6. 通过redis命令使用示例：

    [xsky@localhost xhttpcache]$ redis-cli -p 7379
    127.0.0.1:7379> set test hello 
    OK
    127.0.0.1:7379> get test
    "hello"
    127.0.0.1:7379> set test hello ex 1000
    OK
    127.0.0.1:7379> get test
    "hello"
    127.0.0.1:7379> ttl test
    (integer) 988
    127.0.0.1:7379> EXPIRE test 2000
    (integer) 1
    127.0.0.1:7379> ttl test
    (integer) 1998
    127.0.0.1:7379> get test
    "hello"
    127.0.0.1:7379> 

redis-cli -p 7379 -x set getheadimg.jpg <getheadimg.jpg