find regular expression question

[Zak Johnson]

Volodymyr Kostyrko wrote:
>   Just stumbled upon some inconsistences in find(1) regular expressions 
> parsing:
> 
> [code]
> > :>a
> > find . -regex '^\./a\?$'
> > find . | grep '^\./a\?$'
> ./a
> [/code]

Find uses basic (obsolete) regular expressions by default; '?' is an
ordinary character.  You can use either of the following instead:

find . -regex '^\./a\{0,1\}$'
find -E . -regex '^\./a?$'

find's '-E' option makes -regex use the extended regular expression
syntax, documented in re_format(7).  GNU grep uses its own---slightly
different---re syntax, described in grep(1).

-Zak