command_tips.md

good things to know

1. ls: list the contents of a directory
2. cd: "change directory"

• cd . go to the current directory.
• cd .. go up a directory
• cd ~ go home.
• cd without a directory, go home.

3. vi, nano text editors. :q quits vim.
4. man the manual.
5. sudo do as super-user. USE AT OWN RISK.
6. ssh secure shell. Use to connect to servers.
7. rm remove a file.
8. mkdir make a directory.
9. cp copy a file or directory
10. mv move a file or directory
11. git use Git commands.
12. less read a file in the command line.
13. !! replaced by previously run command. !1, !2,... go further back.
14. cat output a file to the command line.
15. echo print a message.
16. cmd1 | cmd2 take the output of cmd1 and put it in cmd2. Called piping.
17. cmd > file take the output of cmd and put it in a file. This replaces everything in the file. cmd >> file appends instead of overwriting.
18. cmd1 && cmd2 and cmd1 || cmd2 Logical operations. Do cmd1 and cmd2, or cmd1 or cmd2.
19. chown take ownership of a file. Useful if you download something as root.
20. chmod make a file executable, among other uses.
21. touch create a file. More precisely, update the modification time of a file, or create it if it doesn't exist.
22. ssh-keygen generate a new ssh key for passwordless login on remote servers.
23. wget download a file from the interwebz.
24. top, htop, ps -eax display process information.

And now for something a little different.

1. lolcat pipe a command into lolcat to make the output colorful. Some commands are broken for this.
2. cowsay similar to lolcat, make a cow say the output.
3. toilet make the output in big ASCII letters. Try mixing these three together to get some interesting results.
4. sl make a train. A punishment to teach ls.
5. ddate get the day in a fictional calendar.
6. fortune get a random quote.
7. neofetch display system information with a cool logo. Looks nicer than cat /proc/cpuinfo.
8. cmatrix make it rain digital rain.