Inconsistent regex matching with =~ between bash 3.1 and 3.2

[Scott Carpenter]

Hi, all.  I hope this report is of some use -- I'm pretty inexperienced 
at GNU/Linux and Bash so I'm afraid this is going to sound horribly 
amateurish.  But I think I've found something for you.  (Or I'm simply 
about to demonstrate my crude understanding of regular expressions.)

I realize that regex handling has changed for the =~ operator from 3.1 
to 3.2, and I'm trying to get my head around this while fixing a script 
that has broken in 3.2.  I studied this thread:

http://www.nabble.com/Conditional-Regexp-matching-problem-in-3.2-t3040946.html

And other pages and think I understand how I'm supposed to do things in 
3.2, and can make my script work in 3.2.  I'd like to make it be 
backwards compatible for 3.1, but I get different results for the 
example shown below (and errors on a variation).

In Ubuntu 7.04, $BASH_VERSION 3.2.13(1)-release, I try:

V="one/two"
[[ ! $V =~ ^\.*/ ]] && echo not

And get "not", as expected. (The first part is true.)

In Ubuntu 6.10, $BASH_VERSION 3.1.17(1)-release:

The first part doesn't evaluate as true, so no output.

And this comes out as true:

[[ $V =~ ^\.*/ ]]

So, either my regex is all wrong (I'm trying to match from a dot at the 
start of the string up to the last forward slash), or might there be a 
problem with this 3.1 version of bash?  Or door #3?

3.1 works as I expect if I try ^\./ as the regex (string starting with 
dot slash).  (That is, it matches with ! for "one/two".)

Finally!

The following works in 3.2 (produces "yes" for "./one/two"), but gets an 
error in 3.1:

[[ $V =~ (^\.*/) ]] && echo yes

unexpected argument `(' to conditional binary operator
syntax error near `(^'

Please let me know if more info would help.  Again, I hope this is 
helpful, or at least isn't extremely annoying, and I apologize if it 
isn't/is.

Scott