PHP multi-process solves the problem of code resident in memory

#!/bin/env php
/**A example denoted muti-process application in php
* @filename fork.php
* @edit bbs.it-home.org
* @version 1.0.0
*/
/**Make sure this function can only be run in SHELL*/
if
(substr(php_sapi_name(), 0, 3) ! == 'cli')
{
die("This Programe can only be run in CLI mode");
}
/**Turn off the maximum execution event limit. In CLI mode, this statement is actually unnecessary.*/
set_time_limit(0);
$pid = posix_getpid(); / /Get the main process ID
$user = posix_getlogin(); //Get the user name
echo
<<USAGE: [command | expression]
input php code to execute by fork a new process
input quit to exit
Shell Executor version 1.0.0 by laruence
EOD;
while
(true)
{
$prompt = "n{$user}$ ";
$input = readline($prompt);
readline_add_history($input );
if
($input == 'quit')
{
break;
}
process_execute($input . ';');
}
exit(0);
function
process_execute($input)
{
$pid = pcntl_fork(); //Create child process
if
($pid == 0)
{//Subprocess
$pid = posix_getpid();
echo
"* Process {$pid} was created, and Executed:nn";
eval($input); //Parse the command
exit;
}
else
{//Main process
$pid = pcntl_wait($status, WUNTRACED); //Get the end status of the child process
 if
(pcntl_wifexited($status))
{
echo
"nn* Sub process: {$return['pid']} exited with {$status}";
}
}
}
?>

Please pay attention to the comments in the above code, which can help everyone understand and are also the essence of the code.