SAIT WBDV

Web Developer Fast Track - Winter 2021

Command Line Cheatsheet

Terms

Command Line Interface (CLI)
An alternative to Graphical User Interfaces (GUI) that are based on mouse clicks. Terminal apps come in a few flavours; in this course you can use a unix terminal of your choice.</dd>
The Terminal
A nickname for an application that understands one or more Command Line Interfaces (CLIs).
Workspace
A dedicated folder(s) on your system for the projects you’ll be working on.
Command Prompt
Usually the last line shown in the terminal where you enter your commands. Often represented by a $ or # in examples online (see warning below).

Notice: General information will be displayed in boxes such as this one. Warnings will be in red (see below) for information that will help you avoid potential problems.

Warning: There are two flavours of “command line”: Windows and Unix. We will be using the latter: Git Bash (installed along with Git) on Windows and Terminal on Mac (Mac is unix-based so almost any terminal app will do; Tony uses iTerm).

Most of the command line tools we will be using in this course (like Git, Node and NPM) will depend greatly on which directory you are in. We will cover the three system commands that help up us navigate the file system.

Note: The examples below start with a $. Do not include this when typing commands; it’s there to represent the command prompt.

  • pwd
    • displays your ‘present working directory’. This will usually default to your home folder when you first open your terminal.
  • ls: Lists the contents of your current directory. The -l flag lists extra information and -a lists hidden files. -la will list extra information and also all hidden files. Examples:
    • $ ls (lists file and directory name of the current folder)
    • $ ls -l (lists full directory information)
    • $ ls -a (lists hidden files)
    • $ ls -la (lists full information plus hidden files)
    • $ ls -lh (lists full information plus formatted file sizes)
  • cd: changes your directory based on the path you provide after the command (separated by a space). Examples:
    • $ cd Documents/sait
    • $ cd / (moves to the top root folder)
    • $ cd (moves to user home folder)
    • $ cd - (moves to the last directory)
    • $ cd .. (moves up one directory level)
    • $ cd ../../some-directory (moves up two directories and into “some-directory”)
  • find: find a file within the filesystem. Specify the parent directory to search from
    • $ find / -name filename (will search for the filename in every directory under root. NOTE: you can specify other parent directories to search within)
  • less: show contents of a file in the terminal. Useful for quickly checking through a file without having to open it in your text editor
    • $ less filename (write out full filename. If the file is in a different directory from your current working directory, remember to include the path)

Notice: Below are Pro-tips that will give you some hints on how the pros do things. In this case, there are some quality of life tips that will reduce the grind if using the command line.

CLI Quality of Life Tip #1: The tab key auto-completes file names and directories.

CLI Quality of Life Tip #2: Use the Up Arrow to browse through the history of last used commands.

Questions to Consider

  • What is the starting directory when you open a terminal on your system?
  • What files and directories are in this initial directory?
  • What file did you last open? Try to find it using only the terminal.
  • What’s at the top of your directory structure? How do you get there?
  • Using the terminal, find the directory you’ve chosen to store your projects.