Re: grep: RE error in ^*** ADVICE-ON-FAILURE-: repetition-operator operand invalid

[Gregory Heytings]

> > I just checked, it was not incorrect.  POSIX says that in BREs the '*' 
> > is special, except wen used:
> >
> > - in a bracket expression
> > - as the first character of an entire BRE (after an initial '^', if any)
> > - as the first character of a subexpression (after an initial '^', if any)
>
> That just means that the first of the three asterisks is literal. The 
> other two are special and indicate repetition of the literal asterisk.

Hmmm, you're correct. '^**' would be correct (matching zero or more 
asterisks), but '^***' is not, because POSIX also says that "multiple 
adjacent duplication symbols produces undefined results".

> (And even if the three asterisks were interpreted literally, it would be 
> bad style.)

It's better if the expression is correctly matched by more grep's, indeed. 
Anyway, bug closed.