Command Booster Pack

There are a lot of useful commands in the real world. Today you’ll get a chance to play around with some of the most commonly used commands. The goal here is not to walk away knowing everything. The goal is to get a glimpse of a lot of different commands so that you know what’s out there and so you can look them up in more detail when you need them.

Before you start

• man <command>

• <command> --help

• You probably want to make a directory to play around in. You’ll probably make some files, and it’ll be easier to avoid overwriting stuff and clean up if you make a directory just for today.

  mkdir sandbox
  cd sandbox
  

  At the end of the day:

  rm -r sandbox
  

• To stop a command that’s going on too long, use <Ctrl-C>

Commands to try on your own

Try each of these out. See what they do, and write a short description down.

Disclaimer: It’s possible not all of these commands will be installed everywhere you try to run them.

• pwd
• find (This will be more exciting if you try find ~ )
• du (This will be more exciting if you try du -h ~ )
• df
• uname
• top
• users
• ping <website>

Try passing a file as an argument to each of these. Your ~/.bashrc is probably a good file to try.

• head <file>
• tail <file>
• less <file>
• cat <file>
• tac <file>
• rev <file>
• sort <file>
• wc <file>

Some more commands:

file ~/.bashrc


wget http://i.imgur.com/djox7m5.png
file djox7m5.png


curl www.cmu.edu


cd ~
zip dotfiles.zip .bashrc .bashrc_gpi
mv dotfiles.zip sandbox
cd sandbox
unzip dotfiles.zip
ls -a


touch newfile
ls


ln -s ~ myhomefolder    ("ln" is short for "link".)
ls myhomefolder/


alias newcommand='head ~/.bashrc'
newcommand
unalias newcommand
newcommand    (This should fail.)

Maybe you can try these?

You probably can’t or don’t want to, though. These are commands to use if you won the server or computer you’re running them on. This is distinctly not the case for the Andrew Unix machines.

• adduser
• passwd Changes your password.
• su <username> Start running as if you were a different user.

• su Start running as root (administrator).

  Careful, though. With great power comes great responsibility.

• sudo <command> <arguments> Just do one command as root.

Starting applications

You can start most applications by running their name as a command. Examples:

• google-earth
• libreoffice ~/Documents/homework/essay.docx

On Macs, the open command will open a file with the default program.

• open djox7m5.png