关于日志的清理~~~

smit.log  文件是节格式的，截取部分如下，怎样删除 "Oct 12 2011"这个日期的全部记录，而不是只删除“Oct 12 2011”这一行~~~~
谢谢！

[Oct 12 2011, 23:32:07]
Starting Motif SMIT
(Menu screen selected,
FastPath    = "inet",
id_seq_num  = "010",
next_id     = "inet",
title       = "Network Interface Selection".)
(Selector screen selected,
FastPath  = "chinet",
id        = "chinet",
next_id   = "chinet",
title     = "Change / Show Characteristics of a Network Interface".)
(Selector screen selected,
FastPath  = "chinet",
id        = "chinet",
next_id   = "chinet",
title     = "Change / Show Characteristics of a Network Interface".)
(Dialogue screen selected,
FastPath    = "chinet",
id          = "chineten",
title       = "Change / Show a Standard Ethernet Interface".)
(Selector screen selected,
FastPath  = "chinet",
id        = "chinet",
next_id   = "chinet",
title     = "Change / Show Characteristics of a Network Interface".)
(Selector screen selected,
FastPath  = "chinet",
id        = "chinet",
next_id   = "chinet",
title     = "Change / Show Characteristics of a Network Interface".)
[Oct 12 2011, 23:32:59]
Stopping Motif SMIT
[Oct 12 2011, 23:33:06]
Starting Motif SMIT
(Menu screen selected,
FastPath    = "tcpip",
id_seq_num  = "010",
next_id     = "tcpip",
title       = "TCP/IP".)
(Selector screen selected,
FastPath  = "mktcpip",
id        = "mktcpip",
next_id   = "mktcpip",
title     = "Minimum Configuration & Startup".)
(Selector screen selected,
FastPath  = "mktcpip",
id        = "mktcpip",
next_id   = "mktcpip",
title     = "Minimum Configuration & Startup".)
(Dialogue screen selected,
FastPath    = "mktcpip",
id          = "mktcpipen",
title       = "Minimum Configuration & Startup
To Delete existing configuration data, please use Further Configuration menus".)
(Selector screen selected,
FastPath  = "mktcpip",
id        = "mktcpip",
next_id   = "mktcpip",
title     = "Minimum Configuration & Startup"