xref: /freebsd/usr.bin/tabs/tabs.1 (revision fa9896e082a1046ff4fbc75fcba4d18d1f2efc19)

.\" Copyright (c) 2002 Tim J. Robbins.
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.Dd September 9, 2021
.Dt TABS 1
.Os
.Sh NAME
.Nm tabs
.Nd set terminal tabs
.Sh SYNOPSIS
.Nm
.Op Fl Ar n | Fl a | a2 | c | c2 | c3 | f | p | s | u
.Op Cm +m Ns Op Ar n
.Op Fl T Ar type
.Nm
.Op Fl T Ar type
.Op Cm + Ns Op Ar n
.Ar n1 Ns Op Ns , Ns Ar n2 , Ns ...
.Sh DESCRIPTION
The
.Nm
utility displays a series of characters that clear the hardware terminal
tab settings then initialises tab stops at specified positions, and
optionally adjusts the margin.
.Pp
In the first synopsis form, the tab stops set depend on the command line
options used, and may be one of the predefined formats or at regular
intervals.
.Pp
In the second synopsis form, tab stops are set at positions
.Ar n1 , n2 ,
etc.
If a position is preceded by a
.Ql + ,
it is relative to the previous position set.
No more than 20 positions may be specified.
.Pp
If no tab stops are specified, the
.Dq standard
.Ux
tab width of 8 is used.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl Ar n
Set a tab stop every
.Ar n
columns.
If
.Ar n
is 0, the tab stops are cleared but no new ones are set.
.It Fl a
Assembler format (columns 1, 10, 16, 36, 72).
.It Fl a2
Assembler format (columns 1, 10, 16, 40, 72).
.It Fl c
.Tn COBOL
normal format (columns 1, 8, 12, 16, 20, 55)
.It Fl c2
.Tn COBOL
compact format (columns 1, 6, 10, 14, 49)
.It Fl c3
.Tn COBOL
compact format (columns 1, 6, 10, 14, 18, 22, 26, 30, 34, 38, 42, 46,
50, 54, 58, 62, 67).
.It Fl f
.Tn FORTRAN
format (columns 1, 7, 11, 15, 19, 23).
.It Fl p
.Tn PL/1
format (columns 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53,
57, 61).
.It Fl s
.Tn SNOBOL
format (columns 1, 10, 55).
.It Fl u
Assembler format (columns 1, 12, 20, 44).
.It Xo
.Cm +m Ns Op Ar n ,
.Cm + Ns Op Ar n
.Xc
Set an
.Ar n
character left margin, or 10 if
.Ar n
is omitted.
.It Fl T Ar type
Output escape sequence for the terminal type
.Ar type .
.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 .
.Pp
The
.Fl T
option overrides the setting of the
.Ev TERM
environment variable.
If neither
.Ev TERM
nor the
.Fl T
option are present,
.Nm
will fail.
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr expand 1 ,
.Xr stty 1 ,
.Xr tput 1 ,
.Xr unexpand 1 ,
.Xr termcap 5
.Sh STANDARDS
The
.Nm
utility conforms to
.St -p1003.1-2001 .
.Sh HISTORY
.Pa /etc/tabs
appeared in
.At v1
which set tabs every 8 on Teletype model 37 and compatible printing terminals
when printed.
A
.Nm
utility that worked on many terminals appeared in PWB UNIX.
This implementation was introduced in
.Fx 5.0 .
.Sh BUGS
The current
.Xr termcap 5
database does not define the
.Ql ML
(set left soft margin) capability for any terminals.