Category: Ubuntu

Linux system administrators need to configure networking on their systems. On desktop machines, you can use dynamic IP addresses but on server infrastructure, you will need to set up a static IP address for a stable connection.

IP addresses on Linux systems are mostly assigned automatically by Dynamic Host Configuration Protocol (DHCP) servers. These are referred to as “dynamic addresses” and can change any time the system is rebooted. When a system is on a server or will be remotely administered, it is more convenient for these systems to have static addresses, offering stable and consistent connections with users and applications.

Fortunately, the steps required to setup a Linux system’s IP address from dynamic to static are fairly easy, though they will be a little different for the various distribution you are using. In this post, we’ll look at how this task is managed on RHEL/CentOS/Fedora and Debian/Ubuntu systems.

IP address: 192.168.0.100 Netmask: 255.255.255.0 Hostname: node01.linux-documentation.com Domain name: linux-documentation.com Gateway: 192.168.0.1 DNS Server1: 8.8.8.8 DNS Server2: 4.4.4.4

Configure Static IP Address in RHEL/CentOS/Fedora:

To configure the static IP address in RHEL / CentOS / Fedora, you will need to edit these files:

/etc/sysconfig/network
/etc/sysconfig/network-scripts/ifcfg-eth0

Where in the above "ifcfg-eth0" answers to your network interface namedeth0. If your interface is named “eth1" then the file that you have to edit is "ifcfg-eth1".

Let’s start editing the first file:

# vi /etc/sysconfig/network

Open that file and set the following:

NETWORKING=yes HOSTNAME=node01.linux-documentation.com GATEWAY=192.168.0.1 NETWORKING_IPV6=no IPV6INIT=no 

Now open next file as shown below:

# vi /etc/sysconfig/network-scripts/ifcfg-eth0

Note: Make sure that you have opened the file corresponding to your network interface. You can get your network interface name using command ifconfig -a.

In that file you have to make the following changes:

DEVICE="eth0" BOOTPROTO="static" DNS1="8.8.8.8" DNS2="4.4.4.4" GATEWAY="192.168.0.1" HOSTNAME="node01.linux-documentation.com" HWADDR="00:19:99:A4:46:AB" IPADDR="192.68.0.100" NETMASK="255.255.255.0" NM_CONTROLLED="yes" ONBOOT="yes" TYPE="Ethernet" UUID="8105c095-799b-4f5a-a445-c6d7c3681f07"

You will only need to edit the settings for i.e enter their respective values and save the file:

  1. DNS1 and DNS2
  2. GATEWAY
  3. HOSTNAME
  4. NETMASK
  5. IPADDR

Other settings should have already been predefined.

Next edit resolve.conf file by opening it with a text editor like nano or vi:

# vi /etc/resolv.conf
  
nameserver 8.8.8.8 # Replace with your nameserver ip
nameserver 4.4.4.4 # Replace with your nameserver ip

Once you have made your changes restart the networking with the following commands:

# /etc/init.d/network restart  [On SysVinit] 
# systemctl restart network [On SystemD]

Set Static IP Address in Debian / Ubuntu

To setup static IP address in DebianUbuntu, you have to open the following file:

# nano /etc/network/interfaces

You will see a line looking like this:

auto eth0
iface eth0 inet dhcp

Change it so it looks like this:

auto eth0
iface eth0 inet static 
  address 192.168.0.100
  netmask 255.255.255.0
  gateway 192.168.0.1
  dns-nameservers 4.4.4.4
  dns-nameservers 8.8.8.8

Save the file and then edit /etc/resolv.conf as follows:

# nano /etc/resolv.conf
nameserver 8.8.8.8 # Replace with your nameserver ip 
nameserver 4.4.4.4 # Replace with your nameserver ip

Restart the networking on your system with the following commands:

# /etc/init.d/network restart  [On SysVinit]
# systemctl restart network [On SystemD]

Your static IP address has been successfully configured.

