Get File MIME Type from Command Line
I've gotten skilled at shell scripting over the years. I love a good GUI but knowing how to automate makes you a much more powerful engineer. Much of my scripting requires recursing over directories and processing a file if it meets a given criteria, which is often file extension or MIME type.
You can use the following shell command to get a file's MIME type:
file --mime-type -b Downloads/main.js
# text/plain
file --mime-type -b Downloads/logo.jpg
# image/jpeg
It's important to use the brief (-b) option in the command or you may receive an error message.
MIME type is used for validation and any number of other informational use cases. Luckily the file command and and a flag is all you need!
![Page Visibility API]()
One event that's always been lacking within the document is a signal for when the user is looking at a given tab, or another tab. When does the user switch off our site to look at something else? When do they come back?
![Detect DOM Node Insertions with JavaScript and CSS Animations]()
I work with an awesome cast of developers at Mozilla, and one of them in Daniel Buchner. Daniel's shared with me an awesome strategy for detecting when nodes have been injected into a parent node without using the deprecated DOM Events API.
![Degradable SELECT onChange]()
Whenever I go to Google Analytics I notice a slight flicker in the dropdown list area. I see a button appear for the shortest amount of time and the poof! Gone. What that tells me is that Google is making their site function...
![Do / Undo Functionality with MooTools]()
We all know that do/undo functionality is a God send for word processing apps. I've used those terms so often that I think of JavaScript actions in terms of "do" an "undo." I've put together a proof of concept Do/Undo class with MooTools.
The MooTools...