The
utility reads the named files (or standard input if none are given) and translates occurrences of underscores to the sequence which indicates underlining for the terminal in use, as specified by the environment variable
The file
is read to determine the appropriate sequences for underlining. If the terminal is incapable of underlining, but is capable of a standout mode then that is used instead. If the terminal can overstrike, or handles underlining automatically,
degenerates to
If the terminal cannot underline, underlining is ignored. During the translation some other special characters also get translated. E.g. TAB gets expanded to spaces.
The following options are available:
Underlining is indicated by a separate line containing appropriate dashes
this is useful when you want to look at the underlining which is present in an
output stream on a CRT-terminal.
Overrides the terminal type specified in the environment with
The
and
environment variables affect the execution of
as described in
The
command appeared in
The
command usually outputs a series of backspaces and underlines intermixed with the text to indicate underlining. No attempt is made to optimize the backward motion.