I can't seem to open patches from the terminal in OS X (with pd-extended, the second command works with vanilla).  I try either:

/Applications/Pd-extended.app/Contents/Resources/bin/pd ~/pd/externals/incr/incr-help.pd
/Applications/Pd-extended.app/Contents/Resources/bin/pd -open ~/pd/externals/incr/incr-help.pd

without success.