regex - Regular Expression up to but do not include character -

this has been done before , have tried customize regex based on other entries in stack exchange having hard time grasping it...

what need match query string parameter in rewritecond , take parameter value of cond , insert in new string.

my cond is:

wt.mc_id=(\s+&|\s+$)

this gives me close need. not want & in %1 value rewriterule.

so when gives me wt.mc_id=foo&bar=whatever want foo, not foo&. don't want empty string can check in code.

use regex instead:

(^|&)wt\.mc_id=([^&]*)

Brazell