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- * @Id: tabs.1,v 1.25 2019/06/15 23:08:12 tom Exp @
+ * @Id: tabs.1,v 1.27 2020/02/02 23:34:34 tom Exp @
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The <STRONG>-d</STRONG> (debug) and <STRONG>-n</STRONG> (no-op) options are extensions not provided by
other implementations.
- A <STRONG>tabs</STRONG> utility appeared in PWB/Unix 1.0 (1977), and thereafter in 3BSD
- (1979). It supported a single "-n" option (to cause the first tab stop
+ A <STRONG>tabs</STRONG> utility appeared in PWB/Unix 1.0 (1977). There was a reduced
+ version of the <STRONG>tabs</STRONG> utility in Unix 7th edition and in 3BSD (1979).
+ The latter supported a single "-n" option (to cause the first tab stop
to be set on the left margin). That option is not documented by POSIX.
- Initially, <STRONG>tabs</STRONG> used built-in tables rather than the terminal database,
- to support a half-dozen terminal types. It also had built-in logic to
- support the left-margin, as well as a feature for copying the tab set-
- tings from a file.
-
- Later versions of Unix, e.g., SVr4, added support for the terminal
- database, but kept the tables, as a fallback. In an earlier develop-
- ment effort, the tab-stop initialization provided by <STRONG>tset</STRONG> (1982) and
+
+ The PWB/Unix <STRONG>tabs</STRONG> utility, which was included in System III (1980),
+ used built-in tables rather than the terminal database, to support a
+ half-dozen terminal types. It also had built-in logic to support the
+ left-margin, as well as a feature for copying the tab settings from a
+ file.
+
+ Later versions of Unix, e.g., SVr4, added support for the terminal
+ database, but kept the tables, as a fallback. In an earlier develop-
+ ment effort, the tab-stop initialization provided by <STRONG>tset</STRONG> (1982) and
incorporated into <STRONG>tput</STRONG> uses the terminal database,
- POSIX documents no limits on the number of tab stops. Documentation
+ POSIX documents no limits on the number of tab stops. Documentation
for other implementations states that there is a limit on the number of
- tab stops. While some terminals may not accept an arbitrary 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.
+ tab stops (e.g., 20 in PWB/Unix's <STRONG>tabs</STRONG> utility). While some terminals
+ may not accept an arbitrary 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.
The <EM>Rationale</EM> section of the POSIX documentation goes into some detail
about the ways the committee considered redesigning the <STRONG>tabs</STRONG> and <STRONG>tput</STRONG>
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
<STRONG><A HREF="tset.1.html">tset(1)</A></STRONG>, <STRONG><A HREF="infocmp.1m.html">infocmp(1m)</A></STRONG>, <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>.
- This describes <STRONG>ncurses</STRONG> version 6.1 (patch 20190615).
+ This describes <STRONG>ncurses</STRONG> version 6.2 (patch 20201031).