Now, you know how to configure a static IP address on a Linux distro.

An Overview of Ubuntu and Fedora

Both Ubuntu and Fedora are Linux distributions. Ubuntu is developed by Canonical Ltd. and is based on Debian while Fedora is developed by  Fedora Project which is sponsored by Red Hat. Both operating systems are free and open-source software. Now that you have read the introduction to the OS let’s move on to the comparison of Ubuntu and Fedora.

Comparison

Latest technology integration: When it comes to the latest technology Fedora is unmatched. Although Ubuntu also strives to integrate latest technology, Fedora is just faster at it. Fedora claims to be a bleeding-edge operating system. It means that it provides frequent changes as technology progresses which might have some downfalls as explained later.

Stability: When it comes to stability Ubuntu is more stable than Fedora and the reason for that is the priorities of the two organizations. As mentioned above Fedora is an operating system that aims to provide you with the newest software faster than others. Contrary to which Ubuntu aims for stability. That is the reason why Ubuntu falls a bit behind in providing such technology as before any such update is released the developers make sure that it is totally stable, and they take their time in doing so. However, it doesn’t mean that Fedora is unstable. It is just that since it has to provide updates faster sometimes it may have bugs.

Frequency of updates: Fedora has more frequent updates than Ubuntu. This feature has its pros and cons. The advantage that you get from frequent updates is that you get the latest stuff and the disadvantage is that you get a system that is constantly changing, and you must adapt to that. Therefore, it is not suitable for purposes that require consistency such as for server purposes for which you might prefer Ubuntu.

Ease of Use: Although both OS are very user-friendly, there are some things that you will find easier to do on Ubuntu than Fedora such as downloading proprietary software.

An Overview of Debian and Ubuntu

Debian and Ubuntu are both Linux Distributions i.e. Linux based operating systems. Debian is one of the oldest Linux distributions and ‘The Debian Project’ are its developers. As for Ubuntu, it is based on Debian like many modern OS and Canonical Ltd. developed this OS. Both software are free and opensource. Now that you know a bit about them, let’s jump to what you came here for that is the comparison of the two distros (short for Linux Distributions).

Comparison

Stability: Debian is considered more stable than Ubuntu. This is because it has less frequent releases that are thoroughly tested for any errors and bugs before they are made available. As for Ubuntu, it has more frequent releases. Moreover, it is based on the testing branch of Debian rather than stable branch, therefore, it is more susceptible to errors.

Ease of use: When it comes to new users that don’t know much about Linux Ubuntu is better to start off with. It is more user-friendly, and its GUI has a Windows-feel to it. While Debian is more suitable for experienced Linux users. It requires a lot of configuration that newbies wouldn’t understand. Whereas for experts it provides them with an opportunity to tailor the system to their liking.

Releases: Ubuntu has more frequent releases than Debian and its LTS (long term support) releases have support for up to five years. In addition to this, its releases are also regular. This ensures that you get the latest technology timely. On the other hand, Debian releases are less frequent and unscheduled. Its LTS releases have support for three years only. This means that you might not always get the newest stuff on Debian and you do not know when you should expect the updates.

Hardware Requirements: Debian works better on lower-end hardware than Ubuntu. The reason is that Ubuntu adds more features and patches to Debian which makes it heavier. Therefore, Debian is lighter weight and faster than it.

What is Ubuntu and What are Official Ubuntu Flavors?

Ubuntu is a Linux distribution that is open-source and free to download. It is one of the most popular Linux distributions. Official Ubuntu Flavors or Flavors of Ubuntu is just another way of saying different versions of Ubuntu that are released by Canonical Ltd. which is the developer of Ubuntu. Each flavor is developed for different use. Here is a brief overview of each official Ubuntu flavor.

Kubuntu

Kubuntu is popular for its KDE plasma workspace and modern look. It doesn’t require high-end hardware but would not work on very low hardware either. It also lets you customize your desktop.

