More Permissions and URL information:

in browser: type: https://www.cs.umb.edu/cs410
   see our first cs410 class project using symlinks

You have to know that Tom M set this URL to point to:
   /courses/cs410/f26/hdeblois/software

The default websites use URL https://www.cs.umb.edu/~<csuname>
   to point to /home/<csuname>/cs410/public_html/index.html

What displays?  If there is an index.html, it renders.
  If there is no index.html in the directory, then an index is displayed.
  SO you can nest additional website versions below a particlular website you built.

STICKY bit 's' - use to restrict deletion and renaming in a shared directory so it can only be done   by owner or root.
  chmod +t /path-to-dir or
  using full rwx as 777, do chmod 1777 /path-to-dir

umask: type umask, then man umask - says permissions NOT to give out!
  umask - displays it
  umask 0022 - resets it
  In Linux, umask (User Mask) is a built-in shell command and system call that determines 
  the default file and directory creation permissions by not allowing the ones it has
  It's a security filter. 
  It subtracts or clears specific permission bits from the system's maximum default permissions.
  New files start out allowing everything to everyone.
  *** umask does a bitwise AND with the bitwise complement of the umask ***