The command line is a place where you input commands that your computer will execute. These can be simple commands like creating a folder, but also much more complicated ones. On Linux and Mac, most people use the Terminal application to enter commands, while on Windows I suggest you use PowerShell.

If you forget what a command does or how exactly to use it (which happens to me all the time) you can look it up on tldr.ostera.io, or if you want more detail (more than you need 99% of the time) you can type man <command>, for example man ls if you want to know everything about ls.

We will stick with the following commands. Note that I use <argument> to denote an argument, i.e. a path or a name of a file or command that applies to your case. You shouldn’t actually type < and >.

  • pwd – print working directory.
  • ls – list working directory.
  • cd <path> – change directory.
    • cd Code – switches to folder named “Code”.
    • cd .. – switches to the parent of the current directory.
    • cd – (no arguments) switches to your home folder
  • cp <file> <destination> – copies file.
    • cp poem.txt copied_poem.txt
  • mv <file> <destination> – moves file.
    • mv poem.txt ../poem.txt – move poem.txt to the parent of current folder.
    • mv poem.txt another_name.txt – rename poem.txt to another_name.txt.
  • rm <file> – removes file.
  • mkdir <dirname> – creates directory.
  • rmdir <dirname> – removes directory.
  • man <command> – shows manual page of command.
  • clear – clears terminal window.
  • python <program> – our star: calls the Python interpreter to execute a program.
    • python hello_world.py
    • python – (no arguments) opens interactive Python interpreter.

Two very useful tricks:

  • press the up and down arrows to cycle through commands you’ve entered previously.
  • press Tab to auto-complete a command you’re currently typing.