使用awk或sed或cut过滤文本文件？

Question

我正在尝试解决此问题。

$ 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，并将其添加到模式空间。 这样，模式空间中始终具有连续的两行。

• s/\\n/:/从模式空间的两行之间删除换行符，并用冒号代替。

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 

笔记：

• NR%2==1{name=$1;next}

  这将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，它跳过其余命令，并跳转到next行重新开始。

• print name ":" $0

  在偶数行上，这将打印名称，冒号和当前行。

使用纯壳

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

在这里，从text.txt中将一行读入变量name然后将另一行读入变量line 。 然后将这两个标记之间用冒号打印。

Answer 2

您可以简单地使用paste命令，

paste -d: - - < file

通过Perl，

perl -pe 's/\n/:/g if $.%2==1' file

$. Perl中的NR与awk中的NR相似。 因此，它仅采用奇数行并将换行符替换为:仅在特定行上。

Answer 3

这个awk可以做到，但是如果您不完全了解getline ，请小心。

awk '{a=$1;getline;print a":"$1}' file
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

这是一种更好的方法：

awk 'ORS=NR%2?":":RS' file
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