awk RS regrex和RT

ubuntuer

RS分割符的妙用比比皆是,RS正则也见过,不过RT还真是第一次见^_^.给大家展示下RS regrex和RT.
               
               
                [root@mip blog]# cat TR_file
Sun Jan  2 07:42:56 2000
Database mounted in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
Sun Jan  2 07:42:56 2000
Database tested in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
abc Jan  2 12:42:56 2000
Database mounted in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
Sun Jan  2 23:00:00 2009
Database mounted in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
[root@mip blog]# awk -v RS='[[:alpha:]]+ [[:alpha:]]+  [0-9] [0-9][0-9]:[0-9][0-9]:[0-9][0-9]' '$0~/mounted/{print s,$0}{s=RT}' RT_file
Sun Jan  2 07:42:56  2000
Database mounted in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
abc Jan  2 12:42:56  2000
Database mounted in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
Sun Jan  2 23:00:00  2009
Database mounted in Exclusive Mode
Completed: ALTER DATABASE   MOUNT
RS:The input record separator, by default a newline.
RT:The record terminator.  Gawk sets RT to the input text that matched the character or regular expression specified by RS.
[root@mip blog]# awk -v RS='[[:alpha:]]+ [[:alpha:]]+  [0-9] [0-9][0-9]:[0-9][0-9]:[0-9][0-9]' '$0~/mounted/{print RT}' RT_file
Sun Jan  2 07:42:56
Sun Jan  2 23:00:00
[root@mip blog]# awk -v RS='[[:alpha:]]+ [[:alpha:]]+  [0-9] [0-9][0-9]:[0-9][0-9]:[0-9][0-9]' '$0~/mounted/{print s}{s=RT}' RT_file
Sun Jan  2 07:42:56
abc Jan  2 12:42:56
Sun Jan  2 23:00:00
所以你大概也看到了RT的用法呢就是{print s}{s=RT},而不能直接{print RT}


本文来自ChinaUnix博客，如果查看原文请点：http://blog.chinaunix.net/u2/76292/showart_1908459.html

zsszss0000

学习了，好贴子，解释了我对于RT的困惑。顶一个！