Using just

When your old friend Makefile leaves you hanging…enter just.

What is just

just is just a command runner with a syntax inspired by make that helps you, well, run commands. That’s it.

Why

I am used to using Makefile in my personal projects and I really like it. It has a simple syntax and works well whenever we don’t want to keep writing the same command over and over again. It also helps you create the recipes that make the whole process of, for example, running a project that needs to be tested and built before, a piece of cake.

But, as fate has a sense of humour, while creating this repository to post some notes about life and tech, I stumbled upon the problem of using Makefile to automatise the creation of my posts.

I wanna be able to run a command, at that time something like make post post_name and it would create a post template file for me, with the timestamp and the name defined. The problem is that I can’t do it in this way, I would have to write make post NAME=post_name in order for it to work. And I did not want it. Too bloated for my likings.

Another obstacle was to get the current timestamp. Doing $(date -u +%Y-%m-%d) would not work in a Makefile and I did not do my research to find out how (if) to do that.

My Makefile was looking like this:

# "new content in 'content/posts/date-<title>'.md"
.PHONY: post
post:
 hugo new -k post content/posts/$(date -u +%Y-%m-%d)-$1.md

Don’t get me wrong, it would work just (😁) fine if I would pass the post name as an environment argument:

# "new content in 'content/posts/date-<title>'.md"
.PHONY: post
post:
 hugo new -k post content/posts/$(date -u +%Y-%m-%d)-$(NAME).md

but with the date I was not sure (and did not want to do that research).

Perks of just

Well, I’ve only used it now and only the basic stuff, but it already got my heart.

Using as an example the Makefile above, we can write it in just - using a .justfile - like this:

# new content in 'content/posts/date-<title>'.md
post NAME:
  hugo new -k post "content/posts/$(date -u +%Y-%m-%d)-{{NAME}}.md"

And run it with just post post_name.

Wonderful, right?

And, if you run just --list, it gives you a summary of all available recipes, along with their comments.

$ just --list
Available recipes:
    post NAME   # new content in 'content/posts/date-<title>'.md

If you don’t want to run just --list every time, you can add to the .justfile as the first recipe:

default:
  just --list

And now, every time you run just, it will print all available recipes.

The first recipe of the justfile will be run when you use just without arguments.

Another great thing is that you can simplify your recipe namings by using aliases:

alias p := post

If you ran just p post_name it will have the same effect as just post post_name.

Conclusions

Give it a try. I think it’s worth it.

License

This post is licensed under Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International.