34.16. The Password File
  The file
  
   .pgpass
  
  in a user's home directory can
   contain passwords to
   be used if the connection requires a password (and no password has been
   specified otherwise). On Microsoft Windows the file is named
  
   %APPDATA%\postgresql\pgpass.conf
  
  (where
  
   %APPDATA%
  
  refers to the Application Data subdirectory in
   the user's profile).
   Alternatively, the password file to use can be specified
   using the connection parameter
  
   passfile
  
  or the environment variable
  
   PGPASSFILE
  
  .
 
This file should contain lines of the following format:
hostname:port:database:username:password
  (You can add a reminder comment to the file by copying the line above and
   preceding it with
  
   #
  
  .)
   Each of the first four fields can be a literal value, or
  
   *
  
  , which matches anything.  The password field from
   the first line that matches the current connection parameters will be
   used.  (Therefore, put more-specific entries first when you are using
   wildcards.) If an entry needs to contain
  
   :
  
  or
  
   \
  
  , escape this character with
  
   \
  
  .
   The host name field is matched to the
  
   host
  
  connection
   parameter if that is specified, otherwise to
   the
  
   hostaddr
  
  parameter if that is specified; if neither
   are given then the host name
  
   localhost
  
  is searched for.
   The host name
  
   localhost
  
  is also searched for when
   the connection is a Unix-domain socket connection and
   the
  
   host
  
  parameter
   matches
  
   libpq
  
  's default socket directory path.
   In a standby server, a database field of
  
   replication
  
  matches streaming replication connections made to the primary server.
   The database field is of limited usefulness otherwise, because users have
   the same password for all databases in the same cluster.
 
  On Unix systems, the permissions on a password file must
   disallow any access to world or group; achieve this by a command such as
  
   chmod 0600 ~/.pgpass
  
  .  If the permissions are less
   strict than this, the file will be ignored.  On Microsoft Windows, it
   is assumed that the file is stored in a directory that is secure, so
   no special permissions check is made.