ul [-i] [-t terminal] [name …]
Ul reads the named files (or standard input if none are given) and translates occurrences of underscores to the sequence that indicates underlining for the terminal in use, as specified by the environment variable TERM . The file /etc/termcap 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, ul degenerates to cat(1). If the terminal cannot underline, underlining is ignored.
The following options are available:
–i 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 nroff output stream on a CRT terminal.
-t terminal Overrides the terminal type specified in the environment with terminal.