[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
bug#23185: GNU grep matching discrepancy between -a/--text and not.
From: |
Paul Eggert |
Subject: |
bug#23185: GNU grep matching discrepancy between -a/--text and not. |
Date: |
Tue, 5 Apr 2016 23:56:22 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
Thanks for pointing out the seeming inconsistency. The documentation mentions
the issue but is perhaps not clear enough, so I installed the attached patch.
The input file contains NUL bytes and so is treated as binary data, and the grep
documentation (secton "File and Directory Selection", option "--binary-files")
says "When processing binary data, ‘grep’ may treat non-text bytes as line
terminators". This behavior was added to GNU grep in release 2.21 dated 2014,
partly for performance reasons.
There are two instances in riddle.he of a space followed by a NUL byte, so
grep -P '[ \t]\r?$' riddles.he
finds a match when the $ matches just before the NUL byte.
-a is one way to get the behavior you evidently expected. Another (perhaps
better) way is -z. The command:
grep -zP '[ \t]\r?\n' riddles.he
outputs nothing and exits with status 1.
0001-Give-another-example-of-binary-file-processing.patch
Description: Text Data