see also :
colcrt - man - nroff
add an example, a script, a trick and tips
The ul 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 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.
During the translation some other special characters also
get translated. E.g. TAB gets expanded to spaces.
options are available:
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(1) output
stream on a CRT-terminal.
Overrides the terminal type
specified in the environment with terminal.
The LANG, LC_ALL, LC_CTYPE and TERM environment variables affect
the execution of ul as described in environ(7).
The ul utility exits 0 on success, and >0 if
an error occurs.
The nroff(1) 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.
August 4, 2004 BSD
The ul command appeared
colcrt , man , nroff