Lubuntu

It is a lightweight and fast distribution. This OS strives to be user-friendly and energy conserving. It can run smoothly on low-end hardware. It has a Windows-like interface however it isn’t modern looking.

Ubuntu Budgie

As its name implies the distribution uses Budgie desktop environment. It aims to be a simple, user-friendly and elegant OS. It incorporates panel based menu-driven system which is also customizable.

Ubuntu Kylin

This Ubuntu flavor is customized and personalized for the needs of Chinese users. It includes Chinese language and other features to accommodate them.

Ubuntu MATE

This OS also aims for simplicity. It is a replacement of and also the upgraded version of Ubuntu’s previous default desktop that is GNOME 2 desktop. It gives you a lightweight and fast environment with low hardware requirements. Moreover, it provides you with a new interface that gives traditional vibes.

Xubuntu

It incorporates Xfce, which is a desktop environment that is lightweight and stable. Moreover, it is also customizable. The OS can work on low hardware while keeping an elegant and user-friendly interface.

Ubuntu Studio

It also comes with the Xfce desktop environment however, it is aimed at multimedia content creators. The OS includes audio and video tools straight out of the box. It fulfills all the needs for graphic designing, video creation and audio editing that are needed by professionals.  

We have gone through certain Linux Shell Commands in our Part I article. Let’s see a few more basic Linux commands here.

The rm command:

This command is used to remove a file or directory. The -rf option is to remove a file or directory recursively. You must use this command carefully i.e if you run this command in the home directory, or any other important directory, it will delete everything there without confirmation. -f stands for force, it will perform the delete action forcefully. So, please be careful while using this command.

root@monitor:/home# ls
ansible ec2-automate-backup.sh ssbackup.py test
dir1 ssbackup.log ssbackup.py-bak ubuntu
root@monitor:/home# rm -rf test
root@monitor:/home# ls
ansible ec2-automate-backup.sh ssbackup.py ubuntu
dir1 ssbackup.log ssbackup.py-bak
The cp command:

The cp command used to copy a file in the Linux shell. To copy a file/directory recursively use the cp command with the -r flag. For example, we are coping test1.txt to test2.txt

root@monitor:/home# cp test1.txt test2.txt
root@monitor:/home# ls -l
-rw-r--r-- 1 root root 0 Jan 23 16:46 test1.txt
-rw-r--r-- 1 root root 0 Jan 23 16:46 test2.txt

In the below example we are copying test dir to /tmp folder :

root@monitor:/home# cp test /tmp/
The mv command:

The mv command is used to rename or move a file or a directory. In following example we are renaming test1.txt to test.txt.

root@monitor:/home# mv test1.txt test.txt
root@monitor:/home# ls -l
-rw-r--r-- 1 root root 0 Jan 23 16:46 test2.txt
-rw-r--r-- 1 root root 0 Jan 23 16:46 test.txt

In the below example we will move file test.txt to /tmp directory.

root@monitor:/home# mv test.txt /tmp/
root@monitor:/home# cd /tmp/
root@monitor:/tmp# ll | grep test.txt
-rw-r--r-- 1 root root 0 Jan 23 16:46 test.txt
The wc command:

wc is a useful command to count newline, word and bytes of a file

root@monitor:/home# cat test.txt
HI that is a file.
This is the second line.
And we also have a third line.
root@monitor:/home# wc -l test.txt
3 test.txt
root@monitor:/home# wc -w test.txt
17 test.txt

The -l flag is to find the number of lines in a file, -w is to count the number of words in the file.

The echo command:

The echo command echoes a given string to the display.

 $ echo "Hello"
Hello
Redirecting the command output

we can redirect the command output to a file, or as input to another command. | is the most common way to do so. Using this we can count the number of directories in the root (/) directory very easily.

