5.20.2 Changing the Vertical Spacing

Request: .vs [space]

Request: .vs +space

Request: .vs -space

Register: \n[.v]

Set the vertical spacing to, or alter it by, space. The default scaling unit is ‘p’. If vs is called without an argument, the vertical spacing is reset to the previous value before the last call to vs. GNU troff emits a warning in category ‘range’ if space is negative; the vertical spacing is then set to the smallest possible positive value, the vertical motion quantum (as found in the .V register).

‘.vs 0’ isn’t saved in a diversion since it doesn’t result in a vertical motion. You must explicitly issue this request before interpolating the diversion.

The read-only register .v contains the vertical spacing; it is associated with the environment (see Environments).

When a break occurs, GNU troff performs the following procedure.

• Move the drawing position vertically by the extra pre-vertical line space, the minimum of all negative \x escape sequence arguments in the pending output line.
• Move the drawing position vertically by the vertical line spacing.
• Write out the pending output line.
• Move the drawing position vertically by the extra post-vertical line space, the maximum of all positive \x escape sequence arguments in the line that has just been output.
• Move the drawing position vertically by the post-vertical line spacing (see below).

Prefer vs or pvs over ls to produce double-spaced documents. vs and pvs have finer granularity than ls; moreover, some preprocessors assume single spacing. See Manipulating Spacing, regarding the \x escape sequence and the ls request.

Request: .pvs [space]

Request: .pvs +space

Request: .pvs -space

Register: \n[.pvs]

Set the post-vertical spacing to, or alter it by, space. The default scaling unit is ‘p’. If pvs is called without an argument, the post-vertical spacing is reset to the previous value before the last call to pvs. GNU troff emits a warning in category ‘range’ if space is negative; the post-vertical spacing is then set to zero.

The read-only register .pvs contains the post-vertical spacing; it is associated with the environment (see Environments).