adding a crlf

Trying to format a file by adding a crlf at every Nth position in a
file. Not sure what is the best way to do this and looking for ideas
of how to do it. I am currently running a process in ANT to handle
the file and was hoping that I could achieve this by using an already
existing ANT task ( replace?, replaceregexp?)

example of data in file:
some text in file that goes like this and keeps going with no returns
in it but i want to add some to reformat the file.

what i would want the output to be after processing - by adding a
crlf after every 10th character in the file:
some text
in file t
hat goes l
ike this a
nd keeps g
oing with
no return
s in it bu
t i want t
o add some
to reform
at the fil
e.

=====================
thanks
tmw
.