Nigel Henry wrote:
You say above, and I tried "su -", and found myself in roots home directory with no access to the "SConstruct" file in my /home/user directory.
How do I change back to my source directory after I've done a "su -" ?
Use cd. Something like "cd /home/user/path/to/dir/with/SConstruct".
(You can use the shortcut ~user in place of /home/user similarly to how you can use ~ to point to your own home directory.)