How can I connect to a PostgreSQL database using the command line?
Use psql.
On localhost you can login with:
$ psql -U <username> -W <password> <database name>
In default settings, your username is postgres and you can leave the password blank
$ psql -U postgres <database name>
#Making a remote connection
$ psql -U <username> -W <password> -p <port> -h <host> <database name>
If you have a connection string you can also simply pass in the connection string to psql
$ psql postgresql://user@hostname:5433/database_name?sslmode=require
The above command will prompt for a password (or pass in -w for no password)