php怎么样变量到一定时间清理？php中session定期自动清理的方法

[root@hz scripts]# grep"session.save_path = "/usr/local/php/lib/php.ini

;   session.save_path ="N;/path"

;   session.save_path ="N;MODE;/path"

;session.save_path ="/tmp"

session.save_path ="2;/tmp/session"

[root@hz ~]# cat /byrd/script/Cleartmpsen.sh

#!/bin/bash

# Version:1.0

# Author:Byrd

# Site:www.t4x.org

# Contact:root#t4x.org

# This is script will clear php session before 3 hours.

i="0 1 2 3 4 5 6 7 8 9 a b c d e f"

forbyrd in$i;

do

  forx in$i;

  do

    mkdir-p /tmp/session/$byrd/$x;

  done;

done

chown-R bywww:bywww /tmp/session

chmod-R 1777 /tmp/session

find /tmp/session -amin +180 -execrm -rf {} ＼;

if[ `grep'session.save_path ='/usr/local/php/lib/php.ini | wc -l` -eq 3 ];then

  sed -i's#;session.save_path = "/tmp"#;session.save_path = "/tmp"＼nsession.save_path = "2;/tmp/session"#g'/usr/local/php/lib/php.ini

else

  exit1

fi