Obsolete Command (The GNU Troff Manual)

#### 6.1.2.5 Obsolete Command

In AT&T `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.

ddg

  Move right dd (exactly two decimal digits) basic units ‘`u`’, then print glyph g (represented as a single character).

  In GNU `troff`, arbitrary syntactical space around and within this command is allowed. Only when a preceding command on the same line ends with an argument of variable length is a separating space obligatory. In AT&T `troff`, large clusters of these and other commands are used, mostly without spaces; this made such output almost unreadable.

For modern high-resolution devices, this command does not make sense because the width of the glyphs can become much larger than two decimal digits. In `gtroff`, this is only used for the devices `X75`, `X75-12`, `X100`, and `X100-12`. For other devices, the commands ‘`t`’ and ‘`u`’ provide a better functionality.