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<h3 class="section">11.11 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,
<pre class="example"> my_command hello world
</pre>
<p class="noindent">is equivalent to
<pre class="example"> my_command("hello", "world")
</pre>
<p class="noindent">The general form of a command call is
<pre class="example"> <var>cmdname</var> <var>arg1</var> <var>arg2</var> ...
</pre>
<p class="noindent">which translates directly to
<pre class="example"> <var>cmdname</var> ("<var>arg1</var>", "<var>arg2</var>", ...)
</pre>
<p>Any regular function can be used as a command if it accepts string input
arguments. For example:
<pre class="example"> toupper lower_case_arg
⇒ ans = LOWER_CASE_ARG
</pre>
<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:
<pre class="example"> strvar = "hello world";
toupper strvar
⇒ ans = STRVAR
toupper (strvar)
⇒ ans = HELLO WORLD
</pre>
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