linux 中awk用法
awk 用法
awk '条件类型１ ｛动作１｝ 条件类型２ ｛动作2｝ ...' filename
awk内置变量
FS :输入域分隔符，默认为一个空格或tab NR:目前 awk处理的是第几行数据 NF: 每一行拥有的字段数目 $0：代表当前行。 $1,$2,$3...代表被分隔后的各字段
例子: 打印$2,$3中间用" %% "分隔符
vigar@vigar-laptop:~$ ifconfig | grep "inet addr" inet addr:127.0.0.1 Mask:255.0.0.0 inet addr:192.168.0.100 Bcast:192.168.0.255 Mask:255.255.255.0 vigar@vigar-laptop:~$ ifconfig | grep "inet addr" | awk '{print $2 " %% " $3}' addr:127.0.0.1 %% Mask:255.0.0.0 addr:192.168.0.100 %% Bcast:192.168.0.255
区别NR与NＦ的意义
vigar@vigar-laptop:~$ last -n 5 vigar pts/0 :0.0 Tue Sep 18 23:36 still logged in vigar tty7 :0 Tue Sep 18 23:23 still logged in reboot system boot 2.6.32-21-generi Tue Sep 18 23:22 - 23:53 (00:31) vigar pts/1 :0.0 Mon Sep 17 21:31 - down (02:00) vigar tty1 Mon Sep 17 21:11 - down (02:21) wtmp begins Sat Sep 1 15:35:42 2012 vigar@vigar-laptop:~$ last -n 5 | awk '{print $1 "\t lines: " NR "\t columns: " NF}' vigar lines: 1 columns: 10 vigar lines: 2 columns: 10 reboot lines: 3 columns: 11 vigar lines: 4 columns: 10 vigar lines: 5 columns: 9 lines: 6 columns: 0 wtmp lines: 7 columns: 7
从/etc/passwd中找出第三列小于10的数据
vigar@vigar-laptop:~$ cat /etc/passwd | awk '{FS=":"} $3<10 {print $1 "\t" $3}' root:x:0:0:root:/root:/bin/bash daemon 1 bin 2 sys 3 sync 4 games 5 man 6 lp 7 mail 8 news 9
其中有问题，第一行的数据未正常显示，因为第一行时ＦＳ变量尚未被正常设置，这时要用begin
vigar@vigar-laptop:~$ cat /etc/passwd | awk 'BEGIN {FS=":"} $3<10 {print $1 "\t" $3}' root 0 daemon 1 bin 2 sys 3 sync 4 games 5 man 6 lp 7 mail 8 news 9
用一段awk脚本完成工资总数统计，呵呵，熟悉的情况下这比excel还快咧。。。
vigar@vigar-laptop:~$ cat pay.txt name 1st 2nd 3th johnny 23 23 34 perry 24 24 25 sherman 33 33 35 vigar@vigar-laptop:~$ cat pay.txt | awk 'NR==1 {printf "%10s %10s %10s %10s %10s\n",$1,$2,$3,$4,"Total"} NR>=2 {total=$2+$3+$4; printf "%10s %10d %10d %10d %10.2f\n",$1,$2,$3,$4,total}' name 1st 2nd 3th Total johnny 23 23 34 80.00 perry 24 24 25 73.00 sherman 33 33 35 101.00 vigar@vigar-laptop:~$
test-/opt/CC/hello/bin> ps -aux | awk '$4>0 {print $1 "\t" $2 "\t" $4 "\t" $11}' shiadmin 7470 0.1 /usr/NX/bin/nxagent p4admin 12230 15.2 java p4admin 13995 0.2 java shiadmin 17118 1.0 /usr/lib/jvm/jre-1.6.0-openjdk.x86_64/bin/java shiadmin 21822 1.2 /usr/bin/java p4admin 25350 0.5 java p4admin 25965 0.3 java p4admin 27456 1.2 java p4m 28450 0.5 /opt/mqm/bin/amqzmuc0 p4m 28510 0.2 /opt/mqm/bin/amqzlaa0 p4m 29844 0.6 /opt/mqm/bin/amqrmppa