$ ls / bin boot dev etc home lib lib64 lost+found media mnt opt proc root run ˓→sbin srv sys tmp usr var 
$ ls / | wc -w
20
Using > to redirect output to a file!

You can use > to redirect the output of one command to a file, if the file exists this will remove the old content and only keep the input. We can use >> to append to a file, means it will keep all the old content, and it will add the new input to the end of the file.

$ ls / > details.txt 
$ cat details.txt
bin boot dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var $ ls /usr/ > details.txt $ cat details.txt bin games include lib lib64 libexec local sbin share src tmp
$ ls -l /tmp/ >> details.txt
$ cat details.txt
bin games include lib lib64 libexec local sbin share src tmp
total 776
-rwxrwxr-x. 1 fedora fedora 34 Jun 24 07:56 helol.py
-rw-------. 1 fedora fedora 784756 Jun 23 10:49 tmp3lDEho
The man pages.

The man command shows the system’s manual pages. You can use this command to view the help document (manual page) for any command.

Syntax:

man section command. 

Example : man 7 signal.

Linux shell or the terminal is the lifeline of developers to manage their computer systems and data. Things which can be done on the GUI can be done much efficiently on the terminal by using commands. One can not remember all the commands, but with regular usage, one will be familiar with them. The following guide will introduce you to some basic Linux Shell Commands required to use your Linux system efficiently.

Gnome Terminal

Below, you can see a screenshot of the Gnome terminal application. As you can see the command prompt contains the following information:

 [username@hostname directoryname]  

In our case the username is root, hostname is monitor and directory is /root(~).

Gnome- Linux Shell Commands
Gnome Terminal

A terminal and a shell:

Read the articles on Wikipedia to learn about computer terminals and the shell.

Date command:

The date command shows the current date and time.

$ date 
Tue Jan 22 10:13:44 IST 2019

If you want to see the current date and time in UTC you can run the command as follows:

 $ date -u 
Cal command:

The cal command will display calendar in your shell, by default it displays current month.

 $ cal 
January 2019
Su Mo Tu We Th Fr Sa
1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30 31

$cal Feb 2019
February 2019
Su Mo Tu We Th Fr Sa
1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28
The whoami command:

This command will let you know the user account to which you are logged in on the shell.

$whoami
root
The id command:

This command returns user id, group id and groups of the current user.

$ id 
uid=0(root) gid=0(root) groups=0(root)
The pwd command:

The pwd command displays absolute path of current directory.

root@monitor:~# pwd
/root
The cd command:

This command will help you change directory on the shell. In the following example we will move to /etc/ directory.

root@monitor:~# pwd
/root
root@monitor:~# cd /etc/
root@monitor:/etc# pwd
/etc
The . directory and .. directory:

. and .. has special meaning in the Linux. i.e . means current directory and .. means parent directory.

root@monitor:/etc# cd .. 

This command will move us to the parent directory.

The ls command:

The ls command will display the files and directories inside the given directory. If you use the ls command without any argument, then it will return the output for the current directory. Here is the example:

root@monitor:/# ls
bin etc key.txt lost+found opt run srv usr
boot home lib media proc sbin sys var
dev initrd.img lib64 mnt root scripts tmp vmlinuz
root@monitor:/# ls home
ansible ssbackup.log ssbackup.py-bak
ec2-automate-backup.sh ssbackup.py ubuntu

In last command, we provided a path as the argument to the ls command.

The mkdir command:

Using the mkdir command you can create new directory. For example , we are creating test directory in home directory.

root@monitor:/home# mkdir test
root@monitor:/home# ls
ansible ssbackup.log ssbackup.py-bak ubuntu
ec2-automate-backup.sh ssbackup.py test

We can also create directories in a recursive way using -p option:

root@monitor:/home# mkdir -p  dir1/dir2/dir3
root@monitor:/home# ls
ansible ec2-automate-backup.sh ssbackup.py test
dir1 ssbackup.log ssbackup.py-bak ubuntu
root@monitor:/home# ls dir1
dir2
root@monitor:/home# ls dir1 dir1/dir2/
dir1:
dir2
 dir1/dir2/:
dir3

We will learn further basic commands in Part II.

