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.\"     @(#)ul.1	8.1 (Berkeley) 6/6/93
.\" $FreeBSD: head/usr.bin/ul/ul.1 299288 2016-05-09 20:55:35Z bapt $
.\"
.Dd August 4, 2004
.Dt UL 1
.Os
.Sh NAME
.Nm ul
.Nd do underlining
.Sh SYNOPSIS
.Nm
.Op Fl i
.Op Fl t Ar terminal
.Op Ar
.Sh DESCRIPTION
The
.Nm
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
.Ev TERM .
The file
.Pa /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,
.Nm
degenerates to
.Xr 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.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl i
Underlining is indicated by a separate line containing appropriate
dashes
.Ql \- ;
this is useful when you want to look at the underlining
which is present in an
.Xr nroff 1
output stream on a CRT-terminal.
.It Fl t Ar terminal
Overrides the terminal type specified in the environment with
.Ar terminal .
.El
.Sh ENVIRONMENT
The
.Ev LANG , LC_ALL , LC_CTYPE
and
.Ev TERM
environment variables affect the execution of
.Nm
as described in
.Xr environ 7 .
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr colcrt 1 ,
.Xr man 1 ,
.Xr nroff 1
.Sh HISTORY
The
.Nm
command appeared in
.Bx 3.0 .
.Sh BUGS
The
.Xr 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.