dropdb — remove a PostgreSQL database
dropdb [connection-option...] [option...]  dbname 
dropdb destroys an existing PostgreSQL database. The user who executes this command must be a database superuser or the owner of the database.
dropdb is a wrapper around the SQL command DROP DATABASE. There is no effective difference between dropping databases via this utility and via other methods for accessing the server.
dropdb accepts the following command-line arguments:
dbnameSpecifies the name of the database to be removed.
-e--echoEcho the commands that dropdb generates and sends to the server.
-i--interactiveIssues a verification prompt before doing anything destructive.
-V--versionPrint the dropdb version and exit.
--if-existsDo not throw an error if the database does not exist. A notice is issued in this case.
-?--helpShow help about dropdb command line arguments, and exit.
dropdb also accepts the following command-line arguments for connection parameters:
-h host--host=hostSpecifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix domain socket.
-p port--port=portSpecifies the TCP port or local Unix domain socket file extension on which the server is listening for connections.
-U username--username=usernameUser name to connect as.
-w--no-password
        Never issue a password prompt.  If the server requires
        password authentication and a password is not available by
        other means such as a .pgpass file, the
        connection attempt will fail.  This option can be useful in
        batch jobs and scripts where no user is present to enter a
        password.
       
-W--passwordForce dropdb to prompt for a password before connecting to a database.
        This option is never essential, since
        dropdb will automatically prompt
        for a password if the server demands password authentication.
        However, dropdb will waste a
        connection attempt finding out that the server wants a password.
        In some cases it is worth typing -W to avoid the extra
        connection attempt.
       
--maintenance-db=dbname
         Specifies the name of the database to connect to in order to drop the
         target database. If not specified, the postgres
         database will be used; if that does not exist (or is the database
         being dropped), template1 will be used.
       
PGHOSTPGPORTPGUSERDefault connection parameters
PG_COLOR
      Specifies whether to use color in diagnostic messages. Possible values
      are always, auto and
      never.
     
This utility, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see Section 33.14).
In case of difficulty, see DROP DATABASE and psql for discussions of potential problems and error messages. The database server must be running at the targeted host. Also, any default connection settings and environment variables used by the libpq front-end library will apply.
    To destroy the database demo on the default
    database server:
$dropdb demo
    To destroy the database demo using the
    server on host eden, port 5000, with verification and a peek
    at the underlying command:
$dropdb -p 5000 -h eden -i -e demoDatabase "demo" will be permanently deleted. Are you sure? (y/n)yDROP DATABASE demo;