Re: grep: return code with -v and empty input

[Alain Magloire]

> 
> address@hidden (Edward Avis) writes:
> 
> > According to the documentation, the -v flag is supposed to invert the
> > exit status:
> > 
> > >Normally, exit status is 0 if matches were found, and 1 if no matches
> > >were found (the `-v' option inverts the sense of the exit status).
> 
> > However it doesn't seem to work like that for empty input.
> 
> > I suspect this may be a documentation bug; perhaps it should say
> > something like:
> > 
> > 'If the -v flag is given, then a "matching line" is one which does _not_
> > match the pattern.  The exit status is still 0 if there were no
> > "matching lines" and 1 if there were some.'
> 
> That is indeed the way it is supposed to work according to POSIX.2:
> 
> "
>     -v          Select lines not matching any of the specified patterns.
> ...
> 
>  The grep utility shall exit with one of the following values:
> 
>      0    One or more lines were selected.
> 
>      1    No lines were selected.
> 
>     >1    An error occurred.
> "
> 
> Clarifying the documentation might be in order.

grep.info and man page:
Diagnostics
***********

   Normally, exit status is 0 if selected lines are found and 1
otherwise.  But the exit status is 2 if an error occurred, unless the
`-q' or `--quiet' or `--silent' option is used and a selected line is
found.


Is this not clear?

-- 
au revoir, alain
----
Aussi haut que l'on soit assis, on est toujours assis que sur son cul !!!