Maybe you want something like this:

/
   ^(?![ ])        # Doesn't start with a space
   .*?             # Anything
   [a-z0-9]{5,12}  # Has a 5..12 lowercases or digits in a row
   .*              # Anything
   (?<![ ])$       # Doesn't end with a space
/x

[download]

which will match
a1b2c3
BVBDa1b2c3
a1b2c3ZZZ
!@#a1b2c3$%^
! a1b2c3 FF

In reply to Re: Regex: Specifying quantity for bracketed items by ikegami
in thread Regex: Specifying quantity for bracketed items by Hagbone

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