Progress Bars & Spinners

You've arrived at one of my favorite pages, the magical world of progress bars and spinners. I love the little details, the flourish that makes cli fun. Aren't these things supposed to be fun?

It is pretty easy to add a progress bar or spinner to virtually any cli app these days. Libraries abound, often with easy-to-use APIs and color support. Even if your favorite library is a bit dated, you can probably find a way to make it pretty.

My rule of thumb is that any operation that takes more than a second deserves a progress bar. Why make the user wait? Modern progress will often display a nice ETA before finally morphing to "elapsed time" when the operation completes. Free logging! Seriously, apply liberally.

I look to rich as a baseline of sorts for Progress Bar Technology:

Here are the features that I like to consider when selecting a library:

Under The Hood

Creating progress bars and spinners from scratch is pretty easy. These libraries write a line of text (no newline), then emit a \r to move back to the first column and do it again. Simple, which probably explains why there are 10,000 different libraries out there.

A key detail that some libraries overlook is to use the ANSI show/hide cursor escape codes to make the terminal cursor disappear for a bit. See ANSI Escape Codes for hints on that one.

Libraries

Typically in ansi.md I try to only recommend libraries that I personally have tried. This is a tough table for me because I haven't used progress bars across that many languages yet. Chicken emoji below means I've used and enjoyed. 🐔

If you have opinionated recs please send 'em.