Re: OT: grep for \x00 = NUL

Re: OT: grep for \x00 = NUL

[Brian Dessent]

fergus wrote:

>         grep $'\x0d' # e.g. equivalent to grep "^M"

Using that method you're passing the literal character to grep through a
bash quoting mechanism.  You can't pass a literal NULL as part of a
command line because argv[] consists of NULL-delimited strings, as do
most C string functions.

Why not just tell grep to look for a NULL rather than trying to feed it
an actual literal NULL character?

$ grep -P '\000'

In pcre regexps you can use \nnn to match any character represented by
octal nnn.  This would work for any character, and it doesn't rely on a
bash-specific shell feature.  But it does rely on grep supporting -P for
pcre, which is not universal.  If that cannot be relied on then you can
use

$ perl -ne 'print if m/\000/'

or

$ awk '/\000/ { print }'

Brian

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fftw library

[javier sacristan]

Hi, and thanks for your help, I would like to know if someone has already
installed a FFTW library to perform Fourier transforms. If so, could you
explain me how to do it?

Thank you


Javier



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