Re: grep -e '\(a\)\1' -e '\(b\)\1'

[Tapani Tarvainen]

"Alain Magloire" <address@hidden> writes:

> > multiple -e arguments
> > should be treated as independent patterns and back references
> > should not refer to previous ones.

> I think we can agreed that current behaviour of GNU grep for BRE
> should be fix. 

I must say I'm once again impressed!
No way could I expect that rapid response from any
commercial vendor.

> > echo ba | egrep '(a)\1|(b)\1'   
> > 
> > doesn't print ba either.
> 
> If you are sticking with POSIX.2, For ERE the expression is not
> portable

Agreed. I just find the behaviour in that case surprising:
I'd expect it to match either both aa and ba, or a1 and b1.
Apparently that only matches aa.

-- 
Tapani Tarvainen