This sets autoscaling of the y axis (other axes are not affected):
set autoscale y
This sets autoscaling only for the minimum of the y axis (the maximum of the y axis and the other axes are not affected):
set autoscale ymin
This disables extension of the x2 axis tics to the next tic mark, thus keeping the exact range as found in the plotted data and functions:
set autoscale x2fixmin set autoscale x2fixmax
This sets autoscaling of the x and y axes:
set autoscale xy
This sets autoscaling of the x, y, z, x2 and y2 axes:
set autoscale
This disables autoscaling of the x, y, z, x2 and y2 axes:
unset autoscale
This disables autoscaling of the z axis only:
unset autoscale z