regular expression to match repeated appearance

Hi all,

I am looking for a regex syntax to match repeated appearance. Likes,

'[[:alnum]]+[[:alnum:]]+' matches for string '65A SOME MORE AND 78B'

Now, this gets messy if I need to extract all such repeated appearance. I don't want to write [[:alnum:]] four or five times for matching repeated appearance.

Thanks in advance.

---------- Post updated at 07:56 PM ---------- Previous update was at 07:43 PM ----------

Basically, I am looking at extracting all alpha numeric from the string. Doesn't matter how many times it appears in the string.

Can you post the input file and the desired output between code tags?

Contents of test.file

68A some text here 89B some other text here.
new line here, 12A on second line 34B
some lines may have 12B and 56F and 67C and so on 23

Now, I need to read each line, compare them with regular expression '[[:alnum:]]' to fetch the string alpha numerics into a variable.