Re: [bug #14946] "grep -P" doesn't support pattern lists

[Julian Foad]

Charles Levert wrote:
> Would replacing each newline character in the aggregated pattern by a
> vertical line character do the trick?  Just as the tricks that are used to
> support -w and -x, this can be abused by a user who intentionally feeds in an
> invalid pattern or pattern list (e.g., "echo 'x y z' | grep -P -w --color 'x)
> y (z'").

I imagine that would work iff "|" is the lowest-precedence operator supported 
by Perl regexps (and means alternation as in EREs).  I don't know anything 
about them.

I don't understand what your example command demonstrates.

- Julian