Postgresql – What package do install to get access to “psql” client on windows

The directory /usr/local/pgsql/bin is not in your PATH (and neither is . - which is a good thing for security reasons). Simply run it like this if you're in that directory:

./psql test

which says run psql from the current directory (./).

Assuming Ubuntu does the same thing as Debian, then your two PostGreSQL instances will be running on different ports.

You can easily check the config files to see which version is on which port:

$ grep -H '^port' /etc/postgresql/*/main/postgresql.conf
/etc/postgresql/8.4/main/postgresql.conf:port = 5432
/etc/postgresql/8.3/main/postgresql.conf:port = 5433

Most of the PostGreSQL commands take the "-p ####" or "--port=####" option, so you can use that to select the version you want.