tabs(1) General Commands Manual tabs(1)
tabs - set tabs on a terminal
tabs [options]] [tabstop-list]
The tabs program clears and sets tab-stops on the terminal. This uses the terminfo clear_all_tabs and set_tab capabilities. If either is absent, tabs is unable to clear/set tab-stops. The terminal should be configured to use hard tabs, e.g., stty tab0 Like clear(1), tabs writes to the standard output. You can redirect the standard output to a file (which prevents tabs from actually chang- ing the tabstops), and later cat the file to the screen, setting tab- stops at that point. These are hardware tabs, which cannot be queried rapidly by applica- tions running in the terminal, if at all. Curses and other full-screen applications may use hardware tabs in optimizing their output to the terminal. If the hardware tabstops differ from the information in the terminal database, the result is unpredictable.
-Tname Tell tabs which terminal type to use. If this option is not given, tabs will use the $TERM environment variable. If that is not set, it will use the ansi+tabs entry. -d The debugging option shows a ruler line, followed by two data lines. The first data line shows the expected tab-stops marked with asterisks. The second data line shows the actual tab-stops, marked with asterisks. -n This option tells tabs to check the options and run any debugging option, but not to modify the terminal settings. -V reports the version of ncurses which was used in this program, and exits. The tabs program processes a single list of tab stops. The last option to be processed which defines a list is the one that determines the list to be processed.
Use a single number as an option, e.g., "-5" to set tabs at the given interval (in this case 1, 6, 11, 16, 21, etc.). Tabs are repeated up to the right margin of the screen. Use "-0" to clear all tabs. Use "-8" to set tabs to the standard interval.
An explicit list can be defined after the options (this does not use a "-"). The values in the list must be in increasing numeric order, and greater than zero. They are separated by a comma or a blank, for exam- ple, tabs 1,6,11,16,21 tabs 1 6 11 16 21 Use a "+" to treat a number as an increment relative to the previous value, e.g., tabs 1,+5,+5,+5,+5 which is equivalent to the 1,6,11,16,21 example.
X/Open defines several predefined lists of tab stops. -a Assembler, IBM S/370, first format -a2 Assembler, IBM S/370, second format -c COBOL, normal format -c2 COBOL compact format -c3 COBOL compact format extended -f FORTRAN -p PL/I -s SNOBOL -u UNIVAC 1100 Assembler
IEEE Std 1003.1/The Open Group Base Specifications Issue 7 (POSIX.1-2008) describes a tabs utility. However o This standard describes a +m option, to set a terminal's left-mar- gin. Very few of the entries in the terminal database provide this capability. o There is no counterpart in X/Open Curses Issue 7 for this utility, unlike tput(1). The -d (debug) and -n (no-op) options are extensions not provided by other implementations. Documentation for other implementations states that there is a limit on the number of tab stops. While some terminals may not accept an arbi- trary number of tab stops, this implementation will attempt to set tab stops up to the right margin of the screen, if the given list happens to be that long.
tset(1), infocmp(1m), curses(3x), terminfo(5). This describes ncurses version 6.1 (patch 20190518). tabs(1)