.\" This module is believed to contain source code proprietary to AT&T.
.\" Use and redistribution is subject to the Berkeley Software License
.\" Agreement and your Software Agreement with AT&T (Western Electric).
.\"
.\"	@(#)tt05	8.1 (Berkeley) 6/8/93
.\" Copyright (C) Caldera International Inc. 2001-2002.  All rights reserved.
.\" 
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions are
.\" met:
.\" 
.\" Redistributions of source code and documentation must retain the above
.\" copyright notice, this list of conditions and the following
.\" disclaimer.
.\" 
.\" Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 
.\" All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" 
.\" This product includes software developed or owned by Caldera
.\" International, Inc.  Neither the name of Caldera International, Inc.
.\" nor the names of other contributors may be used to endorse or promote
.\" products derived from this software without specific prior written
.\" permission.
.\" 
.\" USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
.\" INTERNATIONAL, INC.  AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
.\" DISCLAIMED.  IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE
.\" FOR ANY DIRECT, INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
.\" OR OTHERWISE) RISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
.\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" 
.\" $FreeBSD$
.\"
.NH
Tabs
.PP
Tabs
(the \s8ASCII\s0 `horizontal tab' character)
can be used to produce output in columns,
or to set the horizontal position of output.
Typically
tabs are used only in unfilled text.
Tab stops are set by default every half inch from the
current indent,
but
can be changed by the
.BD .ta
command.
To set stops every inch, for example,
.P1
^ta 1i 2i 3i 4i 5i 6i
.P2
.PP
Unfortunately the stops are left-justified only
(as on a typewriter),
so lining up columns of right-justified numbers can be painful.
If you have many numbers,
or if you need more complicated table layout,
.ul
don't
use
.UL troff 
directly;
use the
.UL tbl
program described in [3].
.PP
For a handful of numeric columns, you can do it this way:
Precede every number by enough blanks to make it line up
when typed.
.P1
^nf
^ta 1i 2i 3i
\0\01\0\fItab\fR\0\0\02\0\fItab\fR\0\0\03
\040\0\fItab\fR\0\050\0\fItab\fR\0\060
700\0\fItab\fR\0800\0\fItab\fR\0900
^fi
.P2
Then change each leading blank into the string
.BD \e0 .
This is a character that does not print, but that has
the same width as a digit.
When printed, this will produce
.P1
.ta 1i 2i 3i
\0\01	\0\02	\0\03
\040	\050	\060
700	800	900
.P2
.PP
It is also possible to fill up tabbed-over space with
some character other than blanks by setting the `tab replacement character'
with the
.BD .tc
command:
.P1
^ta 1.5i 2.5i
^tc \e(ru	(\e(ru is "\(ru")
Name \fItab\fR Age \fItab\fR 
.P2
produces
.P1 3
.ta 1.5i 2.5i
.tc \(ru
Name	 Age 	
.tc
.P2
To reset the tab replacement character to a blank, use
.BD .tc
with no argument.
(Lines can also be drawn with the
.BD \el
command, described in Section 6.)
.PP
.UL troff
also provides a very general mechanism called `fields'
for setting up complicated columns.
(This is used by
.UL tbl ).
We will not go into it in this paper.