Is there any reason to prefer [[ over [ in bash?

Asked Jun 08 '15 at 06:49

Active Jun 08 '15 at 06:49

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I used to think [ would spawn /usr/bin/test and [[ was a builtin, but apparently, it doesn't:

$ strace bash -c " [ -z "$FOO" ] && echo yes " 2>&1 | grep test

and

$ type [
[ is a shell builtin

[ is a shorter and seems more portable too. I'm on GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu).

asked Jun 08 '15 at 06:49

Petr Skocik

http://mywiki.wooledge.org/BashFAQ/031 – jasonwryan Jun 08 '15 at 06:57
Ok, so TL;DR: no, unless I'm using one of the special features of [[. Great link +1, @jasonwryan! – Petr Skocik Jun 08 '15 at 07:01
I think you misread the page: if your shebang is bash, you should always prefer [[ over [. – jasonwryan Jun 08 '15 at 07:04

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