[ANN] Subprocess: a library for launching and communicating with Unix commands

Ecosystem
1

An OCaml library with documentation!?

Yes. I realize it’s unorthodox, but I thought I’d give it a shot.

I began my programming journey a bit later than most, and I began it with Bash. Over the years I’ve grown apart from Bash and even written some semi-popular anti-Bash propaganda.

However, while I’m not particularly a fan of shell programming languages, I’ve maintained a long-term interest in the types of automation tasks which the shell lends itself to, and I have a soft spot in my heart for languages which make this type of programming a priority—languages such as AWK, Perl and Ruby.

Since learning OCaml, I always felt that it could be a good language for these kinds of jobs with its light syntax, extensive Unix interface and great regex libraries (I’m talking about Re and friends, not Str).

However, I always felt the provided interfaces for working with processes were… not quite what I was looking for. Sys.command (combined with Filename.quote_command, of course) is OK for what it does, but it doesn’t do much. The more extensive set of process handling commands in the Unix library make just about anything possible, but they don’t feel good to me.

So I set out to create a library for working with Unix commands which feels right to me. Subprocess focuses on safety and ease of use—in that order. I hope someone besides myself will feel the same about it.

Note that this is the first release (and my first public OCaml library) and I welcome feedback and criticism.

Github: GitHub - ninjaaron/ocaml-subprocess: Simplified interface to using Unix commands with OCaml
Opam: subprocess 0.2.1 (latest) · OCaml Package
Odoc docs: index (subprocess.index)

14 Likes
2

Looks interesting- thanks for creating / sharing it! Are you familiar with janestreet’s shexp which I think is trying to solve a similar problem?

1 Like
3

No, but thanks for sharing it! I admit with some shame that I didn’t do much research on alternatives before writing this library because I really wanted to write it. :sweat_smile:

It looks very cool, though, and I will definitely be giving it a test drive.

2 Likes
4

If you could compare it to feather too, I’d be most interested in your findings! (it’s on my list to try too, but won’t probably get to it for a while).

I’ve seen that you’ve got stars already - you look like a legit Ninja :smile: Congrats!

5
  • Another library, but with a different design philosophy, is Bos.
  • I notice that Subprocess uses Unix.select. This imposes an upper limit on the number of file descriptors an application can use to 1024, which can be a problem in server applications.
4 Likes
6

It’d be nice to see an example of some simple shell script demonstrating salient shell features translated into all the different libraries discussed above: subprocess, shexp, feather, and bos.

2 Likes
7

Good to know! I updated the code on github to remove select, though I have not made a new release to opam yet.

8

It’s a surprise to me, too! I’ve been working on this library for a while and the git repository was always public, but I’m pretty sure it only had one star when I went to bed last night—but stars aren’t too hard to come by if you build anything remotely usable. The real test is the number of forks!