50 Common Linux Console Commands You Should Learn

I have listed below 50 commonly used Linux / Unix commands that we think every geek should learn by heart. These commands are vital for your complete access to Shells and Consoles.  Print them out. Hang them near your monitor. Practice them. Only constant practice will let you retain the usage and utility of all these console commands. Enjoy the list.

1. clear: Clears the terminal window
2. ls directory: List contents of a directory
3. cat filename: Displays the contents of a file in the terminal
4. rm filename: Removes a file
5. cp sourcefile detstinationfilename: Copies a file
6. passwd: Changes password
7. motd: Message of the Day
8. finger username: User information lookup program
9. startx: Starts an X Window System server
10. less filename or more filename: Displays the contents of a file in the terminal one page at a time
11. info: Displays information and documentation on shells, utilities and programs
12. lpr filename: Sends file to printer
13. grep string filename: looks through files for strings
14. head filename: Displays first 10 lines of file
15. tail filename: Displays last 10 lines of file
16. mv existingfilename newfilename: Moves or renames file
17. file filename: Displays information about file contents
18. echo string: Copies string to terminal
19. date: Displays current date and time
20. cal: Displays calendar
21. gzip filename: Compresses a file
22. gunzip filename: Decompresses a compressed file
23. which command: Displays path to command
24. whereis command: Displays paths to locations of commands
25. who: Lists currently logged on users
26. finger username@hostname: Obtains detailed information about a user currently using the system
27. w: Lists currently logged on users with processing usage
28. mesg y/n: Sets options for letting other users write you messages
29. write user: Sends message to other users
30. talk user: Allows two way chat to other users
31. chmod permissions filename: Changes file access permissions
32. mkdir directoryname: Makes a directory
33. rmdir directoryname: Removes an empty directory
34. ln existingfile new-link: Creates link to an existing file (hard link)
35. df: Displays all mounted filesystems
36. top: Displays updating list of currently running processes
37. tty: Displays the name of the terminal in which the command was issued
38. kill PID or %job number: Aborts a process by PID (Process Identification Number) or job number
39. jobs: Displays a list of current jobs
40. netstat: Displays network connections
41. traceroute host: Prints the route packets take to the host
42. nslookup: Queries Internet domain name servers
43. hostname: Displays system identity name
44. rlogin host: Utility to connect to a remote system
45. telnet host: Utility to connect to a remote system (similar to rlogin but more interactive)
46. rcp file remotemachine: Used to copy from a remote computer
47. ftp: Utility to transfer files between systems on a network
48. rsh command: Utility to run a command on a remote system without logging in
49. ping host: Utility used to test connection to a remote system
50. lcd directorypath: Changes local machine directory while logged on to remote machine