On Tue, Dec 16, 2014 at 09:36:33AM +0000, Pedro Alves wrote:
> On 12/15/2014 11:00 PM, Sergio Durigan Junior wrote:
> > +# Check if grep supports the '--text' option.
> > +
> > +GREP_TEXT_OPT="--text"
> > +if grep --text 2>&1 | grep "unrecognized option" > /dev/null 2>&1 ; then
> > + GREP_TEXT_OPT=""
> > +fi
> > +
>
> That assumes all greps output "unrecognized option" on
> unrecognized options. I don't think that can be counted on being
> portable? ISTM reversing the logic of the test would be better.
> IOW, test that --text actually works. Something like this perhaps:
>
> # If grep supports the '--text' option, use it.
> GREP_TEXT_OPT=""
> if echo foo | grep --text foo > /dev/null 2>&1 ; then
> GREP_TEXT_OPT="--text"
> fi
Even better include some non-text bytes around the foo string in the input you
feed to grep.
Also, perhaps better would be to use a GREP variable, initialized to
GREP=grep
or
GREP="grep --text"
and just invoke $GREP.
Jakub
