Concatenating JavaScript
I generally try and distance myself from unnecessary project overhead, mostly in the form of extra tools hanging around. For that reason, I really never fell in love with task runners like Grunt and Gulp, but at the same time I see a lot of value in what they do.
One of the major things I do on a project is JavaScript concatenation (and minification), so I was happy to stumble upon this:
cat *.js > app.min.js
Running that on the command line will concatenate your JavaScript files. Nice little thing to have in your tool belt if you're looking to keep things simple.
This plus a Sass --watch
gets me about 90% of the way on most projects.