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FreeBSD
pkg_add -r postgresql82-server
The package creates a 'pgsql' user account.
Change to that user to finish the installation:
su -m pgsql
Initialize the database:
/usr/local/bin/initdb /usr/local/pgsql/data
Create a user:
/usr/local/bin/createuser USERNAME
Log out of the 'pgsql' user account by pressing
[CRTL]+d
or
lo
At this point the PostgreSQL daemon can be started.
/usr/local/etc/rc.d/postgresql start
To have PostgreSQL start automatically with FreeBSD you need to add this line to /etc/rc.conf
postgresql_enable="YES"