What's the difference between cat /etc/group and cat /etc/group- [duplicate]

Question

Possible Duplicate:
What's the difference between the “group” and “group-” file?

I just changed a group name and noticed that

cat /etc/group

Includes the updated group name, but

cat /etc/group-

includes the old group name. How are the group and group- files different?

Answer 1

It is just a backup file that groupadd and similar programs use to store the previous state of the group file.