Quick and dirty way to migrate user accounts from one FreeBSD box to another. From the source box you will only need two files:
copy them to the target box, but DON’T overwrite (yet) the existing files there. Put them in /root/master.passwd and /root/group. Compare the copied files with the existing ones for new system users that may exist. If there are any new users/groups add them to the copied files.
Then move /root/group to /etc/group and run this magical command
pwd_mkdb -p /root/master.passwd
It will install in /etc/master.passd and recreate all the needed files (/etc/pwd.db, /etc/spwd.db and /etc/passwd).