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<h4 class="subsection">2.4.7 Customizing the Prompt</h4>
<p><a name="index-prompt-customization-155"></a><a name="index-customizing-the-prompt-156"></a>
The following variables are available for customizing the appearance of
the command-line prompts. Octave allows the prompt to be customized by
inserting a number of backslash-escaped special characters that are
decoded as follows:
<dl>
<dt>‘<samp><span class="samp">\t</span></samp>’<dd>The time.
<br><dt>‘<samp><span class="samp">\d</span></samp>’<dd>The date.
<br><dt>‘<samp><span class="samp">\n</span></samp>’<dd>Begins a new line by printing the equivalent of a carriage return
followed by a line feed.
<br><dt>‘<samp><span class="samp">\s</span></samp>’<dd>The name of the program (usually just ‘<samp><span class="samp">octave</span></samp>’).
<br><dt>‘<samp><span class="samp">\w</span></samp>’<dd>The current working directory.
<br><dt>‘<samp><span class="samp">\W</span></samp>’<dd>The basename of the current working directory.
<br><dt>‘<samp><span class="samp">\u</span></samp>’<dd>The username of the current user.
<br><dt>‘<samp><span class="samp">\h</span></samp>’<dd>The hostname, up to the first `.'.
<br><dt>‘<samp><span class="samp">\H</span></samp>’<dd>The hostname.
<br><dt>‘<samp><span class="samp">\#</span></samp>’<dd>The command number of this command, counting from when Octave starts.
<br><dt>‘<samp><span class="samp">\!</span></samp>’<dd>The history number of this command. This differs from ‘<samp><span class="samp">\#</span></samp>’ by the
number of commands in the history list when Octave starts.
<br><dt>‘<samp><span class="samp">\$</span></samp>’<dd>If the effective UID is 0, a ‘<samp><span class="samp">#</span></samp>’, otherwise a ‘<samp><span class="samp">$</span></samp>’.
<br><dt>‘<samp><span class="samp">\nnn</span></samp>’<dd>The character whose character code in octal is <var>nnn</var>.
<br><dt>‘<samp><span class="samp">\\</span></samp>’<dd>A backslash.
</dl>
<!-- PS1 src/input.cc -->
<p><a name="doc_002dPS1"></a>
<div class="defun">
— Built-in Function: <var>val</var> = <b>PS1</b> ()<var><a name="index-PS1-157"></a></var><br>
— Built-in Function: <var>old_val</var> = <b>PS1</b> (<var>new_val</var>)<var><a name="index-PS1-158"></a></var><br>
— Built-in Function: <b>PS1</b> (<var>new_val, "local"</var>)<var><a name="index-PS1-159"></a></var><br>
<blockquote><p>Query or set the primary prompt string. When executing interactively,
Octave displays the primary prompt when it is ready to read a command.
<p>The default value of the primary prompt string is <code>"\s:\#> "</code>.
To change it, use a command like
<pre class="example"> PS1 ("\\u@\\H> ")
</pre>
<p class="noindent">which will result in the prompt ‘<samp><span class="samp">boris@kremvax> </span></samp>’ for the user
‘<samp><span class="samp">boris</span></samp>’ logged in on the host ‘<samp><span class="samp">kremvax.kgb.su</span></samp>’. Note that two
backslashes are required to enter a backslash into a double-quoted
character string. See <a href="Strings.html#Strings">Strings</a>.
<p>You can also use ANSI escape sequences if your terminal supports them.
This can be useful for coloring the prompt. For example,
<pre class="example"> PS1 ("\\[\\033[01;31m\\]\\s:\\#> \\[\\033[0m\\]")
</pre>
<p class="noindent">will give the default Octave prompt a red coloring.
<p>When called from inside a function with the "local" option, the variable is
changed locally for the function and any subroutines it calls. The original
variable value is restored when exiting the function.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dPS2.html#doc_002dPS2">PS2</a>, <a href="doc_002dPS4.html#doc_002dPS4">PS4</a>.
</p></blockquote></div>
<!-- PS2 src/input.cc -->
<p><a name="doc_002dPS2"></a>
<div class="defun">
— Built-in Function: <var>val</var> = <b>PS2</b> ()<var><a name="index-PS2-160"></a></var><br>
— Built-in Function: <var>old_val</var> = <b>PS2</b> (<var>new_val</var>)<var><a name="index-PS2-161"></a></var><br>
— Built-in Function: <b>PS2</b> (<var>new_val, "local"</var>)<var><a name="index-PS2-162"></a></var><br>
<blockquote><p>Query or set the secondary prompt string. The secondary prompt is
printed when Octave is expecting additional input to complete a
command. For example, if you are typing a <code>for</code> loop that spans several
lines, Octave will print the secondary prompt at the beginning of
each line after the first. The default value of the secondary prompt
string is <code>"> "</code>.
<p>When called from inside a function with the "local" option, the variable is
changed locally for the function and any subroutines it calls. The original
variable value is restored when exiting the function.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dPS1.html#doc_002dPS1">PS1</a>, <a href="doc_002dPS4.html#doc_002dPS4">PS4</a>.
</p></blockquote></div>
<!-- PS4 src/input.cc -->
<p><a name="doc_002dPS4"></a>
<div class="defun">
— Built-in Function: <var>val</var> = <b>PS4</b> ()<var><a name="index-PS4-163"></a></var><br>
— Built-in Function: <var>old_val</var> = <b>PS4</b> (<var>new_val</var>)<var><a name="index-PS4-164"></a></var><br>
— Built-in Function: <b>PS4</b> (<var>new_val, "local"</var>)<var><a name="index-PS4-165"></a></var><br>
<blockquote><p>Query or set the character string used to prefix output produced
when echoing commands is enabled.
The default value is <code>"+ "</code>.
See <a href="Diary-and-Echo-Commands.html#Diary-and-Echo-Commands">Diary and Echo Commands</a>, for a description of echoing commands.
<p>When called from inside a function with the "local" option, the variable is
changed locally for the function and any subroutines it calls. The original
variable value is restored when exiting the function.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002decho.html#doc_002decho">echo</a>, <a href="doc_002decho_005fexecuting_005fcommands.html#doc_002decho_005fexecuting_005fcommands">echo_executing_commands</a>, <a href="doc_002dPS1.html#doc_002dPS1">PS1</a>, <a href="doc_002dPS2.html#doc_002dPS2">PS2</a>.
</p></blockquote></div>
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