/**    Method to execute a command in the terminal    Uses :     1. system    2. passthru    3. exec    4. shell_exec */function terminal($command){    //system    if(function_exists('system'))    {        ob_start();        system($command , $return_var);        $output = ob_get_contents();        ob_end_clean();    }    //passthru    else if(function_exists('passthru'))    {        ob_start();        passthru($command , $return_var);        $output = ob_get_contents();        ob_end_clean();    }     //exec    else if(function_exists('exec'))    {        exec($command , $output , $return_var);        $output = implode("n" , $output);    }     //shell_exec    else if(function_exists('shell_exec'))    {        $output = shell_exec($command) ;    }     else    {        $output = 'Command execution not possible on this system';        $return_var = 1;    }     return array('output' => $output , 'status' => $return_var);}terminal('ls');