ch41_11.htm

the unix power tools

CLASS="term"
><EM
CLASS="emphasis"
>up=^K</EM
></DT
><DT
CLASS="term"
><EM
CLASS="emphasis"
>cuu1=^K</EM
></DT
><DD
CLASS="listitem"
><P
CLASS="para"
>is the up capability; it says that to move the cursor up one line,
send the <CODE
CLASS="literal"
>^K</CODE
> character to the terminal.</P
></DD
><DT
CLASS="term"
><EM
CLASS="emphasis"
>cl=^Z</EM
></DT
><DT
CLASS="term"
><EM
CLASS="emphasis"
>clear=^Z</EM
></DT
><DD
CLASS="listitem"
><P
CLASS="para"
>is the clear capability; it says that to clear the screen,
send the <CODE
CLASS="literal"
>^Z</CODE
> character to the terminal.</P
></DD
><DT
CLASS="term"
><EM
CLASS="emphasis"
>ho=^^</EM
></DT
><DT
CLASS="term"
><EM
CLASS="emphasis"
>home=^^</EM
></DT
><DD
CLASS="listitem"
><P
CLASS="para"
>is the home capability;  it says that to move the cursor Home (upper-left corner), send the <CODE
CLASS="literal"
>^^</CODE
> character (CTRL-<CODE
CLASS="literal"
>^</CODE
>) to the terminal.</P
></DD
><DT
CLASS="term"
><EM
CLASS="emphasis"
>nd=^L</EM
></DT
><DT
CLASS="term"
><EM
CLASS="emphasis"
>cuf1=^L</EM
></DT
><DD
CLASS="listitem"
><P
CLASS="para"
>&#13;is the non-destructive space capability; it says that to move the cursor one
space to the right without changing the text, 
send the <CODE
CLASS="literal"
>^L</CODE
> character to the terminal.</P
></DD
></DL
><DIV
CLASS="sect2"
><H3
CLASS="sect2"
><A
CLASS="title"
NAME="UPT-ART-7967-SECT-1.0.1"
>41.11.1 Special Character Codes </A
></H3
><P
CLASS="para"
><A
CLASS="indexterm"
NAME="AUTOID-46295"
></A
><A
CLASS="indexterm"
NAME="AUTOID-46297"
></A
>No doubt the symbols <CODE
CLASS="literal"
>^K</CODE
>, <CODE
CLASS="literal"
>^Z</CODE
>, <CODE
CLASS="literal"
>^^</CODE
>, and <CODE
CLASS="literal"
>^L</CODE
> 
shown above are familiar to you.
A caret (<CODE
CLASS="literal"
>^</CODE
>) followed by a letter is a convention for representing 
an unprintable control character generated by holding down the CONTROL
(CTRL) key on the keyboard while typing another.
Note that control characters
are entered into a terminal description as two characters by typing
the caret character (<CODE
CLASS="literal"
>^</CODE
>) followed by a letter, 
rather than by inserting the actual control character.</P
><P
CLASS="para"
><A
CLASS="indexterm"
NAME="AUTOID-46307"
></A
>Both <EM
CLASS="emphasis"
>termcap</EM
> and <EM
CLASS="emphasis"
>terminfo</EM
> use other codes to write other 
unprintable characters, as well as characters that have special meaning
in <EM
CLASS="emphasis"
>termcap</EM
> or <EM
CLASS="emphasis"
>terminfo</EM
> syntax.
The other
<A
CLASS="indexterm"
NAME="AUTOID-46314"
></A
>
codes, most of which should be familiar to C programmers, 
are listed in
<A
CLASS="xref"
HREF="ch41_11.htm#UPT-ART-7967-TAB-0"
TITLE="Termcap and Terminfo Special Character Codes"
>Table 41.1</A
>.&#13;</P
><TABLE
CLASS="table"
><CAPTION
CLASS="table"
><A
CLASS="title"
NAME="UPT-ART-7967-TAB-0"
>Table 41.1: Termcap and Terminfo Special Character Codes</A
></CAPTION
><THEAD
CLASS="thead"
><TR
CLASS="row"
VALIGN="TOP"
><TH
CLASS="entry"
ALIGN="LEFT"
ROWSPAN="1"
COLSPAN="1"
>Code</TH
><TH
CLASS="entry"
ALIGN="LEFT"
ROWSPAN="1"
COLSPAN="1"
>Description</TH
><TH
CLASS="entry"
ALIGN="LEFT"
ROWSPAN="1"
COLSPAN="1"
>Comment</TH
></TR
></THEAD
><TBODY
CLASS="tbody"
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\E</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>escape</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>termcap and terminfo</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\e</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>escape</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>^<CODE
CLASS="userinput"
><B
>x</B
></CODE
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>control-<CODE
CLASS="userinput"
><B
>x</B
></CODE
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>where <CODE
CLASS="userinput"
><B
>x</B
></CODE
> is any letter</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\n</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>newline</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\r</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>return</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\t</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>tab</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\b</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>backspace</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\f</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>formfeed</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\s</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>space</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\l</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>linefeed</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\<CODE
CLASS="userinput"
><B
>xxx</B
></CODE
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>octal value of <CODE
CLASS="userinput"
><B
>xxx</B
></CODE
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>must be three characters</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\041</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>exclamation point <CODE
CLASS="literal"
>!</CODE
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>C shell history uses <CODE
CLASS="literal"
>!</CODE
></TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\072</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>the character <CODE
CLASS="literal"
>:</CODE
></TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>termcap uses ordinary : as separator</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\200</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>null</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\\000 for null does not work</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\0</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>null</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\^</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>caret</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\\</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>backslash</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\,</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>comma</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
><TR
CLASS="row"
VALIGN="TOP"
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>\:</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>colon</TD
><TD
CLASS="entry"
ROWSPAN="1"
COLSPAN="1"
>terminfo only</TD
></TR
></TBODY
></TABLE
></DIV
><DIV
CLASS="sect2"
><H3
CLASS="sect2"
><A
CLASS="title"
NAME="UPT-ART-7967-SECT-1.0.2"
>41.11.2 Encoding Arguments </A
></H3
><P
CLASS="para"
>The last capability in the Wyse-50 example is the most complicated.
<EM
CLASS="emphasis"
>cm=</EM
> (<EM
CLASS="emphasis"
>termcap</EM
>) and <EM
CLASS="emphasis"
>cup=</EM
> (<EM
CLASS="emphasis"
>terminfo</EM
>) 
specify the cursor motion capability, which describes how to move 
the cursor directly to a specific location.
Since the desired location is specified by the
program at run-time, the capability must provide
some mechanism for encoding arguments.
The program uses this
description to figure out what string it needs to send to move the
cursor to the desired location.</P
><P
CLASS="para"
><A
CLASS="indexterm"
NAME="AUTOID-46418"
></A
>Because we aren't telling you how to write <EM
CLASS="emphasis"
>termcap</EM
> or 
<EM
CLASS="emphasis"
>terminfo</EM
> entries, but just to read them, all you need to know
is that the percent sign (<CODE
CLASS="literal"
>%</CODE
>) is used for
encoding, and when it appears in a terminal entry, the capability is
using run-time parameters.</P
><P
CLASS="para"
>If you need to write an entry, see O'Reilly &amp; Associates' <EM
CLASS="emphasis"
>termcap
&amp; terminfo</EM
>.</P
></DIV
><DIV
CLASS="sect1info"
><P
CLASS="SECT1INFO"
>- <SPAN
CLASS="authorinitials"
>JS</SPAN
>, <SPAN
CLASS="authorinitials"
>TOR</SPAN
></P
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