This chapter outlines the interaction between Postgres and the operating system.
All Postgres commands that are executed directly from a Unix shell are found in the directory .../bin. Including this directory in your search path will make executing the commands easier.
A collection of system catalogs exist at each site. These include a class (pg_user) that contains an instance for each valid Postgres user. The instance specifies a set of Postgres privileges, such as the ability to act as Postgres super-user, the ability to create/destroy databases, and the ability to update the system catalogs. A Unix user cannot do anything with Postgres until an appropriate instance is installed in this class. Further information on the system catalogs is available by running queries on the appropriate classes.