linux awk 命令中 next 和 getline

 

001、 continue

[root@PC1 test01]# ls
data
[root@PC1 test01]# cat data         ## 测试数据
1000
naughty 500
cc 400
zoer 100
[root@PC1 test01]# awk '{if(NR == 2) {next}; print $0}' data    ## next相当于外层循环的continue，表示跳过该次迭代
1000
cc 400
zoer 100
[root@PC1 test01]# awk '{if(NR == 2) {printf("")}; print $0}' data    ## 分号后面的print $0是对整个文件起作用的，说明上面的next语句跳过NR == 2
1000
naughty 500
cc 400
zoer 100

 

002、getline

[root@PC1 test01]# ls
a.txt
[root@PC1 test01]# cat a.txt              ## 测试数据
1       Bob     male    28      abc@qq.com      18023394012
2       Alice   female  24      def@gmail.com   18084925203
3       Alice   female  24      def@gmail.com   18084925203
10      Bruce   female  27      bcbd@139.com    13942943905
10      Bruce   female  27      bcbd@139.com    1394294390_002_5
[root@PC1 test01]#  awk '/^1/{print $0; getline; print $0 }' a.txt   ## getline表示跳到下一行，同时具有一次print 的机会
1       Bob     male    28      abc@qq.com      18023394012
2       Alice   female  24      def@gmail.com   18084925203
10      Bruce   female  27      bcbd@139.com    13942943905
10      Bruce   female  27      bcbd@139.com    1394294390_002_5
[root@PC1 test01]#  awk '/^1/{print $0; getline; print "xxx" }' a.txt  ##  没有打印第二个以10开头的行，说明getline跳过了改行
1       Bob     male    28      abc@qq.com      18023394012
xxx
10      Bruce   female  27      bcbd@139.com    13942943905
xxx

 

003、next的情况

[root@PC1 test01]# ls
a.txt
[root@PC1 test01]# cat a.txt                          ## 测试数据
1       Bob     male    28      abc@qq.com      18023394012
2       Alice   female  24      def@gmail.com   18084925203
3       Alice   female  24      def@gmail.com   18084925203
10      Bruce   female  27      bcbd@139.com    13942943905
10      Bruce   female  27      bcbd@139.com    1394294390_002_5
[root@PC1 test01]#  awk '/^1/{print $0; next; print $0 }' a.txt     ## next命令跳过外层循环
1       Bob     male    28      abc@qq.com      18023394012
10      Bruce   female  27      bcbd@139.com    13942943905
10      Bruce   female  27      bcbd@139.com    1394294390_002_5
[root@PC1 test01]#  awk '/^1/{print $0; next; print "xxx" }' a.txt   ## next跳过外层循环，不再执行后面的程序
1       Bob     male    28      abc@qq.com      18023394012
10      Bruce   female  27      bcbd@139.com    13942943905
10      Bruce   female  27      bcbd@139.com    1394294390_002_5

 

004、getline

[root@PC1 test01]# ls
a.txt
[root@PC1 test01]# cat a.txt
1       Bob     male    28      abc@qq.com      18023394012
2       Alice   female  24      def@gmail.com   18084925203
3       Alice   female  24      def@gmail.com   18084925203
4       Alice   female  24      def@gmail.com   18084925203
10      Bruce   female  27      bcbd@139.com    13942943905
10      Bruce   female  27      bcbd@139.com    1394294390_002_5
[root@PC1 test01]#  awk '/^1/{print $0; getline; getline; print $0 }' a.txt   ## 两个getline同时使用，处理匹配行后面的第二行
1       Bob     male    28      abc@qq.com      18023394012
3       Alice   female  24      def@gmail.com   18084925203
10      Bruce   female  27      bcbd@139.com    13942943905
10      Bruce   female  27      bcbd@139.com    1394294390_002_5
[root@PC1 test01]#  awk '/^1/{print $0; getline; getline; print "xxx" }' a.txt
1       Bob     male    28      abc@qq.com      18023394012
xxx
10      Bruce   female  27      bcbd@139.com    13942943905
xxx
[root@PC1 test01]#  awk '/^1/{print $0; getline; getline; print NR, "xxx" }' a.txt   ## 同时输出行号
1       Bob     male    28      abc@qq.com      18023394012
3 xxx
10      Bruce   female  27      bcbd@139.com    13942943905
6 xxx

 。

 

参考：https://www.likecs.com/show-307069191.html