>Description</h3>
<p>Executes a system command. When the <i>os</i> attribute is specified, then
the command is only executed when Apache Ant is run on one of the specified operating
systems.</p>

<p>Note that you cannot interact with the forked program, the only way
to send input to it is via the input and inputstring attributes. Also note that
since Ant 1.6, any attempt to read input in the forked program will receive an
EOF (-1). This is a change from Ant 1.5, where such an attempt would block.</p>

<p>If