How do I copy the content of a whole disk on OSX 10.3
cp -a is just a shortcut for cp -pPR, these options are available in the 10.3 version of cp already. So you can copy the content of your disk with

cp -pPR /old/path /Volumes/new/path


You can also avoid using Terminal altogether and just drag the top folder you want to keep onto the external drive in Finder.