Useful Console Commands

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Developers typically like working on the command line (shell). The shell is a REPL for running commands against the operating system directly. By running commands in this manner, developers can more efficiently use their machines to get work done. Common tasks that developers use the terminal for are:

Navigate to a directory
Creating a directory
Creating a file
Opening a file
Running a program

There are many more commands and tools that the shell can use. What makes these powerful and valuable is that eventually, we will be able to chain these commands together and run scripts that help automate the boring, repetitive tasks.

Interacting with our operating system comes in two parts. The first is the shell, the actual REPL we will interact with, the second being the terminal program we use to run that shell. You can think of the terminal like your browser and the shell like the web page it contains.

Different operating systems use different tools for both the terminal and the shell. For instance, on Mac OS we use the Terminal application to interact with our shell of either bash or zsh (depending on your OS version). On Linux, we use a terminal application that varies based on which version of Linux you are using. However, the shell is typically either bash or zsh. On Windows, both the terminal and shell are called PowerShell.

The commands might be slightly different across all operating systems, but the ideas are the same.

Useful commands

The following commands are the basic commands you will need to be familiar with as a new developer. These commands are not an exhaustive list but rather a resource to help guide you when you are lost.

Show my current directory

pwd

What does it do?

This simple command stands for "print working directory." This command shows you which directory you currently are in by printing its name. Knowing the current directory helps you to understand what commands you can run and what tools, programs, and files you can manipulate.

When to use pwd?

Use pwd to help you see where you currently are in your terminal.

Create a new directory

mkdir folder_name

What does it do?

This command allows us to create a new directory (folder) from the terminal. The directory is created within whatever directory is currently active. (use pwd to check if you need to)

When to use mkdir?

Use this command to create a new directory. We can, and should, make new folders to help us manage our projects.

List files and directories

ls

What does it do?

This command lists the files and directories in your current directory.

When to use ls?

Use ls to help you see what files are in your current directory.

Change Directory

cd directory name

What does it do?

To navigate our computer, we need to be able to change directories and navigate our file structure. The file structure on our system is similar to a tree. When using your desktop user interface (Finder, Windows Explorer, etc.) and we open a new folder, we say: we are going down into the new folder. To go down into a new directory from the shell, we use the command cd.

The cd command changes our current working directory to the new directory. Switching directories is roughly equal to double-clicking a folder in your desktop user interface.

To go back up to the parent directory, we use a special directory name called .. which means "the directory that is my parent."

For example, consider the following folder structure.

Home
- football-rosters
- budget
- family-pictures
  - clearwater-beach-2019
  - disney-world-2018

Home is the parent directory of football rosters, budget and family-pictures; and family-pictures is the parent of clearwater-beach-2019 and disney-world-2018.

Starting out, we will be in our Home directory.

Home <=- You are here
- football-rosters
- budget
- family-pictures
  - clearwater-beach-2019
  - disney-world-2018

If your current directory is home, you can run:


cd family-pictures

Home
- football-rosters
- budget
- family-pictures <=- You are here
  - clearwater-beach-2019
  - disney-world-2018

The above command changes my current directory to be family-pictures. If you want to navigate down further into disney-world-2018 you can use cd again:


cd disney-world-2018

Home
- football-rosters
- budget
- family-pictures
  - clearwater-beach-2019
  - disney-world-2018 <=- You are here

If you want to move back up one directory, you run:


cd ..

And you will again be in the family-pictures directory again.

When to use cd?

Use cd to navigate to a new folder, a current project, or another place on your computer.

Open VS Code

code folder_name

What does it do?

This command is how we open our IDE, Visual Studio Code (VS code). An IDE is a text editor (like a word processor) with tools and features tailored to developers. We use VS Code to write and edit our code.

Often we want to open VS Code with the contents of our current directory. Just like .. is a special directory meaning the parent directory there is another special directory named . that means the current directory

So to open the current directory's content in VS Code you use:


code .

When to use code?

Use this when you want to open a file or project and write or edit code or files.

node

node file_name.js

What does it do?

Node is a runtime for javascript. Using node, we can run javascript on our machines without having to be in a browser.

When to use node?

We typically use this for running JavaScript code interactively (as a REPL) or to run a JavaScript code file. We use this in one of two ways.

First, we use this as a REPL to run lines of JavaScript. This way allows us to run an individual or a small number of lines of code to test out an algorithm or idea.

The second time to use this to the run *.js files. This is how we run node files or any javascript files that do not interact with the DOM.

Usually, students at the beginning of their journey do not run node directly but use node to run other tools.

npm

npm [command][parameters]

What does it do?

npm stands for "node package manager". This program is a way for us to install tools and packages.

When to use npm?

You use npm to install new tools in the command line from time to time.

Generally, you need to run this command when dealing with project setups or to use new tools.

git

git [action]

What does it do?

Git is a version control system for tracking changes in source code during software development. Git is designed for coordinating work among programmers and is one of the most common version control systems you will see as a developer.

Git is different than GitHub. GitHub is a web-based provider of a git, whereas git is the underlying tool. Github runs git, and we save our changes to our code to GitHub using git.

When to use git?

You want to use git to save your changes. The most common tasks with git are usually "making a commit" or "pushing to GitHub". Git can do much more. The commands we'll show here are mostly what a new developer needs to know.

To create a commit on our local machine, you run:


git add  .
git commit -m "A message about what you did."

To send your changes to GitHub, you run:


git push

To learn more about git check this out

hub

hub [command]

What does it do?

Hub is the last bit of glue that ties our local git code and repositories to GitHub. Hub is a command-line program that lets you more easily work with GitHub, the place where we store our code.

When to use hub?

This tool is primarily used in the background to set up and help manage your repositories.

The most useful command is to open the GitHub page corresponding to your project:


hub browse

You can also create a new GitHub repository by using:


hub create

Within this command, hub will use the name of the directory you are in as the name of the project. If you would like to use a custom name, you may use the following, substituting CUSTOM-NAME with your project name. NOTE, it should not use spaces in the name.


hub create CUSTOM-NAME

Open the current directory in your desktop user interface

Mac OX

open folder_name

Windows

start folder_name

What does it do?

This command opens your present working directory in your file explorer for you. Even though the shell is robust, sometimes the file explorer is easier to use.

When to use start/open?

We use this when we need to see the current directory in our file explorer.

Stopping long-running tasks

Pressing both control and c - commonly denoted as ctrl + c.

What does it do?

Sometimes when we are running tasks in our shell, we want to stop the task as it is running. Using this shortcut, we stop tasks that are already running.

When to use ctrl+c?

You need to stop the program you are running and return to being able to type commands in your shell.

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