Emacs Power Usage
Selecting modes, minor modes
Emacs will normally select modes correctly automaticly according to file name,
or buffer contents. But we may want to change modes ourselves,
this is most easily accomplished by M-x .
Different Emacs modes create different key strokes to behave differently
even though most keys will remain the same.
Minor modes are optional features which you can turn on or off.
All the minor modes are independent of each other.
minor modes apply to buffers, but some are designed to work on
all buffers, and are activated or deactivated according to a global
variable(one can change this by making the variable local for
one or more buffers)