ul man page
ul — do underlining
ul [options] [file...]
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.
- -i, --indicated
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, -T, --terminal terminal
Override the environment variable TERM with the specified terminal type.
- -V, --version
Display version information and exit.
- -h, --help
Display help text and exit.
The following environment variable is used:
The 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)).
colcrt(1), login(1), man(1), nroff(1), setenv(1), terminfo(5)
nroff usually outputs a series of backspaces and underlines intermixed with the text to indicate underlining. No attempt is made to optimize the backward motion.
The ul command appeared in 3.0BSD.
The ul command is part of the util-linux package and is available from Linux Kernel Archive.