Introduction Linux

21. sort: Sorts the lines of a file.
22. export: Sets environment variables.
23. zip: Compresses files into a zip archive.
24. unzip: Extracts files from a zip archive.
25. ssh: Connects to a remote server using the Secure Shell protocol.
26. service: Controls system services (start, stop, restart).
27. ps: Displays active processes.
28. kill and killall: Terminates active processes by process ID or name.
29. df: Displays information about disk space usage.
30. mount: Mounts file systems.
31. chmod: Changes file permissions.
32. chown: Changes file ownership.
33. ifconfig: Displays network interface configuration.
34. traceroute: Traces the network route to a destination.
35. wget: Downloads files from the internet.
36. ufw: Configures the Uncomplicated Firewall.
37. iptables: Manages the Linux firewall rules.
38. apt, pacman, yum, rpm: Package managers for managing software packages.
39. sudo: Executes a command with elevated privileges.
40. cal: Displays a calendar.
41. alias: Creates custom shortcuts for commands.
42. dd: Copies and converts files.
43. whereis: Locates the binary, source, and manual pages for a command.
44. whatis: Displays a brief description of a command.
45. top: Displays live system resource usage and active processes.
46. useradd and usermod: Adds or modifies user accounts.
47. passwd: Sets or changes user passwords.