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Re: Bug in grep.exe
From: |
Eli Zaretskii |
Subject: |
Re: Bug in grep.exe |
Date: |
Sat, 26 Aug 2017 14:04:58 +0300 |
> From: Nicholas Hawthorn <address@hidden>
> Date: Sat, 26 Aug 2017 12:03:58 +1200
>
> Say we make a one line text file called "a" that contains
> w CR LF
>
> and then give the command:
> grep -v "<" < a > b
>
> File "b" will consist of:
> w LF
>
> In effect, grep has removed the CR.
Yes, and this is a feature. The exact command-line arguments are
unimportant: Grep on Windows _always_ strips CR characters from
Windows-style CRLF EOLs, and never adds them back when writing output
to files or pipes. This is because the alternative, of always adding
CR to LF-only Unix-style EOLs, which is what Windows text-mode output
would do, is much worse and will break many scripts and test suites.
It would also make it impossible to output anything past the first ^Z
byte, which serves as a "software EOF" indicator.
> The bug was first found in a 66 line .bat file where it was a bit of
> a nuisance.
Why is that a problem in a batch file? AFAIK, the stock Windows shell
in modern versions of MS-Windows has no problems running batch files
with Unix-style LF-only EOLs, unlike on old versions of the OS.
P.S. I think (but I'm not sure) latest versions of Grep removed this
feature, so perhaps you will be better off if you upgrade your Grep
installation.
- Bug in grep.exe, Nicholas Hawthorn, 2017/08/26
- Re: Bug in grep.exe,
Eli Zaretskii <=