default runlevel. The runlevels used are:
# 0 – halt (Do NOT set initdefault to this)
# 1 – Single user mode
# 2 – Multiuser, without NFS (The same as 3, if you do not have networking)
# 3 – Full multiuser mode
# 4 – unused
# 5 – X11
# 6 – reboot (Do NOT set initdefault to this)
As you can see the default level id set to ID:5 which mean that the system will boot to X11 (Graphic mode). If you want to change this, you will have to change the last line of /etc/inittab. E.g. if you want it to boot to a command prompt you should change it to id:3:initdefailt:
If you want to change run level just once, but keep the standard boot option level you can use the command init followed by the level you want to switch to (0-6).
E.g. The following command will change your server to boot to runlevel 1 (Single user mode):
Change keyboard language
Another thing you might want to change on your installation is the keyboard language, unless you live in the US of cause. In my case, I wanted to change the language to Danish. To do that I went to the file: /etc/sysconfig/keybord
I changed the KEYTABLE to dk-latin1 and LAYOUT to dk:
To figure out what the correct values is for your language, go to the /lib/kbd/keymaps/i386/qwerty/ folder to find the correct language files. If you e.g. want to change your language to Norwegian, your keyboard file should look like this:
Using the manual command
One of the thing I like most working with Linux is that the help is never far away. If you need help to use a Linux command, all you need is to write man in front of it and it will present you for help and examples with the command. E.g. try to enter: man init to get help with the init command. You will be presented with one page at the time and can move on hitting the space key for each page. If you want to return to the prompt, simply just hit the ‘q’ key.
The Nano Editor
The Nano editor is an easy to use editor. It is much easier to use then the more common VI editor that might be able to do some advanced tasks, but is very difficult to get started with. I will highly recommend you to use the Nano editor, if you are new to Linux. Simply just type nano to start the editor or eg. “nano /etc/sysconfig/keybord” to edit the keyboard file we disgust in one of the above sections.
TOP – Linux Performance Monitor
One thing that can be difficult in Linux is to monitor performance. When most of the system run as services and there is no graphic user interface, how do we figure out what process is killing our system? The first thing I will recommend you to do is to have a look at the top command. Simply type top and hit return and you will see screen like the one below. It will refresh automatically and you can quit at any time hitting the ‘q’ key.
I will stop this post for now. I am sure that you can find a lot of other great Linux guides and resources available online. If you are new to Linux all this might seems very difficult to use, but if you start figuring out the small things, you might find it very useful and want to learn more about it.