Re: "grep -o" skips some matching patterns

[Stepan Kasal]

Hello,
        thank very much to Michael for the explanation, which helped.

I'd like to add a theoretical comment which won't help at all ;-)

On Tue, Dec 30, 2003 at 04:24:23PM +0100, Roberto Gordo Saez wrote:
> $ echo abc0111def | grep -o "[01]*"

This command should in fact print seven lines, three empty ones,
then the non-empty match and another three empty ones.
The reason can be explained by the following (the sed command performs
global substitution of your regex by "(...)"):

$ echo abc0111def|sed 's/[01]*/(&)/g'
()a()b()c(0111)d()e()f()

So you have actually triggered a bug in ``grep -o''.

I hope to help with fixing it...

Stepan Kasal