Linux commands

sudo!! : Forgot to run a command with sudo? You need not re-write the whole command, just type "sudo!!" and the last command will run with sudo.

2. Python -m SimpleHTTPServer : Creates a simple web page for the current working directory over port 8000.

3. mtr : A command which is a combination of 'ping' and 'traceroute' command.

4. Ctrl+x+e : This key combination fires up, an editor in the terminal, instantaneously.

5. nl : Outputs the content of text file with lines Numbered.

6. shuf : Randomly selects line/file/folder from a file/folder.

7. ss : Outputs Socket Statistics.

8. Last: Want to know history of last logged in users? This command comes to rescue here.

9. curl ifconfig.me : Shows machine's external IP Address.

10. tree : Prints files and folders in tree like fashion, recursively.

11. Pstree : Prints running processes with child processes, recursively.

13. stat : Shows the status information of a file as well as of a file system.

15. Pv : outputs simulating text, similar to hollywood movies.

16. Mount | column -t : Lists mounted file system, in nice formatting with specification.

17. Ctrl + l: clear shell prompt, instantaneously.

18. curl -u gmail_id --silent "https://mail.google.com/mail/feed/atom" | perl -ne 'print "\t" if //; print "$2\n" if /(.*)/;'. This simple scripts, opens up, unread mail of an user, in the terminal itself.

19. screen : Detach and Reattach, long running process from a session.

20. file : Outputs information, regarding types of file.

21. id : Print User and Group Id.
22. ^foo^bar : Run last command with modification, without the need of rewriting the whole command again.

24. at : Run a particular command, time based.

25. du -h --max-depth=1 Command : Outputs the size of all the files and folders within current folder, in human readable format.

26. expr : Solve simple mathematical calculations from the terminal.

27. look: Check for an English word, from the dictionary, in case of confusion, right from the shell.

28. yes : continues to print a sting, till interrupt instruction is given.

29. factor: Gives all the possible factors of a decimal number.

30. ping -i 60 -a IP_address : Pings the provided IP_address, and gives audible sound when host comes alive.

31. tac : Prints content of a file, in reverse order.

32. strace : A debugging tool.

33. disown -a && exit Command : Run a command in background, even after terminal session is closed.

34. getconf LONG_BIT Command : Output Machine Architecture, very clearly.

35. while sleep 1;do tput sc;tput cup 0 $(($(tput cols)-29));date;tput rc;done & : The script outputs date and time on the top right corner of shell/ terminal.

36. convert : converts the output of a command in picture, automatically.

37. watch -t -n1 "date +%T|figlet" : Show animated digital clock at the prompt.

38. host and dig : DNS lookup utility.

39. dstat : Generates statistics regarding system resource.

40. bind -p : Shows all the shortcuts available in Bash.

41. Touch /forcefsck : Force file-system check on next boot.

42. lsb_release : Prints distribution specification information.

43. nc -ZV localhost port_number : Check if a specific port is open or not.

44. curl ipinfo.io : Outputs Geographical Information, regarding an ip_address.

45. find .-user xyz : Lists all file owned by user 'xyz'

46. apt-get build-dep package_name: Build all the dependency, automatically while installing any specific package.

47. lsof -iTCP:80 -sTCP:LISTEN. The script, outputs all the service/process using port 80.

48. find -size +100M : This command combination, Lists all the files/folders the size of which is 100M or more.

49. pdftk : A nice way to concatenate a lot of pdf files, into one.

50. ps -LF -u user_name : Outputs Processes and Threads of a user.

51. Startx — :1 (This command creates another new X session).

top 6 files that eat up your space:

du -hsx * | sort -rh | head -6

• Alt+Backspace: Deletes the previous word.
• Alt+F: Skips ahead to the next space.
• Alt+B: Skips back to the previous space.
• Ctrl+U: Cuts all text up to the cursor.
• Ctrl+K: Cuts all text after the cursor until end of line.
• Ctrl+A: Moves the cursor to the start of line.
• Ctrl+E: Moves the cursor to the end of line.