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
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,
If the terminal cannot underline, underlining is ignored.
The following options are available:
Underlining is indicated by a separate line containing appropriate
this is useful when you want to look at the underlining
which is present in an
output stream on a CRT-terminal.
| -t terminal
Overrides the terminal type specified in the environment with