The TAB ADJUST (abbreviated TA A) command shifts each of a range of
lines a specified number of logical tab stops.

Format: TAB ADJUST [-] n [range]

where n is the number of tab stops to shift.  You must use the SET TAB
command to set the logical tab size in order for this command  to work.
If you omit range, the select range is assumed.  If a minus sign (-)
precedes the count n, the text shifts to the left.  Otherwise, it shifts
to the right.