Re: regexp bug in sed/grep?

[Stepan Kasal]

Hello,

On Mon, Sep 30, 2002 at 11:26:08AM +0900, Miles Bader wrote:
>    $ echo pqrABx | sed -e 's/AB*x?$//'
>    $ echo pqrABx | grep 'AB*x?$'

in addition to the explanation by Bob Proulx, I'd like to say that with
gnu versions of sed and grep, you can escape the ? with backslash to get
the metacharacter.  So 'AB*x\?$' should work in these cases.

As the grep manual puts it:

| `grep' understands two different versions of regular expression syntax:
| "basic" and "extended".  In GNU `grep', there is no difference in
| available functionality using either syntax.  In other implementations,
| basic regular expressions are less powerful.  The following description

HTH,    
        Stepan Kasal