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<a name="Commands"></a>
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Next: <a href="Organization-of-Functions.html#Organization-of-Functions" accesskey="n" rel="next">Organization of Functions</a>, Previous: <a href="Function-Handles-Anonymous-Functions-Inline-Functions.html#Function-Handles-Anonymous-Functions-Inline-Functions" accesskey="p" rel="prev">Function Handles Anonymous Functions Inline Functions</a>, Up: <a href="Functions-and-Scripts.html#Functions-and-Scripts" accesskey="u" rel="up">Functions and Scripts</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Commands-1"></a>
<h3 class="section">11.12 Commands</h3>
<p>Commands are a special class of functions that only accept string
input arguments. A command can be called as an ordinary function, but
it can also be called without the parentheses. For example,
</p>
<div class="example">
<pre class="example">my_command hello world
</pre></div>
<p>is equivalent to
</p>
<div class="example">
<pre class="example">my_command ("hello", "world")
</pre></div>
<p>The general form of a command call is
</p>
<div class="example">
<pre class="example"><var>cmdname</var> <var>arg1</var> <var>arg2</var> …
</pre></div>
<p>which translates directly to
</p>
<div class="example">
<pre class="example"><var>cmdname</var> ("<var>arg1</var>", "<var>arg2</var>", …)
</pre></div>
<p>Any regular function can be used as a command if it accepts string input
arguments. For example:
</p>
<div class="example">
<pre class="example">toupper lower_case_arg
⇒ ans = LOWER_CASE_ARG
</pre></div>
<p>One difficulty of commands occurs when one of the string input arguments
is stored in a variable. Because Octave can’t tell the difference between
a variable name and an ordinary string, it is not possible to pass a
variable as input to a command. In such a situation a command must be
called as a function. For example:
</p>
<div class="example">
<pre class="example">strvar = "hello world";
toupper strvar
⇒ ans = STRVAR
toupper (strvar)
⇒ ans = HELLO WORLD
</pre></div>
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