From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@labs.coraid.com>
Date: Thu, 14 Jun 2012 10:49:51 -0400
To: 9fans@9fans.net
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Subject: Re: [9fans] empty *
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On Thu Jun 14 10:37:21 EDT 2012, tlaronde@polynum.com wrote:
> On Thu, Jun 14, 2012 at 04:13:12PM +0200, Gorka Guardiola wrote:
> > Also this:
> >
> > cpu%  echo hola | grep '*'
> > grep: *: syntax error
>
> The plan9 regexp are mainly Extended Regular Expression. If the POSIX
> description is taken, a leading '*' is a syntax error. I guess that the
> leading '*' followed by some non empty pattern is a Plan9 way to get
> "grep -F" ?
>
> > cpu%  echo hola | grep ''
> > grep: empty pattern
>
>  From the POSIX description, an empty pattern is not allowed. '*' is not
> an empty pattern.

i'm sorry this just isn't correct.  see the man page.

plan 9 grep has no intentions of being posix.  grep '*' can be seen as a literal
escape plus the pattern of ''.  this is an empty pattern, thus an error.

- erik