ext-uv/examples/spawn.php

<?php

$in  = uv_pipe_init(uv_default_loop(), true);
$out = uv_pipe_init(uv_default_loop(), true);

echo "HELLO ";

$stdio = array();
$stdio[] = uv_stdio_new($in, UV::CREATE_PIPE | UV::READABLE_PIPE);
$stdio[] = uv_stdio_new($out, UV::CREATE_PIPE | UV::WRITABLE_PIPE);

$flags = 0;
uv_spawn(uv_default_loop(), "php", array('-r','var_dump($_ENV);'), $stdio, "/usr/bin/", 
    array("KEY"=>"hello"), 
    function($process, $stat, $signal){
	    uv_close($process,function(){});

}, $flags);

uv_read2_start($out, function($out, $nread, $buffer, $stat){
    echo $buffer;

    uv_close($out,function(){});
});

uv_run();