Regex help

Hi, I know this is pretty easy to do but I am horrorable at working with regular expressions and was wondering if anybody might take a min to help please. I will have a variable: $the_extention which will have a value like: 98797-234234--2c-something-2c How do I take out the part which will always start with "--2c" and will always end with "-2c" eg: Using the above variable I want to do something like $second_extention= use_regex_here($the_extention) (value of $second_extention becomes: 98797-234234) A good "baby steps" tutorial on regex too would be appreciated. Thanks in advance, Cheers, -Ryan