grep regex whitespace behavior

Question

I have a textfile, containing something like:

12,34 EUR   5,67 EUR  ... 

There is one whitespace before 'EUR' and I ignore 0,XX EUR.

I tried:

grep '[1-9][0-9]*,[0-9]\{2\}\sEUR' => didn't match !

grep '[1-9][0-9]*,[0-9]\{2\} EUR' => worked !

grep '[1-9][0-9]*,[0-9]\{2\}\s*EUR' => worked !

grep '[1-9][0-9]*,[0-9]\{2\}\s[E]UR' => worked !

Can somebody explain me pls, why I can't use \s but \s* and \s[E] matched?

OS: Ubuntu 10.04, grep v2.5

Answer 1

This looks like a behavior difference in the handling of \s between grep 2.5 and newer versions (a bug in old grep?). I confirm your result with grep 2.5.4, but all four of your greps do work when using grep 2.6.3 (Ubuntu 10.10).

Note:

GNU grep 2.5.4 echo "foo bar" | grep "\s"    (doesn't match) 

whereas

GNU grep 2.6.3 echo "foo bar" | grep "\s" foo bar 

Probably less trouble (as \s is not documented):

Both GNU greps echo "foo bar" | grep "[[:space:]]" foo bar 

My advice is to avoid using \s ... use [ \t]* or [[:space:]] or something like it instead.