What is a Kernel

Walnut kernel

If you work with computers, or hang around computers long enough, you might come across this term “kernel”. In this article we will see what the kernel is, why is it important and where did it come from. Thing that most people forget is all that computers are doing is following instructions, repeating one instruction … Read more

Linux File System Structure Explained

Most people who have used Linux have seen the root directory but not everybody understands what the directories are used for. When a Windows user opens the file manager, everything looks good when they are in their home folder, however, problems start when they explore up the tree looking for the “C Drive” :). For … Read more

Changing Ownership of Files in Linux

Two Files

Let’s see how to change file ownership on linux system. In our example we have two files owned by cicnavi user (enter ls -l to show files with long listing). To change the ownership of the files we can use the chown command. This command can only be run by the root user.  Chown command can … Read more

Change Permissions For Files and Folders in Linux

As we said in Permissions and Ownership article, all files are owned by a user, a primary group and a world (everybody, others) group. If we list directory content with the command: ls -l we can see examples of the ownership. In our example, we created these files as the cicnavi user and that’s why the files … Read more

File Permissions and Ownership in Linux

File system permissions in Linux are a little bit different than permissions in Microsoft Windows. File system permissions in the UNIX world use the POSIX standard, which basically says that every file and directory is owned by both a user and group. Every user has a primary group membership. When any any file is created by … Read more

Users and Passwords in Linux

Before you start Objectives: Learn how to set or change passwords for users on Linux machines. Prerequisites: no prerequisites. Key terms: passwd, Linux, administration, reset, set, management  Working With Passwords Today, we won’t see passwords in the /etc/passwd file any more. Instead, they are moved to the /etc/shadow password file, where they are encrypted. By default, shadow passwords … Read more

Root User in Linux

Before you start Objectives: Learn what is root account, how should it be used, and how to change to it to execute commands. Prerequisites: no prerequisites. Key terms: root, administrator, Linux, system, su command. su –  root User The root user account on Linux system is created during the installation process and is a superuser which can perform … Read more

Administrative Rights and Users in Linux

Before you start Objectives: Learn how to allow users to run administrative commands using sudo. Prerequisites: you have to know how to manage users and how to manage groups in Linux. Key terms: sudo, root, user, command, Linux, sudoers file.  sudo sudo is a very useful tool used to delegate administrative rights to other users. One of the advantages (or … Read more

Quota Management in Ubuntu

Before you start Objectives: Learn what are quotas, and how to configure quotas on Ubuntu machine. Prerequisites: no prerequisites. Key terms: quota, Ubuntu, configuration  Quotas Quotas limit the amount of space users and groups have available for either the number of files and directories they can create or the total size of all their files and directories. File system … Read more

Group Management in Linux

Before you start Objectives: Learn how to create new groups, manage existing ones, and how to change group membership in Linux. Prerequisites: no prerequisites. Key terms: groupadd, groupmod, groupdel, usermod, Linux  Creating and Managing Groups To add a new group we can use the ‘groupadd’ command. If we only enter the ‘groupadd’, we will see the syntax of … Read more