I’ve often written about how powerful and useful Emacs calc can be1. It is, I think, one of the most underrated features of Emacs. It’s a bit hard to learn, not because its default data entry mode is RPN but because it’s so powerful and has so many functions. I’ve sometimes described it as “a poor man’s Mathematica.” That comparison is overblown, of course, but for most people, calc can do everything that they’re apt to need in the way of mathematical calculations.
Christoffer Stjernlöf has a cute trick: he’s released a shell script that lets you run calc without explicitly opening Emacs. It works just the way you’d think it would. It starts Emacs in the background and calls calc from the command line. A very nice little hack.
It’s great for people who aren’t Emacs users but would like to take advantage of calc’s power. You don’t need to know any Emacs arcana to use calc so that’s a valid use case. On the other hand, I’m not sure how useful it is for Emacs users. Most of us always have Emacs running and many of us have a shortcut to start up calc. For example, I have F10 mapped to calc-dispatch so a single key starts calc for me.
Still, I’m sure there are people, some of them Emacs users, who will find the script useful. If you aren’t already a calc user you really should become one. You’ll find it worth the effort, I promise.
Footnotes:
There’s too many to list. Do a search on “emacs calc” to get an idea of how often I’ve written about it. Even I was surprised at the number of posts involving calc.