Linux – Run netcat in background on Ubuntu Lucid 10.04

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.

I would suggest that although '&' runs the command in background, when you exit your terminal it is still getting sent SIGHUP. You could use the disown command

disown prevents the current shell from sending a HUP signal to each of the given jobs when the current shell terminates a login session.

If job is omitted, the most recently started or stopped background job is used.