Syntax:
set logscale <axes> <base>
set nologscale <axes>
show logscale
where <axes> may be any combinations of x, y, and z, in any order, or x2 or y2 and where <base> is the base of the log scaling. If <base> is not given, then 10 is assumed. If <axes> is not given, then all axes are assumed. set nologscale turns off log scaling for the specified axes.
Examples:
To enable log scaling in both x and z axes:
set logscale xz
To enable scaling log base 2 of the y axis:
set logscale y 2
To disable z axis log scaling:
set nologscale z