Category: Debian

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.

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 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

Please refer to our other article regarding an Introduction to Linux Operating Systems.

In this article, we are going to see what are the Linux features which makes it the first choice of developers as well as the best option for Server Management and Web Hosting.

Graphical User Interface:

Basically, Linux is a command line based OS that allows converting to a GUI based OS by installing packages. It also supports Graphical Customization.
GNU/Linux is an OS allowing you to choose the GUI you like, for example from Arch Linux and install it on your system. You can change this GUI pattern any time you want.

Control Over the Entire Base System:

GNU/Linux is great when it comes to fixing errors related to any system package or tool. As the system is built with modular pieces, if any package breaks, you can either uninstall then re-install the problematic package via the Command Line or the graphical interface. Also, you can find a different tool as a replacement.

Packages:

Linux has its own software repository which allows users to download and install many applications. In Debian, there is the apt-get command that installs a program without compiling. The exact command is “apt-get install programname“. You can even use APT to install Chromium (a graphical application) if you wish. Similerly, Red Hat has yum, Arch Linux has pacman, etc.).

Multiuser capability:

More than one user can access the same system resources like memory, hard disk, etc. from different terminals.

Multitasking:

More than one function can be performed concurrently by dividing the CPU time intelligently.

Security:

It provides security in three ways i.e authentication, by giving user id with the username, authorization by giving permission to read, write and execute and encryption by converting files to an unreadable format.

Live CD/USB:

Almost all Linux distros provide live CD/USB so that users can run it without installing it.

Portability:

It supports different types of hardware.

File System: 

Files and directories are arranged in a hierarchical structure which is easy to understand by users.

Programmer-friendly: 

Linux comes with everything you need to compile both C and C++ programs out of the box, regardless of distribution. It supports different languages as well.

Linux is a free and open source operating system released in 1991 for computers. But today, it works on computers, servers, mainframes, mobile devices, and embedded devices. Linux is one of the most popular versions of the UNIX Operating System. It was designed considering UNIX compatibility and thus it’s quite similar to Unix.

Linux-based operating systems are mostly used by developers to get their work done and develop something new. They are choosing a Linux distro for development because it’s easy to use as well as compatible with most of the programming languages i.e Java, PHP, HTML etc. Today, Linux is ideal for commercial network devices and enterprises who want to use it to customize their own network and data center infrastructure.

The following is a list of best Linux distributions for Development and Server Management:
  • Debian
  • Ubuntu
  • Fedora
  • CentOS/REDHAT
  • Raspbian
  • And more

Please check out our other article to get more information about these Linux distributions here.

Primary Components of Linux

These are the three primary components of this operating system:

Kernel

The kernel is a core part of the operating system. It performs all major activities. It consists of various modules and interacts directly with the internal hardware. The Main function of the kernel is to send instructions to the CPU, peripherals, and memory.

System Library

System libraries are the programs that allow application programs or system utilities to access the Kernel’s features. These libraries are responsible for executing most of the OS programs. They don’t have the kernel module’s code access rights.

System Utility

System Utility programs are responsible to perform specialized, individual level tasks. Beyond tthe operating system it has two modes such as Kernel Mode and User Mode. The system runs programs under one of these modes.

Kernel Mode vs User Mode

Kernel Mode has full access to all resources of the system. In kernel mode programs represent a single process. It executes in single address space and does not require any context switch. Because of which this mode is very efficient and fast.

User programs and other system programs run in User Mode. It has no access to system hardware and kernel code. User programs use system libraries to access kernel functions to get the system’s low-level tasks done.