To read about Linux file access permissions please refer our other article here. It will help you understand the Linux files/directories permissions structure.

If you have ownership of a file or directory then you can change access permission of that file for other users. The image given below is showing the permission structure used in Linu.

To change ownership of a file or directory in Linux you have to use chmod command followed by the following attributes.

  • The user for whom you want to change the permission.
  • The type of access permission to add, remove or assign.
  • The list of files and directories for whom you want to change the permissions separated by spaces.

You can change access permission for the users who are in the following categories:

  • the owner of the file (user, u)
  • the group that own the file (group, g)
  • the other users (others, o)

Access permissions refers to read(r),write(w) and execute(x).

As the root user, you can also change the ownership of a file or directory using the chown command.

For example

-rw-r----- 1 jaon users      0 2006-06-23 16:08 checklist.txt
-rw-r--r-- 1 jaon users 53279 2006-06-21 13:16 gnome_quick.xml
-rw-rw---- 1 jaon users 0 2006-06-23 16:08 index.htm
-rw-r--r-- 1 jaon users 70733 2006-06-21 09:35 kde-start.xml
drwxr-xr-x 2 tux users 48 2006-06-23 16:09 local

In the above example, user jaon is the owner of file kde-start.xml and has read, write access to the file but can’t execute it. The users group can read the file and can read this file but can’t write and execute it and the same permissions applied for other users in the next block.

How to modify access permissions for your files?
  • If you want to allow the users group write access to kde-start.xml then use following command:
      chmod g+w kde-start.xml
  • To allow the users group and other users write access to kde-start.xml use following command:
     chmod go+w kde-start.xml
  • To remove write access for all users use this command as follows:
     chmod -w kde-start.xml
  • If you don’t want to allow usersgroup and others to change into the local directory, use following command.
     chmod go-x local
  • To allow write access to other users to two files at same time, use following command:
      chmod o+w  kde_quick.xml gnome_quick.xml

Let’s see the commands used to change ownership of files and directories.

The Root user can change ownership for other user’s data. Login to the server using the root user and its password and run the below command to change the ownership.

chown kristy kde_quick.xml

In above example, we have changed ownership for file kde_quick.xml from user jaon to kristy.

To check if the ownership changed or not, lets list the file using ls -l

ls -l kde_quick.xml
-rw-r--r-- 1 kristy users 47896 2006-06-21 09:46 kde_quick.xml

It is done!

The file system is a logical collection of files on a disk. In Linux, all users including the root user which is also known as the superuser have their own home directories to save their data in.

Linux Directory Structure:

In Linux, you can choose any method to manage files and folders with a file manager or with the command line. The thing you should consider is that you must have good knowledge of the Linux commands to use command line method.

Linux and Unix use a tree-like file system structure with root (/) at the base of the file system. All the other directories spread from there. Each of these directories has a specific purpose. Generally, they hold the same types of information so that you can easily locate files. The following are the common directories found in Linux and Unix:

/

This is the root directory which contains the directories needed at the top level of the file structure.

/bin

This directory contains the executable files. These files are available to all users.

/dev

It holds device files that represent hardware components.

/lib

It contains shared library files and sometimes other kernel-related files.

/tmp

This directory holds temporary files used between system boots.

/boot

It contains files for booting the system.

/etc

This directory host-specific system configuration files.

/home

It contains the home directory for users and other accounts on the server.

/var

Basically, it contains variable-length files such as log and print files and any other type of file that may contain a variable data.

/mnt

This directory used to mount other temporary file systems, such as CD-ROM and floppy for the respective drive.

/proc

This directory contains all processes marked as a file by process number or other information that is dynamic in the system.

