How to change the decimal separator with awk/sed?

Question

How to change number format (different decimal separator) from XXXXXX.XXX to XXXXXX,XXX using sed or awk?

Answer 1

Wouldn't this be more accurate as the OP whas talking about numbers.. to make sure it is a leading number before the dot. The document could hold other dots that the OP don't want to substitute.

sed '/[0-9]\./s/\./,/g'