Shell Scripting

Shell scripting in Linux allows users to automate tasks using shell commands and scripting constructs. Here are some basic commands and concepts:

• Shebang: #!/bin/bash at the beginning of a script specifies the shell interpreter.
• Variables: VAR=value assigns a value to a variable.
• Conditional Statements: if, else, elif for decision-making.
• Loops: for, while for iterating over lists or executing commands repeatedly.
• Functions: function_name() { ... } for defining reusable code blocks.

Package Management

Package management involves installing, updating, and removing software packages. Basic commands include:

• Installing Packages: apt-get install <package> (Debian-based), yum install <package> (Red Hat-based).
• Updating Packages: apt-get update, yum update.
• Removing Packages: apt-get remove <package>, yum remove <package>.

Virtualization

Virtualization allows running multiple operating systems or environments on a single physical machine. Basic concepts include:

• Hypervisor: Software that enables virtualization (e.g., VirtualBox, KVM).
• Virtual Machine (VM): Guest OS running on a host machine.
• Commands: virsh for managing KVM-based VMs, VBoxManage for VirtualBox.

File Storage

Managing file storage involves handling disks, partitions, and file systems. Basic commands include:

• Disk Partitioning: fdisk, parted for creating and managing partitions.
• File Systems: mkfs for creating file systems (e.g., mkfs.ext4 for Ext4).
• Mounting: mount to attach a file system to the directory tree.
• Unmounting: umount to detach a file system.

User and Group Management

Linux allows creating, modifying, and deleting users and groups. Basic commands include:

• User Management: useradd, usermod, userdel.
• Group Management: groupadd, groupmod, groupdel.
• Permissions: chmod for changing file permissions, chown for changing file ownership.

Process Management

Monitoring and controlling processes is essential for system administration. Basic commands include:

• Listing Processes: ps to list processes, top for real-time process monitoring.
• Killing Processes: kill to terminate a process by ID or name.
• Monitoring: htop for interactive process viewer.