Getting ready

From here on, we will assume that the psql command is enough to allow you access to the PostgreSQL server. This assumes that all your connection parameters are defaults, which may not be true.

Written in full, the connection parameters would be either of these options:

psql -h myhost -p 5432 -d mydb -U myuser 
psql postgresql://myuser@myhost:5432/mydb

The default value for the port (-p) is 5432. By default, mydb and myuser are both identical to the operating system's username. The default myhost on Windows is localhost, while on Unix, we use the default directory for Unix socket connections. The location of such directories varies across distributions and is set at compile time. However, note that you don't actually need to know its value, because on local connections both the server and the client are normally compiled together, so they use the same default.