Space downwards distance. With no argument it advances
1 line. A negative argument causes
gtroff to move up the
page the specified distance. If the argument is preceded by a ‘|’
gtroff moves that distance from the top of the page. This
request causes a line break, and that adds the current line spacing to
the space you have just specified. The default scaling indicator is
For convenience you may wish to use the following macros to set the height of the next line at a given distance from the top or the bottom of the page:
.de y-from-top-down . sp |\\$1-\\n[.v]u .. . .de y-from-bot-up . sp |\\n[.p]u-\\$1-\\n[.v]u ..
A call to ‘.y-from-bot-up 10c’ means that the bottom of the next line will be at 10cm from the paper edge at the bottom.
If a vertical trap is sprung during execution of
sp, the amount
of vertical space after the trap is discarded. For example, this
.de xxx .. . .wh 0 xxx . .pl 5v foo .sp 2 bar .sp 50 baz
foo bar baz
The amount of discarded space is available in the number register
sp against vertical traps, use the
.vpt 0 .sp -3 .vpt 1
Output nnn-1 blank lines after each line of text. With
gtroff uses the previous value before the last
.ls 2 \" This causes double-spaced output .ls 3 \" This causes triple-spaced output .ls \" Again double-spaced
The line spacing is associated with the current environment (see Environments).
The read-only number register
.L contains the current line
See Changing Type Sizes, for the requests
Sometimes, extra vertical spacing is only needed occasionally, e.g. to
allow space for a tall construct (like an equation). The
escape does this. The escape is given a numerical argument, usually
enclosed in quotes (like ‘\x'3p'’); the default scaling indicator
is ‘v’. If this number is positive extra vertical space is
inserted below the current line. A negative number adds space above.
If this escape is used multiple times on the same line, the maximum of
the values is used.
See Escapes, for details on parameter delimiting characters.
.a read-only number register contains the most recent
(nonnegative) extra vertical line space.
\x can be necessary in combination with the
escape, as the following example shows.
This is a test with the \[rs]b escape. .br This is a test with the \[rs]b escape. .br This is a test with \b'xyz'\x'-1m'\x'1m'. .br This is a test with the \[rs]b escape. .br This is a test with the \[rs]b escape.
This is a test with the \b escape. This is a test with the \b escape. x This is a test with y. z This is a test with the \b escape. This is a test with the \b escape.
Enable no-space mode. In this mode, spacing (either via
or via blank lines) is disabled. The
bp request to advance to
the next page is also disabled, except if it is accompanied by a page
number (see Page Control, for more information). This mode ends
when actual text is output or the
rs request is encountered, which
ends no-space mode. The read-only number register
.ns is set
to 1 as long as no-space mode is active.
This request is useful for macros that conditionally insert vertical space before the text starts (for example, a paragraph macro could insert some space except when it is the first paragraph after a section header).