1. System Information and Configuration

• uname -a: Displays system information (kernel, architecture, etc.).
• hostname: Shows the system’s hostname.
• uptime: Displays system uptime and load averages.
• cat /etc/os-release: Displays OS version and details.
• dmesg: Prints kernel messages (useful for troubleshooting hardware or kernel-related issues).
• whoami: Displays the currently logged-in user.
• id: Displays user ID (UID), group ID (GID), and group memberships.

2. User and Account Management

• who: Shows currently logged-in users.
• w: Displays who is logged in and their activities.
• last: Displays login history.
• passwd: Changes a user’s password.
• useradd <username>: Creates a new user.
• usermod: Modifies a user account.
• chage -l <username>: Lists user account expiration details.
• groups <username>: Displays groups a user belongs to.

3. Process Management