A surprising benefit of command/program completion in my shell

September 25, 2016

I've recently been experimenting with a variant of my usual shell that extends its general (filename) completion to also specifically complete program names from your $PATH. Of course this is nothing new in general in shells; most shells that have readline style completion at all have added command completion as well. But it's new to me, so the experience has been interesting.

Of course the obvious benefit of command completion is that it makes it less of a pain to deal with long command names. In the old days this wasn't issue because Unix didn't have very many long command names, but those days are long over by now. There are still a few big new things that have short names, such as git and go, but many other programs and systems give themselves increasingly long and annoying binary names. Of course you can give regularly used programs short aliases via symlinks or cover scripts, but that's only really worth it in some cases. Program completion covers everything.

(An obvious offender here is Google Chrome, which has the bland name of google-chrome or even google-chrome-stable. I have an alias or two for that.)

But command completion turned out to have a much more surprising benefit for me: it's removed a lot of guesswork about what exactly a program is called, especially for my own little scripts and programs. If I use a program regularly I remember its full name, but if I don't I used to have to play a little game of 'did I call it decodehdr or decodehdrs or decode-hdr?'. Provided that I can remember the start of the command, and I usually can, the shell will now at least guide me to the rest of it and maybe just fill it in directly (it depends on whether the starting bit uniquely identifies the command).

One of the interesting consequences of this is that I suspect I'm going to wind up changing how I name my own little scripts. I used to prioritize short names, because I had to type the whole thing and I don't like typing long names. But with command completion, it's probably better to prioritize a memorable, unique prefix that's not too long and then a tail that makes the command's purpose obvious. Calling something dch might have previously been a good name (although not for something I used infrequently), but now I suspect that names like 'decode-mail-header' are going to be more appealing.

(I'll have to see, and the experiment is a little bit precarious anyways so it may not last forever. But I'll be sad to be without command completion if it goes.)

Written on 25 September 2016.
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Last modified: Sun Sep 25 01:56:35 2016
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