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Have you ever wanted to call exit() with an error condition, but weren’t sure what exit status to use? No? Maybe it’s just me, then.
Anyway, I was reading manpages late one evening before retiring to bed in my palatial estate in rural Oregon, and I stumbled across sysexits(3). Much to my chagrin, I couldn’t find a sysexits for Ruby! Well, for the other 2 people that actually care about style(9) as it applies to Ruby code, now there is one!
Sysexits is a completely awesome collection of human-readable constants for the standard (BSDish) exit codes, used as arguments to exit to indicate a specific error condition to the parent process.
It’s so fantastically fabulous that you’ll want to fork it right away to avoid being thought of as that guy that’s still using Webrick for his blog. I mean, exit(1) is so passé! This is like the 14-point font of Systems Programming.
Like the C header file from which this was derived (I mean forked, naturally), error numbers begin at Sysexits::EX__BASE (which is way more cool than plain old 64) to reduce the possibility of clashing with other exit statuses that other programs may already return.
The codes are available in two forms: as constants which can be imported into your own namespace via include Sysexits, or as Sysexits::STATUS_CODES, a Hash keyed by Symbols derived from the constant names.
Allow me to demonstrate. First, the old way:
exit( 69 )
Whaaa…? Is that a euphemism? What’s going on? See how unattractive and… well, 1970 that is? We’re not changing vaccuum tubes here, people, we’re building a totally-awesome future in the Cloud™!
include Sysexits exit EX_UNAVAILABLE
Okay, at least this is readable to people who have used fork() more than twice, but you could do so much better!
include Sysexits exit :unavailable
Holy Toledo! It’s like we’re writing Ruby, but our own made-up dialect in which variable++ is possible! Well, okay, it’s not quite that cool. But it does look more Rubyish. And no monkeys were patched in the filming of this episode! All the simpletons still exiting with icky numbers can still continue blithely along, none the wiser.
At some point, Apple started including their own sysexits library in vendor_ruby, so to load the gem version on a MacOS X 10.7+ box, you need to do:
gem 'sysexits'
require ‘sysexits’
It’s a bit ugly, but there isn’t a whole lot I can do about it. Sorry.
You can clone the source with Mercurial, submit bug reports, suggestions, etc., via the project page:
https://bitbucket.org/ged/sysexits
Or if you prefer Git, you can clone the source via its Github mirror:
https://github.com/ged/sysexits
After checking out the source, run:
$ rake newb
This task will install any missing dependencies, run the tests/specs, and generate the RDoc.
You can read more super-exited pointless marketing at:
http://deveiate.org/sysexits.html
Or maybe not.
Copyright © 2010-2012, Michael Granger All rights reserved.
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