# install
yum -y install postgresql

service postgresql start
# or
/etc/rc.d/init.d/postgresql start

# usage
psql template1

pg_dump dbname > outfile
# Restoring the dump
psql dbname < infile

pg_dumpall
# Restoring the dump
psql -f infile postgres

[root@box ~]# su - postgres
-bash-3.1$ psql template1
postgres=# \q

GRANT { { SELECT | INSERT | UPDATE | DELETE | RULE | REFERENCES | TRIGGER }
    [,...] | ALL [ PRIVILEGES ] }
    ON [ TABLE ] tablename [, ...]
    TO { username | GROUP groupname | PUBLIC } [, ...] [ WITH GRANT OPTION ]
...
GRANT role [, ...] TO username [, ...] [ WITH ADMIN OPTION ]
###
REVOKE [ GRANT OPTION FOR ]
    { { SELECT | INSERT | UPDATE | DELETE | RULE | REFERENCES | TRIGGER }
    [,...] | ALL [ PRIVILEGES ] }
    ON [ TABLE ] tablename [, ...]
    FROM { username | GROUP groupname | PUBLIC } [, ...]
    [ CASCADE | RESTRICT ]
###
CREATE ROLE name [ [ WITH ] option [ ... ] ]
CREATE USER name;
createuser [option...] [username]
# createuser is a wrapper around the SQL command CREATE ROLE. 

### Examples
CREATE ROLE joe LOGIN INHERIT;
CREATE ROLE admin NOINHERIT;
GRANT admin TO joe;
# joe have use of privileges granted directly to joe plus any privileges
# granted to admin, because joe "inherits" admin's privileges.

SET ROLE wheel;

GRANT UPDATE ON accounts TO joe;
REVOKE ALL ON accounts FROM PUBLIC;
GRANT ALL ON accounts TO PUBLIC;

ALTER ROLE davide WITH PASSWORD 'hu8jmn3';

CREATE USER user1 WITH PASSWORD 'secret' CREATEDB VALID UNTIL '2007-12-31';

CREATE GROUP grname WITH USER u1, u2;
ALTER GROUP grname ADD USER u3;
GRANT privilege ON object TO {PUBLIC | GROUP grame | username }
  [ WITH GRANT OPTION ] ;

### look what is:
SELECT * FROM pg_roles;
The psql program's \du meta-command is also useful for listing the existing roles.

SELECT * FROM pg_user;
SELECT * FROM pg_shadow;

# TYPE  DATABASE    USER        CIDR-ADDRESS          METHOD
# "local" is for Unix domain socket connections only
local   all         all                               trust
# user name that ident reports for the connection (typically the Unix user name)
host    postgres    all         127.0.0.1/32          ident sameuser
# IPv6 local connections:
host    all         all         ::1/128               ident sameuser
# remote connections
host    user1       all         192.168.93.0/24       md5

SELECT * FROM pg_database;
SELECT * FROM pg_tables;
SELECT * FROM pg_tables WHERE schemaname='public';
SELECT * FROM pg_namespace;
SELECT * FROM pg_tablespace;

CREATE DATABASE mydb WITH ENCODING 'UNICODE';

• www.postgresql.org
• PostgreSQL Docs.org