tabs - set tabs on a terminal
tabs [tabspec] [-Ttype] [+mn]
tabs 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., UNIX system ``standard'' 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
-code Use one of the codes listed below to select a canned set of tabs.
The legal codes and their meanings are as follows:
Assembler, IBM S/370, first format
Assembler, IBM S/370, second format
COBOL, normal format
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(4)):
<:t-c2 m6 s66 d:>
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(4)):
<:t-c3 m6 s66 d:>
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 UNIX system ``standard'' 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.
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(4)). 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(1) 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(5). 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(5)), 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
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.
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(4)).
illegal tabs when arbitrary tabs are ordered incorrectly
illegal increment when a zero or missing increment is found in an
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
Hardware tabs must be enabled on the terminal device by entering the UNIX
command `stty tabs'; otherwise the tabs command will appear to have no
effect. Tab and margin setting is performed via the standard output.
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(1) command. For example, tabs -8 sets every eighth
position; whereas newform -i-8 indicates that tabs are set every eighth
stty(1), newform(1), pr(1), tput(1), fspec(4), terminfo(4), environ(5),
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