Terminal returns not found for most commands Mac OSX
$PATH should contain these folders: /usr/bin:/usr/sbin:/bin:/sbin.

Try editing ~/.bash_profile, ~/.profile, or ~/.bash_login (with for example /usr/bin/open ~/.bash_profile -a TextEdit) and commenting out any lines that modify the path.

If that works, you can add a line like export PATH=/opt/local/bin:/opt/local/sbin:$PATH to ~/.bash_profile.