Блог @ Ihtiandr.Info

Step 1. Edit PostgreSQL config file to establish trust relationship to login without password:
# vi /var/lib/pgsql/data/pg_hba.conf
Old Line:
local all postgres password
Change it to:
local all postgres trust

Step 2. Restart PostgreSQL Server:
# service postgresql restart

Step 3. Change password:
# psql -U postgres template1 -c alter user postgres with password ‘newpassword’;

Step 4. Password has been updated. Revert back the original settings of config file:
# vi /var/lib/pgsql/data/pg_hba.conf
Old Line:
local all postgres trust
Change it to:
local all postgres password

Step 5. Restart server and use your new password to access PostgreSQL Server.
# service postgresql restart