set [m]x[<axisnumber>]tics [axis|border|inward|outward|both] [auto | [<minimum>,] <increment[, <maximum>] | ( '<label>' <position> ... ) ]
The xtics option specifies the positions of tick marks on the -axis (similarly, ytics acts on the
-axis). One can specify:
The axis to modify; if none is specified, then the command acts upon all axes.
mxtics to alter the placement of minor tic marks.
The keywords inward, outward and both, which alter the directions of the tics. axis is an alias for inward, border for outward.
The autofreq keyword restores automatic placement of the tics
If minimum, increment, maximum are specified, then ticks are placed at evenly spaced intervals between the specified limits. In the case of logarithmic axes, increment is applied multiplicatively.
The final form allows ticks to be placed on an axis manually with individual labels.
Two examples:
set xtics 2 1 5
will set tick marks on the -axis at positions 2, 3, 4 and 5.
set x2tics ("a" 2, "b" 3)
will set tick marks on the second -axis at positions 2 and 3 reading ‘a’ and ‘b’ respectively.