How to use grub regex?

[Mat Troi]

Hi,

I want to find out if a string contain certain word in grub.  I am thinking about using grub regex.

Problem:

set string = (hd0,gpt1)/blah/blah

I want to find if cd is in string, how do I do that?

I tried "regex --set=foo 'cd' $string

echo $foo

There isn't anything in foo, so I guess my regex is not correct.

Thanks,

MT