A quick introduction to command-line development with Composer
Posted on February 12, 2019
!Warning: This post is over a year old. I don't always update old posts with new information, so some of this information may be out of date.
Tighten is about to publish a blog post about how to convert your WordPress site to Jigsaw, and I wanted to make sure we had a good tutorial somewhere teaching the basics of working on the command line and using Composer.
So, if you've worked with WordPress before, but you've never worked on the command line or you don't have experience working with Composer, this is for you.
Getting comfortable with the command line
First, let's get you set up with a terminal client, or the application that allows you to interact with your computer's command line.
If you're working with desktop Linux, you already know how to open up a terminal session. No new steps here.
If you're working with a Mac, you can find an application named "Terminal" in your Applications folder, under the "Utilities" folder. Open that, and you're ready to go.
If you want a bit of an upgrade, there's a free Terminal replacement named iTerm2 that most developers prefer to Terminal.
I asked on Twitter about the best way to get a functioning terminal on Windows, and the answers varied, but the most common recommendation was GitBASH, followed by CMDer.
I'm going to recommend GitBASH; you need to have installed Git on your Windows machine anyway, and it comes with GitBASH, so that seems a good place to start. Check out the Git for Windows web site to learn how to install Git and get access to GitBASH.
If you want to upgrade your terminal a little, here's a quick video on how to install and use CMD-er after you install GitBASH: https://www.youtube.com/watch?v=Xm790AkFeK4&feature=youtu.be
If you're running Windows 10, you can get system-level support for terminal access with the WSL (Windows Subsystem for Linux). I don't know exactly how easy it is to set up, but a lot of folks recommended it; here's an intro video: https://www.youtube.com/watch?v=Cvrqmq9A3tA
Getting used to the terminal
The first thing you'll want to get used to is how the terminal works. You're going to see a prompt in front of you that looks something like this:
Exactly what you're going to see here will change based on your environment and the theme loaded by your shell, but most terminals will show at least these details:
- Machine Name (Launchpad-McQuack): This is the machine-friendly name of your local machine.
- Path (~): This is where you are in your directory structure. If you see a tilde (
~) in the path, that means your user's home directory. On macOS this is
- Username (mattstauffer): This is your username on your local machine.
- The prompt (
$): There will be a character to the left of your cursor that just means: "You can type here". It's often a
>, but some terminal themes use other characters.
Moving around, and paths
If you want to move to another directory, you'll want to use the
cd command. So, if I want to move to the directory
/Users/mattstauffer, I can type
Because that path starts with a
/, I'm telling my terminal that I'm defining the absolute path I want to go to. That means "this path I'm defining is at the root of the computer's file system". Like this: Root / Users directory / mattstauffer directory.
But if I were to start it without the
/, that would mean "go to this path beneath the directory I'm already in". So if I typed
cd Users/mattstauffer, and I was already in the
/Users directory, I'd be saying "take me to
/Users/Users/mattstauffer", which, of course, wouldn't work.
For me, all of my web projects live in the
/Users/mattstauffer/Sites directory, which I can shorten to
~/Sites. So here's what it looks like when I open up my terminal and want to work on my web site:
cd ~/Sites cd mattstauffer-com # (which is the same as:) cd ~/Sites/mattstauffer-com # (which is the same as:) cd /Users/mattstauffer/Sites/mattstauffer-com
If you want to list all of the files in your current directory, you'll want to use the
ls command. I prefer adding the
-al flags when I call it, which makes the listing a lot more readable:
Here's a sample output:
drwxr-xr-x 28 mattstauffer staff 896 Feb 12 09:46 . drwxr-xr-x 50 mattstauffer staff 2912 Feb 7 14:07 .. -rw-r--r-- 1 mattstauffer staff 18 Aug 21 2017 README.md -rw-r--r-- 1 mattstauffer staff 1286 Dec 20 10:10 package.json drwxr-xr-x 29 mattstauffer staff 928 Jan 14 09:43 source
You can technically ignore all of the columns except the far right column, which is the name of the directory or file. If you want to know whether it's a directory or a file, look at the far left character of the far left column; if it's a
- it's a file, and if it's a
d it's a directory.
The first, third, and fourth columns are about permissions. The second column is basically useless. The fifth (896, etc.) is the file size, in bytes. Then you get the date, and the time, and then the file/directory name.
Installing and using Composer
So, what exactly is Composer? It's primarily a dependency manager. Your project will define its dependencies--the other projects it needs to have access to in order to do its job--and then Composer will install those projects, or packages, and make them accessible to your code.
You'll use a file at the root of your project named
composer.json to define those dependencies, and that will auto-generate a file named
composer.lock that saves the version of the dependencies you installed so you get those same verisons the next time you install.
Let's get Composer installed.
You can find the instructions to download and install Composer on your machine on the Composer Downloads page. If you're working with Windows, there's a special installer which you can learn about in the Composer intro docs.
The goal is that, at the end of this installation process, you can run
composer from anywhere on the command line and it'll work--which means it's "installed globally" and "in your PATH". My hope is that Composer's installation instructions will be enough to get you there, but if you follow them and this following command doesn't work from any directory on your machine, please let me know on Twitter:
Once you have Composer installed, there are a few primary ways you can use it.
Installing an existing project's dependencies
If you clone an existing project that uses Composer, you'll see that it has a
composer.json and a
composer.lock file in it. But if you try to run the project, it probably won't work. The error usually looks something like this:
Warning: require(/Users/mattstauffer/Sites/symposium/bootstrap/../vendor/autoload.php): failed to open stream: No such file or directory in /Users/mattstauffer/Sites/symposium/bootstrap/autoload.php on line 17
That's because it's trying to access the files Composer loads, but you haven't created them yet; those files are ignored in most projects' version control, with the expectation that you're going to use Composer to install them after you clone. So, let's install them! Run this command from your project's root directory:
This command reads
composer.lock and installs all of your required files for you. It'll take a bit, especially the first time you run it, but then your site should just work!
Tip: The files that Composer installs for you go into the
vendordirectory. You may be familiar with NPM and its
node_modulesdirectory. Same deal here.
Adding a dependency to your project
If you need to add a new dependency to your project, or create a project that has a single dependency, you can use
composer require packagenamespace/packagename.
In an existing project, this command will add that package to your
composer.lock files and then install it.
In a new project, that will create your
composer.lock files and add just that package to them.
There's a lot more to learn about the command line and about Composer, but hopefully this is enough to get you up and running with the basics.
- Terminal: An application that lets you access and interact with the command line shell of your computer.
- Command line: An interface with which computer users issue commands to the computer through successive lines of text.
- Shell: The specific interpreter or environment a user is interacting with. By default, on most machines, the command line shell will be BASH.
- BASH: The default command line shell on most machines.
- Composer: A dependency manager for PHP.
cd: Change directory
ls: List files
Comments? I'm @stauffermatt on Twitter
Tags: composer • jigsaw