From: Alex Waite <alexqw85@gmail.com>
To: dash@vger.kernel.org
Subject: Pattern matching faster than math
Date: Wed, 25 Mar 2015 14:51:56 +0100 [thread overview]
Message-ID: <meuehs$n4e$1@ger.gmane.org> (raw)
Hello,
This isn't a problem per-se, but I'm curious if anyone can shed some
light on why this is so.
I have a script where I'm checking if the contents of a variable is an
integer. An easy/hacky way to do this is
[ "$var" -ge 0 2> /dev/null ] || echo "is not int"
But this caused posh to segfault, so I went for a pattern matching
solution instead:
[ -z "${var##*[!0-9]*}" ] && echo "is not int"
This works well, and it makes posh happy. But what's surprising to me is
that it's faster.
I have more of a write-up in a commit message:
https://github.com/zfsnap/zfsnap/commit/ed6326f0006ed18b7d8bb79d5ee8f06142847f41
Any thoughts or insight? Am I making some faulty assumption here?
Thanks for your time.
---Alex
reply other threads:[~2015-03-25 13:52 UTC|newest]
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