PWB1/usr/man/man1/tabs.1

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.th TABS I 5/31/77
.sh NAME
tabs \*- set tabs on terminal
.sh SYNOPSIS
.bd tabs
[tabspec]
[\fB+f\fR]
[\fB+m\fRn]
[\fB+l\fRn]
[\fB+t\fRtype]
[\fB+q\fR]
.sh DESCRIPTION
.it Tabs
sets the tab stops on the user's terminal according to the tab specification
\fItabspec\fR,
after clearing any previous settings.
The user must of course be logged in on a terminal
with remotely-settable
hardware tabs,
including the DASI450 (DIABLO 1620 or XEROX 1700),
GSI300 (DTC300 or DASI300),
DASI300S (DTC300S),
HP2640B (HP2640A, HP2644A, HP2645A, etc.),
.if t \s-2TELETYPE\s+2\(rg
.if n TELETYPE(Rg.)
Model 40/2,
and General Electric TermiNet terminals.
.s1
Users of TermiNet terminals should be aware that they
behave in a different way than most other terminals for some tab settings;
the first number in a list of tab settings becomes the
.it "left margin"
on
a TermiNet terminal.
Thus, any list of tab numbers whose first element is other than 1 causes a
margin to be left by a TermiNet, but not by other terminals.
A tab list beginning with 1 causes the same
effect regardless of terminal type.
It is also possible to set a left margin on the
DASI450 and DASI300S,
although in a different way.
.s1
Four types of tab specification are accepted for
.it tabspec:
`canned', repetitive,
arbitrary, and file.
If no arguments are given, the default value is \fB\*-8\fR, i.e.,
UNIX `standard' tabs.
The lowest column number is 1 and the highest is 158.
Note that for
.it tabs,
column 1 always refers to the leftmost column on a terminal,
even one whose column markers
begin at 0,
e.g., the DASI300, DASI300S, and DASI450.
.s1
.lp +8 7
\fB\*-\fIcode\fR	Gives the name of one of a set of `canned' tabs.
The legal codes and their meanings are as follows:
.s1
.lp +8 7
\fB\*-a\fR	1,10,16,36,72
.br
Assembler, IBM S/370, first format
.s1
.lp +8 7
\fB\*-a2\fR	1,10,16,40,72
.br
Assembler, IBM S/370, second format
.s1
.lp +8 7
\fB\*-c\fR	1,8,12,16,20,55
.br
COBOL, normal format
.s1
.lp +8 7
\fB\*-c2\fR	1,6,10,14,49
.br
COBOL compact format (columns 1\*-6 omitted).
Using this code, the first typed character corresponds to card column 7,
one space gets you to column 8, and a tab reaches column 12.
In order to get
.it "send(I)"
to prepend the blanks at the beginning, files using this tab setup
should include a format specification (see
.it "fspec\^\c"
(V)) as follows:
.br
\fB<:t\*-c2 m6 s66 d:>\fR
.s1
.lp +8 7
\fB\*-c3\fR	1,6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,67
.br
COBOL compact format (columns 1\*-6 omitted), with more tabs than
.bd \*-c2.
THIS IS THE RECOMMENDED FORMAT FOR COBOL.
The appropriate format specification is:
.br
\fB<:t\*-c3 m6 s66 d:>\fR
.s1
.lp +8 7
\fB\*-f\fR	1,7,11,15,19,23
.br
FORTRAN
.s1
.lp +8 7
\fB\*-p\fR	1,5,9,13,17,21,25,29,33,37,41,45,49,53,57,61
.br
PL/I
.s1
.lp +8 7
\fB\*-s\fR	1,10,55
.br
SNOBOL
.s1
.lp +8 7
\fB\*-u\fR	1,12,20,44
.br
UNIVAC 1100 Assembler
.s2
.i0
In addition to these `canned' formats, three other types exist:
.s1
.lp +8 7
\fB\*-\fIn\fR	A repetitive specification requests tabs at columns 1+\fIn\fR,
1+2*\fIn\fR, etc.
Note that such a setting leaves a left margin of \fIn\fR columns on TermiNet
terminals
.it only.
Of particular importance is the value \fB\*-8\fR: this represents the
UNIX `standard' tab setting, and is the most likely tab setting to be found
at a terminal.
It is required for use with the
.it nroff\^\c
(I)
.bd \*-h
option for high-speed output (about 10% speed increase).
Another special case is the value \fB\*-0\fR, implying no tabs at all.
.s3
.lp +8 7
\fIn1,n2,...\fR	 The arbitrary format permits the user to type any
chosen set of numbers, separated by commas, in ascending order.
Up to 40 numbers are allowed.
The maximum tab value accepted is 158.
If any number (except the first one) is preceded by a plus sign, it is taken
as an increment to be added to the previous value.
Thus, the tab lists 1,10,20,30 and 1,10,+10,+10 are considered identical.
.s3
.lp +8 7
\fB\*-\*-\fIfile\fR	 If the name of a file is given,
.it tabs
reads the first line of the file, searching for a format specification
(see
.it "fspec(V)\c"
).
If it finds one there, it sets the tab stops according to it, otherwise it
sets them as \fB\*-8\fR.
If an actual format specification is found in the file, it is printed at the
terminal to remind the user what it is, unless the
.bd +f
flag is also
included to suppress this output.
