Upgraded 10.6 from 10.5 and now postgres 8.1 is whacked. To make things worse I tried installing 8.4 which I\'m pretty sure just made things ten times worse. Anyhow, the e
I can add this tiny command to the answer too:
rm /usr/bin/psql
Remove executable psql alias.
The problem was with the PostgreSQL account sitting on my machine.
I removed the account and proceeded with the uninstall using the instructions here:
In the installation directory, there will be a uninstall-postgresql.app file. Executing (double clicking) that will uninstall the PostgreSQL installation.
Stop the server:
sudo /sbin/SystemStarter stop postgresql-8.3
Remove menu shortcuts:
sudo rm -rf /Applications/PostgreSQL 8.3
Remove the ini file:
sudo rm -rf /etc/postgres-reg.ini
Removing Startup Items:
sudo rm -rf /Library/StartupItems/postgresql-8.3
Remove the data and installed files:
sudo rm -rf /Library/PostgreSQL/8.3
Delete the user postgres:
sudo dscl . delete /users/postgres
If you have newer Postgres and/or OSX/macOS version, you can check this answer.