grep-scroll-output

grep-scroll-output is a variable defined in `grep.el'.
Its value is

nil

Documentation:
Non-nil to scroll the *grep* buffer window as output appears.

Setting it causes the grep commands to put point at the end of their
output window so that the end of the output is always visible rather
than the beginning.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.