/usr

This directory used for miscellaneous purposes and can be used by many users. Additionally, it has administrative commands, shared files, library files, and others

/sbin

It contains binary files, basically for system administration. For example, fdisk and ifconfig utlities.

/kernel

This directory contains kernel files.

Please refer our other file system related articles at following theselinks:

https://linux-documentation.com/linux-file-access-permissions/(opens in a new tab)

https://linux-documentation.com/modifying-file-permissions-in-linux/(opens in a new tab)

I hope these articles will help you understand the Linux File System easily.

We have discussed the most well known Linux distributions such as Ubuntu, Linux Mint, Debian, Fedora in Part I. In this article, we are going to discuss a few more Linux distributions, mainly for Server use.

CentOS

CentOS is another Red hat based community distribution. It is
more standard than Fedora and designed for Server management. It uses the same installer as Fedora and hence it is easy to install. There is a decent selection of applications.

Download Link: https://www.centos.org/download/

openSUSE

openSUSE is a good alternative for Ubuntu and other Linux based distributions. It provides a stable environment for home users along with multiple applications and a decent level of support.

Its installation can be bit tricky for new or inexperienced computer users but once set up you’ll have access to a decent documentation.

Download Link: https://software.opensuse.org/distributions/leap

Arch

Arch distribution provides up-to-date software and drivers but requires more maintenance than other distributions. It requires decent knowledge and willingness to read manuals.

Download Link: https://www.archlinux.org/download/

Lubuntu

Lubuntu is a lightweight version of Ubuntu which is deploying the LXDE desktop environment. It also contains a full set of desktop applications which aren’t as fully featured as the main Ubuntu operating system applications.

Lubuntu provides access to the main Ubuntu repositories which allows you to install any application that you want to use.

Download Link: https://lubuntu.net/tags/download/

Elementary

Elementary has a clean and elegant user interface. It is designed to be lightweight as well as easy to install and use. It is based on Ubuntu and thus provides access to a large repository of applications.

Download Link: https://elementary.io/

Choose the distribution as per your requirements. Once you are familiar with the installed distribution, you will notice that there is no big difference between the common distributions. They share the same kernels and have the same software packages. Furthermore, you can easily install or add any software packages not included in your original installation.

We have already seen some of the famous Linux distributions in our other article. You can check it out here. In this article, we are going to describe the main criteria to choose the perfect Linux distribution.

Linux is based on Unix. Various software developers worked on it and turned it into different ‘distributions’ or ‘distros’. Most of the Linux distros use the Linux kernel (the soul of the operating system). The different desktop environments for these distros are then built around that kernel.

Ubuntu

Ubuntu is a Modern operating system with full hardware integration and a complete set of applications.
If you are worried about the Linux command line, try Ubuntu, because you won’t need the terminal window at all. It is easy to install as well as easy to use with great support.

Download Link: http://www.ubuntu.com/download/desktop

Debian

Debian is one of the oldest and most stable Linux distributions. It is the base for many of the other distributions such as Ubuntu and Linux Mint. It’s community distribution ships with free software and drivers. The Debian repositories offer thousands of applications. There are different versions available for many hardware devices.

Its installation is the easiest because there are various steps you need to go through post-installation to get all of your hardware working.

Download Link: https://www.debian.org/distrib/

Fedora

Fedora is a Red Hat based community distribution. It always comes with up-to-date software and drivers and was one of the first distributions to introduce both Wayland and SystemD. Fedora has a quite regural development update.

Easy to install and contains a good range of software. Not all of the packages are stable.

Download Link: https://getfedora.org/en/workstation/download/

Linux Mint

Linux Mint is a strong option for those who are new to Linux. It is the best starter OS for those who want to switch from Windows/Mac. It provides an impressive amount of customization options with good media support. It is based on Ubuntu, Debian Linux distros.

It is easy to install, contains all the applications you need for general home computing.

Download Link: https://www.linuxmint.com/download.php