linux中awk命令中的next的用法

 

1、linux中awk中next命令相当于循环语句中的continue

[root@centos7 test2]# seq 6
1
2
3
4
5
6
[root@centos7 test2]# seq 6 | awk '$0 ~ /5/ {next}; {print $0}'  ## 当前行匹配5的时候，跳过本次循环
1
2
3
4
6

 

2、测试数据

[root@centos7 test2]# ls
a.txt
[root@centos7 test2]# cat a.txt
web01[192.168.2.100]
httpd ok
tomcat ok
sendmail ok
web02[192.168.2.101]
httpd ok
postfix ok
web03[192.168.2.102]
mysqld ok
httpd ok

 

if实现数据折叠：

[root@centos7 test2]# ls
a.txt
[root@centos7 test2]# cat a.txt
web01[192.168.2.100]
httpd ok
tomcat ok
sendmail ok
web02[192.168.2.101]
httpd ok
postfix ok
web03[192.168.2.102]
mysqld ok
httpd ok
[root@centos7 test2]# awk '{if($0 ~ /^web/){title = $0} else {print title, $0}}' a.txt
web01[192.168.2.100] httpd ok
web01[192.168.2.100] tomcat ok
web01[192.168.2.100] sendmail ok
web02[192.168.2.101] httpd ok
web02[192.168.2.101] postfix ok
web03[192.168.2.102] mysqld ok
web03[192.168.2.102] httpd ok                  ## next的作用是跳过本次迭代
[root@centos7 test2]# awk '{if($0 ~ /^web/) {title = $0; next}{print title, $0}}' a.txt
web01[192.168.2.100] httpd ok
web01[192.168.2.100] tomcat ok
web01[192.168.2.100] sendmail ok
web02[192.168.2.101] httpd ok
web02[192.168.2.101] postfix ok
web03[192.168.2.102] mysqld ok
web03[192.168.2.102] httpd ok