2.3 Incrementing and decrementing numeric variables

The increment command and decrement commands can be used to increment or decrement a numeric variable by 1.

The syntax is

increment <variable>; decrement <variable>;

Some examples are

setvar ~my_num, 4; increment ~my_num; #value of ~my_num is now 5 decrement ~my_num; #value of ~my_num is now 4