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.
-t, -T, --terminal terminal
The following environment variable is used:
The ul command appeared in 3.0BSD.
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.
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.
The ul command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.