TABS(C) UNIX System V
Name
tabs - set tabs on a terminal
Syntax
tabs [tabspec] [-Ttype] [+mn]
Description
The tabs command sets the tab stops on the user's terminal
according to the tab specification tabspec, after clearing
any previous settings. The user's terminal must have
remotely-settable hardware tabs.
tabspec Four types of tab specification are accepted for
tabspec. They are described below: canned (-code),
repetitive (-n), arbitrary (n1,n2,...), and file
(--file). If no tabspec is given, the default value
is -8, i.e., ``standard'' UNIX tabs. The lowest
column number is 1. Note that for tabs, column 1
always refers to the leftmost column on a terminal,
even one whose column markers begin at 0, e.g., the
DASI 300, DASI 300s, and DASI 450.
-code Use one of the codes listed below to select a canned
set of tabs. The legal codes and their meanings are
as follows:
-a 1,10,16,36,72
Assembler, IBM S/370, first format
-a2 1,10,16,40,72
Assembler, IBM S/370, second format
-c 1,8,12,16,20,55
COBOL, normal format
-c2 1,6,10,14,49
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. Files using this tab setup should
include a format specification as follows
[see fspec(F)]:
<:t-c2 m6 s66 d:>
-c3 1,6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,67
COBOL compact format (columns 1-6 omitted),
with more tabs than -c2. This is the
recommended format for COBOL. The
appropriate format specification is [see
fspec(F)]:
<:t-c3 m6 s66 d:>
-f 1,7,11,15,19,23
FORTRAN
-p 1,5,9,13,17,21,25,29,33,37,41,45,49,53,57,61
PL/I
-s 1,10,55
SNOBOL
-u 1,12,20,44
UNIVAC 1100 Assembler
-n A repetitive specification requests tabs at columns
1+n, 1+2*n, etc. Of particular importance is the
value 8: this represents the ``standard'' UNIX tab
setting, and is the most likely tab setting to be
found at a terminal. Another special case is the
value 0, implying no tabs at all.
n1,n2,...
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. 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 formats
1,10,20,30, and 1,10,+10,+10 are considered
identical.
--file If the name of a file is given, tabs reads the first
line of the file, searching for a format
specification [see fspec(F)]. If it finds one
there, it sets the tab stops according to it,
otherwise it sets them as -8. 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 pr(C) command:
tabs -- file; pr file
Any of the following also may be used; if a given flag
occurs more than once, the last value given takes effect:
-Ttype tabs usually needs to know the type of terminal in
order to set tabs and always needs to know the type
to set margins. type is a name listed in term(M).
If no -T flag is supplied, tabs uses the value of
the environment variable TERM. If TERM is not
defined in the environment [see environ(M)], tabs
tries a sequence that will work for many terminals.
+mn The margin argument may be used for some terminals.
It causes all tabs to be moved over n columns by
making column n+1 the left margin. If +m is given
without a value of 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. The normal (leftmost) margin on most
terminals is obtained by +m0. The margin for most
terminals is reset only when the +m flag is given
explicitly.
Tab and margin setting is performed via the standard output.
Examples
tabs -a example using -code (canned specification) to
set tabs to the settings required by the IBM
assembler: columns 1, 10, 16, 36, 72.
tabs -8 example of using -n (repetitive specification),
where n is 8, causes tabs to be set every
eighth position:
1+(1*8), 1+(2*8), ... which evaluate to columns
9, 17, ...
tabs 1,8,36 example of using n1,n2,... (arbitrary
specification) to set tabs at columns 1, 8, and
36.
tabs --$HOME/fspec.list/att4425
example of using --file (file specification) to
indicate that tabs should be set according to
the first line of $HOME/fspec.list/att4425 [see
fspec(F)].
Diagnostics
illegal tabs when arbitrary tabs are ordered
incorrectly
illegal increment when a zero or missing increment is
found in an arbitrary specification
unknown tab code when a canned code cannot be found
can't open if --file option used and file can't be
opened
file indirection if --file option used and the
specification in that file points to yet
another file. Indirection of this form
is not permitted
See Also
newform(C), pr(C), tput(C), fspec(F), terminfo(F),
environ(M), term(M)
Notes
There is no consistency among different terminals regarding
ways of clearing tabs and setting the left margin.
tabs clears only 20 tabs (on terminals requiring a long
sequence), but is willing to set 64.
The tabspec used with the tabs command is different from the
one used with the newform(C) command. For example, tabs -8
sets every eighth position; whereas newform -i-8 indicates
that tabs are set every eighth position.
Standards Conformance
tabs is conformant with:
AT&T SVID Issue 2, Select Code 307-127;
and The X/Open Portability Guide II of January 1987.
(printed 9/19/89) TABS(C)