ul — do underlining
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 which
indicates underlining for the terminal in use, as specified
by the environment variable TERM. The terminfo database 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:
−iUnderlining 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 terminalOverrides the terminal type specified in the
environment with terminal.
The following environment variable is used:
TERMThe TERM variable is
used to relate a tty device with its device capability
description (see terminfo(5)).
TERM is set at login
time, either by the default terminal type specified in
/etc/ttys or as set
during the login process by the user in their
login
file (see setenv(1)).