Ed Wildgoose writes:
The regex part. I agree it's standard regex syntax, but the docs
*suggest* that maildrop doesn't support standard (full) regexp.
It's a little frustrating trying to guess exactly which bits of grep
regexp are supported and which are not.
Ummmmm, STANDARD regexp syntax? GREP regexp syntax? Sorry guys, see
Friedl's "Mastering Regular Expressions" - there's no standard syntax.
Various tools (grep, exp, sed, perl) use differing syntaxes. Different
versions of those tools (such as perl 4, perl 5 and perl 6) use differing
syntaxes. Different alternative derivations of those tools (grep vs gnu
grep) use different syntaxes.
And just to make life even more complicated, the underlying regexp engine
can mean that some regexps will take close to infinite time to complete.
If you don't know what's underneath the hood you can really ruin your day.
When it comes to regexps with any particular tool, you can only trust what
the docs for that tool say you can trust. Other things may work, but
you're on thin ice because something that is documented is less likely to
change than something that is undocumented. YMMV, etc.