[ANNOUNCEMENT] Updated: grep-2.6.3-1

Henry S. Thompson ht@inf.ed.ac.uk
Fri Aug 27 14:24:00 GMT 2010

cgf wrote:

> Note that [now] grep opens files in binary mode for both reading and writing
> so the output of grep will always have \n endings unless you specify the
> --binary option which will (perhaps paradoxically) force the output to
> reflect exactly what was in the file being grepped.

For those of us who only RTFM [1] when forced to, I learned the hard way
that the mapping of \r\n to \n implied above actually happens on
_input_, so many patterns involving \r will fail w/o --binary.

You have been warned.


[1] The online documentation reads:

  By default, under ms-dos and ms-Windows, grep guesses the file type
  by looking at the contents of the first 32kB read from the file. If
  grep decides the file is a text file, it strips the CR characters
  from the original file contents (to make regular expressions with ^
  and $ work correctly). Specifying [--binary] overrules this
  guesswork, causing all files to be read and passed to the matching
  mechanism verbatim; if the file is a text file with CR/LF pairs at
  the end of each line, this will cause some regular expressions to
  fail. This option has no effect on platforms other than ms-dos and
       Henry S. Thompson, School of Informatics, University of Edinburgh
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 651-1426, e-mail: ht@inf.ed.ac.uk
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