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Re: Incorrect example for `[[` command.
From: |
Ilkka Virta |
Subject: |
Re: Incorrect example for `[[` command. |
Date: |
Sat, 21 Sep 2019 12:34:39 +0300 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 |
On 21.9. 03:12, hk wrote:
Thanks for the reply. I was wrong in my report. It does match values like
aab and aaaaaab in its original form.
In some systems, yes. (It does that on my Debian, but doesn't work at
all on my Mac.)
It is syntatically correct as a regular expression.
[[:space:]]*?(a)b isn't a well-defined POSIX ERE:
9.4.6 EREs Matching Multiple Characters
The behavior of multiple adjacent duplication symbols ( '+', '*', '?',
and intervals) produces undefined results.
https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/basedefs/V1_chap09.html
--
Ilkka Virta / itvirta@iki.fi