R: 4 W: 2 X: 1
Make a directory readable to other people.
chmod 755 dir
Make a file readable to other people.
chmod 644 file
Make a directory and all its subcontents readable to other people.
# make the dir and its subcontents readable and executable
chmod 755 -R dir
# remove executable permission from files
find dir -type f | xargs chmod -x