Re: "tr -d string1 string2" POSIXLY_CORRECT simplification

[Paul Eggert]

Jim Meyering <address@hidden> writes:

>     * When the -c option is specified with -d, all values except those
>     specified by string1 shall be deleted. The contents of string2 shall be
>     ignored, unless the -s option is also specified.

Yes, that text is pretty confusing, since it seems to imply that "tr
-cd string1 string2" is allowed (otherwise, why would "string2" be
allowed?).  However (putting my pedantic hat on, which after all is
the point here :-) a conforming application must conform both to this
text and to the SYNOPSIS, and therefore a conforming application
cannot use "tr -cd string1 string2" at all.

OpenBSD and FreeBSD both reject "tr -d string1 string2" (with or
without -c), and they both claim conformance to POSIX, so there is
some precedent for this interpretation.

I think the above wording is a defect in POSIX and I suppose someone
should submit a defect report....

> I don't think anyone will notice the change.

Likewise.