+</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
+ The <STRONG>tput</STRONG> command was begun by Bill Joy in 1980. The ini-
+ tial version only cleared the screen.
+
+ AT&T System V provided a different <STRONG>tput</STRONG> command, whose
+ <STRONG>init</STRONG> and <STRONG>reset</STRONG> subcommands (more than half the program)
+ were incorporated from the <STRONG>reset</STRONG> feature of BSD <STRONG>tset</STRONG> writ-
+ ten by Eric Allman. Later the corresponding source code
+ for <EM>reset</EM> was removed from the BSD <STRONG>tset</STRONG> (in June 1993,
+ released in 4.4BSD-Lite a year later).
+
+ Keith Bostic replaced the BSD <STRONG>tput</STRONG> command in 1989 with a
+ new implementation based on the AT&T System V program
+ <STRONG>tput</STRONG>. Like the AT&T program, Bostic's version accepted
+ some parameters named for <EM>terminfo</EM> <EM>capabilities</EM> (<STRONG>clear</STRONG>,
+ <STRONG>init</STRONG>, <STRONG>longname</STRONG> and <STRONG>reset</STRONG>). However (because he had only
+ termcap available), it accepted <EM>termcap</EM> <EM>names</EM> for other
+ capabilities. Also, Bostic's BSD <STRONG>tput</STRONG> did not modify the
+ terminal I/O modes as the earlier BSD <STRONG>tset</STRONG> had done.
+
+ At the same time, Bostic added a shell script named
+ "clear", which used <STRONG>tput</STRONG> to clear the screen.
+
+ Both of these appeared in 4.4BSD, becoming the "modern"
+ BSD implementation of <STRONG>tput</STRONG>.
+
+
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ This implementation of <STRONG>tput</STRONG> differs from AT&T <STRONG>tput</STRONG> in two
+ important areas:
+
+ <STRONG>o</STRONG> tput <EM>capname</EM> writes to the standard output. That need
+ not be a regular terminal. However, the subcommands
+ which manipulate terminal modes may not use the stan-
+ dard output.
+
+ The AT&T implementation's <STRONG>init</STRONG> and <STRONG>reset</STRONG> commands use
+ the BSD (4.1c) <STRONG>tset</STRONG> source, which manipulates terminal
+ modes. It successively tries standard output, stan-
+ dard error, standard input before falling back to
+ "/dev/tty" and finally just assumes a 1200Bd terminal.
+ When updating terminal modes, it ignores errors.
+
+ Until changes made after ncurses 6.0, tput did not
+ modify terminal modes. tput now uses a similar
+ scheme, using functions shared with tset (and ulti-
+ mately based on the 4.4BSD <STRONG>tset</STRONG>). If it is not able
+ to open a terminal, e.g., when running in <STRONG>cron</STRONG>, tput
+ will return an error.
+
+ <STRONG>o</STRONG> AT&T <STRONG>tput</STRONG> guesses the type of its <EM>capname</EM> operands by
+ seeing if all of the characters are numeric, or not.
+
+ Most implementations which provide support for <EM>capname</EM>
+ operands use the <EM>tparm</EM> function to expand parameters
+ in it. That function expects a mixture of numeric and
+ string parameters, requiring <STRONG>tput</STRONG> to know which type
+ to use.
+
+ This implementation uses a table to determine the
+ parameter types for the standard <EM>capname</EM> operands, and
+ an internal library function to analyze nonstandard
+ <EM>capname</EM> operands.
+
+ The <STRONG>longname</STRONG> and <STRONG>-S</STRONG> options, and the parameter-substitu-
+ tion features used in the <STRONG>cup</STRONG> example, were not supported
+ in BSD curses before 4.3reno (1989) or in AT&T/USL curses
+ before SVr4 (1988).
+
+ IEEE Std 1003.1/The Open Group Base Specifications Issue
+ 7 (POSIX.1-2008) documents only the operands for <STRONG>clear</STRONG>,
+ <STRONG>init</STRONG> and <STRONG>reset</STRONG>. There are a few interesting observations
+ to make regarding that:
+
+ <STRONG>o</STRONG> In this implementation, <STRONG>clear</STRONG> is part of the <EM>capname</EM>
+ support. The others (<STRONG>init</STRONG> and <STRONG>longname</STRONG>) do not corre-
+ spond to terminal capabilities.
+
+ <STRONG>o</STRONG> Other implementations of <STRONG>tput</STRONG> on SVr4-based systems
+ such as Solaris, IRIX64 and HPUX as well as others
+ such as AIX and Tru64 provide support for <EM>capname</EM> op-
+ erands.
+
+ <STRONG>o</STRONG> A few platforms such as FreeBSD recognize termcap
+ names rather than terminfo capability names in their
+ respective <STRONG>tput</STRONG> commands. Since 2010, NetBSD's <STRONG>tput</STRONG>
+ uses terminfo names. Before that, it (like FreeBSD)
+ recognized termcap names.
+
+ Because (apparently) <EM>all</EM> of the certified Unix systems
+ support the full set of capability names, the reasoning
+ for documenting only a few may not be apparent.
+
+ <STRONG>o</STRONG> X/Open Curses Issue 7 documents <STRONG>tput</STRONG> differently, with
+ <EM>capname</EM> and the other features used in this implemen-
+ tation.
+
+ <STRONG>o</STRONG> That is, there are two standards for <STRONG>tput</STRONG>: POSIX (a
+ subset) and X/Open Curses (the full implementation).
+ POSIX documents a subset to avoid the complication of
+ including X/Open Curses and the terminal capabilities
+ database.
+
+ <STRONG>o</STRONG> While it is certainly possible to write a <STRONG>tput</STRONG> program
+ without using curses, none of the systems which have a
+ curses implementation provide a <STRONG>tput</STRONG> utility which
+ does not provide the <EM>capname</EM> feature.
+
+
+</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+ <STRONG><A HREF="clear.1.html">clear(1)</A></STRONG>, <STRONG>stty(1)</STRONG>, <STRONG><A HREF="tabs.1.html">tabs(1)</A></STRONG>, <STRONG><A HREF="tset.1.html">tset(1)</A></STRONG>, <STRONG><A HREF="terminfo.5.html">terminfo(5)</A></STRONG>,
+ <STRONG><A HREF="curs_termcap.3x.html">curs_termcap(3x)</A></STRONG>.
+
+ This describes <STRONG>ncurses</STRONG> version 6.0 (patch 20160820).
+
+
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