Re: [patch #10070] toggle invert flag when reading `!'

[Chet Ramey]

On 5/27/21 11:20 AM, Andreas Schwab wrote:
> On Mai 27 2021, Chet Ramey wrote:
>
> > On 5/26/21 9:55 PM, Dale R. Worley wrote:
> >
> > > >     $ ! ! [ 1 -eq 1 ]; echo $?
> > > >     0
> > > That last one isn't defined by the manual page.  I'm surprised you don't
> > > get a syntax error.
> >
> > It's clearly valid.
>
> According to the POSIX grammar, a pipeline can only be a pipe_sequence
> optionally preceded by a single Bang.  If you want another Bang the
> pipe_sequnce needs to be either a subshell or a brace_group.

True, but bash accepts it. (So do ksh and mksh; dash and yash do not.)


--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/