Introduction

Linux is an open-source operating system that is widely used in servers, supercomputers, and embedded devices. As a Linux administrator, you will be responsible for managing and maintaining these systems to ensure optimal performance and security.

Basic Linux Commands

• ls – list files and directories
• cd – change directory
• mkdir – create a new directory
• rm – remove files and directories
• cp – copy files
• mv – move or rename files

User Management

As a Linux administrator, you will need to create and manage user accounts. You can use the useradd command to create new users and set their password.

sudo useradd -m -s /bin/bash myuser

The -m option creates the user’s home directory and sets the default shell to /bin/bash. You can also set other options such as the user’s group membership and password expiration.

File System Management

Linux has a powerful file system that allows you to manage files and directories using various commands. You can use the mkdir command to create new directories, and the rm command to remove files and directories.

sudo mkdir /my/new/directory

You can also use the cp command to copy files and directories, and the mv command to move or rename files.

Networking and Security

As a Linux administrator, you will need to ensure that your system is secure and protected from unauthorized access. You can use various networking and security tools such as firewall-cmd and fail2ban to configure your firewall and protect against brute force attacks.

sudo firewall-cmd --permanent --add-rule ipv4 input ssh

You can also use the selinux command to enable or disable SELinux, and the chroot command to change your root directory.