Continuing my notes publishing ... How to backup/restore your PostgreSQL databases? when you recently get the responsibility of a web app? or you will renew your development environment? or you want to reproduce a production error in your machine? or you want to sleep better at night ;-) ? or ....? whatever. Before to do anything always we should log as postgres user:

sudo su - postgres

Then backup one database:

pg_dump database_name > /tmp/database_name.bak

Or backup them all:

pg_dumpall > /tmp/backup_all.bak

After that you probably want to download them from server to your machine:

scp your.server.com:/tmp/backup_all.bak .

And finally you want to restore one database, but you will need to create the database previously:

createdb -T template0 database_name
psql database_name < database_name.bak

Maybe you also need to create a user and give it proper permissions:

psql
create role user_name with createdb login password 'user_password';

Or restore them all:

psql -f backup_all.bak postgres

This will create all databases and users for you.