.pgpass is a common way to store connection information in PostgreSQL instead of typing password every time your login to your database using psql.

On Windows, the file is named %APPDATA%\postgresql\pgpass.conf.

You can create a .pgpass file in your home folder and input your login credentials with the following structure:

host:port:db_name:user_name:password

Example:

localhost:5432:postgres:myadmin:Str0ngP@ssw0rd

Except for the password, each field can be replaced with an asterisk ( *) value to match anything.

Example:

*:*:*:postgres:myadmin:Str0ngP@ssw0rd

It means you can use the username myadmin and password Str0ngP@ssw0rd to login to the database postgres on every host and port.

After you finish, remember to set the proper permission so it would be used by psql:
sudo chmod 600 .pgpass

Export the PGPASSFILE file to set environment variable:

export PGPASSFILE='/home/user/.pgpass'

参考

How to use .pgpass in PostgreSQL?