troff output, the writing of a single glyph is
mostly done by a very strange command that combines a horizontal move
and a single character giving the glyph name. It doesn’t have a command
code, but is represented by a 3-character argument consisting of exactly
2 digits and a character.
Move right dd (exactly two decimal digits) basic units ‘u’, then print glyph g (represented as a single character).
gtroff, arbitrary syntactical space around and within this
command is allowed to be added. Only when a preceding command on the
same line ends with an argument of variable length a separating space is
obligatory. In AT&T
troff, large clusters of these and
other commands are used, mostly without spaces; this made such output
For modern high-resolution devices, this command does not make sense
because the width of the glyphs can become much larger than two decimal
gtroff, this is only used for the devices
X100-12. For other devices, the
commands ‘t’ and ‘u’ provide a better functionality.