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<p>
Up: <a href="Terminal-Output.html" accesskey="u" rel="up">Terminal Output</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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<hr>
<h4 class="subsubsection" id="Paging-Screen-Output-1"><span>14.1.1.1 Paging Screen Output<a class="copiable-link" href="#Paging-Screen-Output-1"> ¶</a></span></h4>
<p>When running interactively, Octave normally sends all output directly to the
Command Window. However, when using the CLI version of Octave this can create
a problem because large volumes of data will stream by before you can read
them. In such cases, it is better to use a paging program such as <code class="code">less</code>
or <code class="code">more</code> which displays just one screenful at a time. With <code class="code">less</code>
(and some versions of <code class="code">more</code>) you can also scan forward and backward, and
search for specific items. The pager is enabled by the command <code class="code">more on</code>.
</p>
<p>Normally, no output is displayed by the pager until just before Octave is ready
to print the top level prompt, or read from the standard input (for example, by
using the <code class="code">fscanf</code> or <code class="code">scanf</code> functions). This means that there may
be some delay before any output appears on your screen if you have asked Octave
to perform a significant amount of work with a single command statement. The
function <code class="code">fflush</code> may be used to force output to be sent to the pager (or
any other stream) immediately.
</p>
<p>You can select the program to run as the pager with the <code class="code">PAGER</code> function,
and configure the pager itself with the <code class="code">PAGER_FLAGS</code> function.
</p>
<a class="anchor" id="XREFmore"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-more"><span><strong class="def-name">more</strong><a class="copiable-link" href="#index-more"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-more-1"><span><strong class="def-name">more</strong> <code class="def-code-arguments">on</code><a class="copiable-link" href="#index-more-1"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-more-2"><span><strong class="def-name">more</strong> <code class="def-code-arguments">off</code><a class="copiable-link" href="#index-more-2"> ¶</a></span></dt>
<dd><p>Turn output pagination on or off.
</p>
<p>Without an argument, <code class="code">more</code> toggles the current state.
</p>
<p>The current state can be determined via <code class="code">page_screen_output</code>.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="#XREFpage_005fscreen_005foutput">page_screen_output</a>, <a class="ref" href="#XREFpage_005foutput_005fimmediately">page_output_immediately</a>, <a class="ref" href="#XREFPAGER">PAGER</a>, <a class="ref" href="#XREFPAGER_005fFLAGS">PAGER_FLAGS</a>.
</p></dd></dl>
<a class="anchor" id="XREFPAGER"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-PAGER"><span><code class="def-type"><var class="var">val</var> =</code> <strong class="def-name">PAGER</strong> <code class="def-code-arguments">()</code><a class="copiable-link" href="#index-PAGER"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-PAGER-1"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">PAGER</strong> <code class="def-code-arguments">(<var class="var">new_val</var>)</code><a class="copiable-link" href="#index-PAGER-1"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-PAGER-2"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">PAGER</strong> <code class="def-code-arguments">(<var class="var">new_val</var>, "local")</code><a class="copiable-link" href="#index-PAGER-2"> ¶</a></span></dt>
<dd><p>Query or set the internal variable that specifies the program to use
to display terminal output on your system.
</p>
<p>The default value is normally <code class="code">"less"</code>, <code class="code">"more"</code>, or
<code class="code">"pg"</code>, depending on what programs are installed on your system.
See <a class="xref" href="Installation.html">Installing Octave</a>.
</p>
<p>When called from inside a function with the <code class="code">"local"</code> option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="#XREFPAGER_005fFLAGS">PAGER_FLAGS</a>, <a class="ref" href="#XREFpage_005foutput_005fimmediately">page_output_immediately</a>, <a class="ref" href="#XREFmore">more</a>, <a class="ref" href="#XREFpage_005fscreen_005foutput">page_screen_output</a>.
</p></dd></dl>
<a class="anchor" id="XREFPAGER_005fFLAGS"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-PAGER_005fFLAGS"><span><code class="def-type"><var class="var">val</var> =</code> <strong class="def-name">PAGER_FLAGS</strong> <code class="def-code-arguments">()</code><a class="copiable-link" href="#index-PAGER_005fFLAGS"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-PAGER_005fFLAGS-1"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">PAGER_FLAGS</strong> <code class="def-code-arguments">(<var class="var">new_val</var>)</code><a class="copiable-link" href="#index-PAGER_005fFLAGS-1"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-PAGER_005fFLAGS-2"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">PAGER_FLAGS</strong> <code class="def-code-arguments">(<var class="var">new_val</var>, "local")</code><a class="copiable-link" href="#index-PAGER_005fFLAGS-2"> ¶</a></span></dt>
<dd><p>Query or set the internal variable that specifies the options to pass
to the pager.