This type of specification may be used to make sure that a tabbed file is printed
with correct tab settings, and would be used with the
.it pr(I)
command:
.s1
\fBtabs\fR \*-\*-file; \fBpr\fR file
.s2
.i0
Any of the following may be used also;
if a given flag occurs more than once,
the last value given takes effect.
.s2
.lp +8 7
\fB+f\fR	If the \*-\*-\c
.it file
type of tab specification is used and
this option given, no tab specification is printed at the terminal,
but the tab stops are set.
This option is most useful when 
.it tabs
is invoked from a shell procedure or another command, rather than directly
from a terminal.
This option has no effect unless a \*-\*-\fIfile\fR form of specification
is used.
.s2
.lp +8 7
\fB+l\fIn\fR	The length argument gives the number of the rightmost column at
which a tab will be set by a repetitive\*-style specification.
The default value is 132,
but may be different if the
.bd +t
argument implies a more appropriate value for the specific type of terminal being used.
When examining printed output obtained from another computer,
it is helpful to have tabs across the entire width of the terminal.
Maximum usable values of \fIn\fR are 118 (TermiNet),
132 (any DASI in 10-pitch mode),
158 (any DASI in 12-pitch mode),
and 80 (HP2640).
Although
.it tabs
will accept larger values without diagnostics, using them may cause a terminal
(especially a DASI) to behave strangely.
.s2
.lp +8 7
\fB+m\fIn\fR	The margin argument may be used for TermiNet,
DASI450, and DASI300S terminals.
It causes
all tabs to be moved over
.it n
columns by making column
.it n+1
the left margin.
If
.bd +m
is given without a value of
.it n,
the value assumed is 10.
For a TermiNet, the first value in the tab list should
be 1,
or the margin will move even further to the right.
.s1
To reset the left margin of a DASI450 to the normal(leftmost) position, type:
.s1
\fBtabs +t450 +m0\fR
.s1
The margin on a DASI450 or DASI300S is reset only when the
.bd +m
flag is given explicitly.
The margin is not settable on a DASI300,
and is settable on the DASI450 and DASI300S
.it only
when the
.bd +t
option is used (see below).
.s2
.lp +8 7
\fB+q\fR	The
(`quick') flag suppresses the emission of characters to clear
previously set tabs.
It can be used if the terminal is know to be clear
already, i.e., just after it has been powered up or reset.
.s2
.lp +8 7
\fB+t\fItype\fR	The terminal type can be supplied to help
.it tabs
optimize its output for specific kinds of terminals,
and is sometimes required when certain functions of some terminals are desired.
This argument interacts with
.bd +l
by setting different defaults for different terminals,
and different maximum lengths.
It interacts with
.bd +m
because different methods must be used to set margins
on the various terminals.
.s1
Given below are the possible cases for
.bd +t
argument,
listing argument value, maximum length,
default length if \fB+l\fR is omitted, and notes.
The notes give the following codes:
\&`S' for a short (several characters) clearing sequence,
\&`L' for a long sequence (about 60 characters),
\&`M' for a settable margin,
and a list of the terminal types expected.
.s2
.i0
.if n .ta 9 18 26 31 35
.if t .ta .8i 1.7i 2.5i 3.0i 3.5i
.nf
.if n .ul
\fBValue	Maximum	Default	S/L	M	Terminal(s)\fR
\fB+t300\fR	158	132	L		GSI300 (DTC300 or DASI300)
\fB+tgsi\fR	"	"	"		"
\fB+t300S\fR	158	132	S	M	DASI300S (DTC300S)
\fB+tgsis\fR	"	"	"	"	"
\fB+t450\fR	158	132	S	M	DASI450 (DIABLO 1620 or XEROX 1700)
\fB+t1620\fR	"	"	"	"	"
\fB+ttn\fR	118	118	S	M	TermiNet 300 or 1200
\fB+thp\fR	80	80	L		HP2640A, HP2640B
\fB+t40\*-2\fR	80	80	S		TELETYPE 40/2
\fB+t\fR	158	132	S		any with settable tabs
omitted	158	132	L		any with settable tabs
.fi
.s3
.lp +8 7
\&	Omitting the
.bd +t
argument entirely will work for most situations.
You should probably try to type the least that will work,
and be more specific only when necessary.
.i0
.s2
Tab-setting is performed using the standard output.
.sh DIAGNOSTICS
"illegal tabs" when arbitrary tabs are ordered incorrectly, or include
any value greater than 158.
.br
"illegal increment" when a zero or missing increment value is found in
an arbitrary specification.
.br
"unknown tab code" when a `canned' code cannot be found.
.br
.br
"can't open" if \*-\*-file option used, and file can't be opened.
.br
"file indirection" if \*-\*-file option used and the specification
in that file points to yet another file.
Indirection of this form is not permitted.
.br
.ne 5
.sh "EXIT CODES"
0 \*- normal
.br
1 \*- for any error
.sh "SEE ALSO"
fspec(V), nroff(I), reform(I), send(I)
.br
GSI300(VII), DASI450(VII), HP2640(VII), TERMINET(VII)
.sh BUGS
It is sad, but true,
that it is often necessary to specify the terminal type.
Various terminals use totally inconsistent ways of clearing tabs and
setting margins.
.it Tabs
clears only 20 tabs (on terminals requiring a long sequence),
but is willing to set 40.