gtroff provides some very primitive operations for controlling
Set the page length to length (or increment or decrement the current value by length). This is the length of the physical output page. The default scaling indicator is ‘v’.
The current setting can be found in the read-only number register ‘.p’.
Note that this only specifies the size of the page, not the top and
bottom margins. Those are not set by
See Traps, for further information on how to do this.
pl values are possible also, but not very useful: No
trap is sprung, and each line is output on a single page (thus
suppressing all vertical spacing).
If no argument or an invalid argument is given,
pl sets the page
length to 11i.
gtroff provides several operations that help in setting up top
and bottom titles (or headers and footers).
Print a title line. It consists of three parts: a left justified
portion, a centered portion, and a right justified portion. The
argument separator ‘'’ can be replaced with any character not
occurring in the title line. The ‘%’ character is replaced with
the current page number. This character can be changed with the
pc request (see below).
tl is ignored.
llrequest is not honoured by
tl; use the
ltrequest (described below) instead, to control line length for text set by
tlprints the title line immediately, ignoring a partially filled line (which stays untouched).
tlaccepts the same parameter delimiting characters as the
\Aescape; see Escapes.
The title line is printed using its own line length, which is specified
(or incremented or decremented) with the
lt request. Initially,
the title line length is set to 6.5i. If a negative line length
is specified (which is not allowed),
gtroff emits a warning of
type ‘range’ and sets the title line length to zero. The default
scaling indicator is ‘m’. If
lt is called without an
argument, the title length is reset to the previous value before the
last call to
The current setting of this is available in the
number register; it is associated with the current environment
Change (increase or decrease) the page number of the next page. The only argument is the page number; the request is ignored without a parameter.
The read-only number register
.pn contains the number of the next
page: either the value set by a
pn request, or the number of the
current page plus 1.
Change the page number character (used by the
tl request) to a
different character. With no argument, this mechanism is disabled.
Note that this doesn’t affect the number register