</p>
<p>When called from inside a function with the <code class="code">"local"</code> option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="#XREFPAGER">PAGER</a>, <a class="ref" href="#XREFmore">more</a>, <a class="ref" href="#XREFpage_005fscreen_005foutput">page_screen_output</a>, <a class="ref" href="#XREFpage_005foutput_005fimmediately">page_output_immediately</a>.
</p></dd></dl>
<a class="anchor" id="XREFpage_005fscreen_005foutput"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-page_005fscreen_005foutput"><span><code class="def-type"><var class="var">val</var> =</code> <strong class="def-name">page_screen_output</strong> <code class="def-code-arguments">()</code><a class="copiable-link" href="#index-page_005fscreen_005foutput"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-page_005fscreen_005foutput-1"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">page_screen_output</strong> <code class="def-code-arguments">(<var class="var">new_val</var>)</code><a class="copiable-link" href="#index-page_005fscreen_005foutput-1"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-page_005fscreen_005foutput-2"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">page_screen_output</strong> <code class="def-code-arguments">(<var class="var">new_val</var>, "local")</code><a class="copiable-link" href="#index-page_005fscreen_005foutput-2"> ¶</a></span></dt>
<dd><p>Query or set the internal variable that controls whether output intended
for the terminal window that is longer than one page is sent through a
pager.
</p>
<p>This allows you to view one screenful at a time. Some pagers
(such as <code class="code">less</code>—see <a class="pxref" href="Installation.html">Installing Octave</a>) are also capable of moving
backward on the output.
</p>
<p>When called from inside a function with the <code class="code">"local"</code> option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="#XREFmore">more</a>, <a class="ref" href="#XREFpage_005foutput_005fimmediately">page_output_immediately</a>, <a class="ref" href="#XREFPAGER">PAGER</a>, <a class="ref" href="#XREFPAGER_005fFLAGS">PAGER_FLAGS</a>.
</p></dd></dl>
<a class="anchor" id="XREFpage_005foutput_005fimmediately"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-page_005foutput_005fimmediately"><span><code class="def-type"><var class="var">val</var> =</code> <strong class="def-name">page_output_immediately</strong> <code class="def-code-arguments">()</code><a class="copiable-link" href="#index-page_005foutput_005fimmediately"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-page_005foutput_005fimmediately-1"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">page_output_immediately</strong> <code class="def-code-arguments">(<var class="var">new_val</var>)</code><a class="copiable-link" href="#index-page_005foutput_005fimmediately-1"> ¶</a></span></dt>
<dt class="deftypefnx def-cmd-deftypefn" id="index-page_005foutput_005fimmediately-2"><span><code class="def-type"><var class="var">old_val</var> =</code> <strong class="def-name">page_output_immediately</strong> <code class="def-code-arguments">(<var class="var">new_val</var>, "local")</code><a class="copiable-link" href="#index-page_005foutput_005fimmediately-2"> ¶</a></span></dt>
<dd><p>Query or set the internal variable that controls whether Octave sends
output to the pager as soon as it is available.
</p>
<p>When the value is <code class="code">false</code>, Octave buffers its output and waits until just
before the prompt is printed to flush it to the pager. This is the default.
</p>
<p>When <code class="code">page_screen_output</code> is <code class="code">false</code>, this variable has no effect.
</p>
<p>When called from inside a function with the <code class="code">"local"</code> option, the
variable is changed locally for the function and any subroutines it calls.
The original variable value is restored when exiting the function.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="#XREFpage_005fscreen_005foutput">page_screen_output</a>, <a class="ref" href="#XREFmore">more</a>, <a class="ref" href="#XREFPAGER">PAGER</a>, <a class="ref" href="#XREFPAGER_005fFLAGS">PAGER_FLAGS</a>.
</p></dd></dl>
<a class="anchor" id="XREFfflush"></a><span style="display:block; margin-top:-4.5ex;"> </span>
<dl class="first-deftypefn">
<dt class="deftypefn" id="index-fflush"><span><code class="def-type"><var class="var">status</var> =</code> <strong class="def-name">fflush</strong> <code class="def-code-arguments">(<var class="var">fid</var>)</code><a class="copiable-link" href="#index-fflush"> ¶</a></span></dt>
<dd><p>Flush output to file descriptor <var class="var">fid</var>.
</p>
<p><code class="code">fflush</code> returns 0 on success and an OS dependent error value
(−1 on Unix) on error.
</p>
<p>Programming Note: Flushing is useful for ensuring that all pending output
makes it to the screen before some other event occurs. For example, it is
always a good idea to flush the standard output stream before calling
<code class="code">input</code>.
</p>
<p><strong class="strong">See also:</strong> <a class="ref" href="Opening-and-Closing-Files.html#XREFfopen">fopen</a>, <a class="ref" href="Opening-and-Closing-Files.html#XREFfclose">fclose</a>.
</p></dd></dl>
</div>
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