linux - 使用 awk 或 sed 或 cut 过滤文本文件？

Question

我正在努力解决这个问题。

$ cat test.txt  
server1
ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com
Search
ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
Web
ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
Web
ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
server2
ec2-xx.xx-xx-xx.us-west-2.compute.amazonaws.com
loaddb
ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
ec2dd
ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
server2
ec2-xx.xx-xx-xx.us-west-2.compute.amazonaws.com
loaddb
ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com

我需要这样的输出:

$ cat test.txt
server1:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
Search:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
Web:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
Web:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
server2:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
loaddb:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
ec2dd:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
server2:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com  
loaddb:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com

Answer 1

使用sed:

$ sed 'N;s/\n/:/' test.txt
server1:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com
Search:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
Web:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
Web:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
server2:ec2-xx.xx-xx-xx.us-west-2.compute.amazonaws.com
loaddb:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
ec2dd:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
server2:ec2-xx.xx-xx-xx.us-west-2.compute.amazonaws.com
loaddb:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com 

此方法使用两个 sed 命令:

• N 从文件中读取第二行并将其附加到模式空间。这样，模式空间中总是有两条连续的线。

• s/\n/:/ 删除模式空间中两行之间的换行符，并将其替换为冒号。

使用awk:

$ awk 'NR%2==1{name=$1;next} {print name ":" $0;}' test.txt
server1:ec2-xx.xx.xx.xxus-west-2.compute.amazonaws.com
Search:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
Web:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
Web:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
server2:ec2-xx.xx-xx-xx.us-west-2.compute.amazonaws.com
loaddb:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
ec2dd:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com
server2:ec2-xx.xx-xx-xx.us-west-2.compute.amazonaws.com
loaddb:ec2-xx-xx-xx-xx.us-west-2.compute.amazonaws.com 

注意事项:

• NR%2==1{name=$1;next}

  这会读取第一行和所有后续的 奇数 行，并将第一个字段分配给变量 name。然后它会跳过其余的命令并跳转到 next 行重新开始。

• 打印名称“:”$0

  在偶数行，这将打印名称、冒号和当前行。

使用纯shell

while read name; read line
do
        printf "%s:%s\n" "$name" "$line"
done <test.txt

这里，一行从 text.txt 读入变量 name，下一行读入变量 line。然后在这两者之间打印一个冒号。