How to Check if the Current Directory is a Git Repository

Use this command in your Terminal to determine if the directory you are currently in is a Git repository or not:

git rev-parse --is-inside-work-tree

The shell prints true if you are in a git repository’s working tree. It prints false if you are inside the ‘.git’ tree but not the working directory, and it prints a fatal error if it’s neither (not connected to any git repo).

Both ‘true’ and ‘false’ are printed on STDOUT with an exit status of 0, the fatal error is printed on STDERR with an exit status of 128.

How to Build a Node.js Project for Beginners

First, make sure you have Node installed. I’m not going to show how to do that in those tutorial. For developers that already know how to use Node, this tutorial can serve as a guide to help jog your memory whenever you forget all the steps to building a new Node.js project.

Once you have Node installed, you can write these commands in Terminal to get started:

mkdir folder-name    (create a new folder)
npm init             (initialize Node Package Manager)
touch index.js       (create server file)

For the npm init step, it will make you click through a bunch of prompts/set-up questions to set up NPM in your folder.

For your server file, it doesn’t matter what it’s name is as long as you make sure it has the same name as the one you defined in the NPM initialization questions.

In Terminal within your project directory, add these NPM packages to your project using the command npm i or npm install

npm i express         (install express - a Node web framework)
npm i -D nodemon      (install nodemon as a dev dependency)

Open up your server file (index.js) in a code editor (I prefer Visual Studio Code) and type this Node code:

const express = require('express');

const app = express();

const PORT = process.env.PORT || 4000;

app.listen(PORT, console.log(`Server started on port ${PORT}`));

The Express framework is the most popular Node backend web framework by far and it will make working with Node for the web 100x easier.

To run this and make sure it works, type this command in your Terminal (make sure your in your project directory):

nodemon index.js

The Terminal should output the string “Server started on port 4000” (or port 5000, 6000, etc. based on what you put in your code).

This means that the project is running on the specified port on your localhost.

Find and kill process locking a port on Mac

This error was caused when I tried to locally run a server on a port that was already being used by another server that I had previously left running and forgot to turn off.

This command will show you all the process(es) running on a port and their PIDs

sudo lsof -i :3000

Kill the process by replacing <PID> with the process’ PID number

kill -9 <PID>

MySQL in the Terminal

The default path to MySQL on Mac is /usr/local/mysql/bin.

If you type mysql --version, you may get an error saying “command not found.” This is because you don’t have the MySQL command in your path.

To solve this, you can do one of two things:

# This will add MySQL to your current session (will be lost when you close Terminal)
export PATH=${PATH}:/usr/local/mysql/bin
# Permanantly
echo 'export PATH="/usr/local/mysql/bin:$PATH"' >> ~/.bash_profile

Copy and paste whichever command you prefer into Terminal. Close & reopen your Terminal window after you run the command.

Now, if you type mysql --verison, it should show you your version of MySQL.

Log in and use MySQL in the Terminal using this command: mysql -u root -p. It will ask for your password; make sure you use your MySQL password, not your system password

Ctrl + L to clear the prompt

Show users:

SELECT User, Host FROM mysql.user;

Create user: When you create a new database for a new application, you will probably want to have a specific user for that database rather than using the root user

CREATE USER 'someuser'@'localhost' IDENTIFIED BY 'somepassword';

Leave the MySQL Terminal

quit