SysIII/usr/games/lib/backrules

To play backgammon, you must type the numbers
of the points from which pieces are to be
moved. For example, if the roll was '2  6',
typing '12 15' will move a piece from point
12 two spaces to point 14 and a piece from
point 15 six spaces to point 21. If the moves
must be made in the opposite order, you must
prepend the first number with a minus ('-').
Thus, typing '-12 15' will move a piece from
point 12 six spaces and a piece from point 15
two spaces. If you want to move a single piece
several times the sequence of points from
which it is to be moved must be typed. For 
example, if the roll is '3  5', typing
'14  17' will move a piece from point 14 to
point 17 and then to point 22. If a double
is rolled, you should enter four numbers.

Brown pieces that have been removed from the
board after being hit by white are on point 0
and must be brought in before any other moves
can be made. White pieces that are hit are 
removed to point 25.

Illegal or excessive moves are detected, however
if you choose to skip part or all of your turn
you may do so. Type a '?' when you are asked
for your move and a list of available actions 
will be printed. Good luck!!!