Question

我已经在Combining two sed commands，https://unix.stackexchange.com/questions/407937/combine-two-sed-commands，combine two sed commands和其他问题中进行了阅读，但是仍然不知道如何组合两个sed命令。

这是我的示例文件（file.txt）。

    10/8/18
6:54:42.000 PM  
Oct  8 19:54:42 x.x.x.x 231 <134> 2018-10-08T18:54:42Z  Server_Name: 2018-10-08 18:54:42 - Server_Name - [127.0.0.1] System()[] - User Accounts modified. Removed username JohnDoe from authentication server RSA.

    host =  Server_Name 
    source =    /opt/x.x.x.x-20181008.log   
    sourcetype =    sslvpn  

    10/8/18
6:47:33.000 PM  
Oct  8 19:47:33 x.x.x.x 266 <134> 2018-10-08T18:47:33Z  Server_Name: 2018-10-08 18:47:33 - Server_Name - [y.y.y.y] JohnDoe - Closed connection to z.z.z.z after 6547 seconds, with 5526448 bytes read and 15634007 bytes written 

    host =  Server_Name 
    source =    /opt/x.x.x.x-20181008.log   
    sourcetype =    sslvpn  

    10/8/18
6:47:33.000 PM  
Oct  8 19:47:33 x.x.x.x 229 <134> 2018-10-08T18:47:33Z  Server_Name: 2018-10-08 18:47:33 - Server_Name - [y.y.y.y] JohnDoe - VPN Tunneling: Session ended for user with IPv4 address z.z.z.z

    host =  Server_Name 
    source =    /opt/x.x.x.x-20181008.log   
    sourcetype =    sslvpn  

    10/8/18
6:47:33.000 PM  
Oct  8 19:47:33 x.x.x.x 204 <134> 2018-10-08T18:47:33Z  Server_Name: 2018-10-08 18:47:33 - Server_Name - [y.y.y.y] JohnDoe - Logout from y.y.y.y (session:abc)

    host =  Server_Name 
    source =    /opt/x.x.x.x-20181008.log   
    sourcetype =    sslvpn

所需的输出

Oct  8 19:54:42 x.x.x.x 231 <134> 2018-10-08T18:54:42Z  Server_Name: 2018-10-08 18:54:42 - Server_Name - [127.0.0.1] System()[] - User Accounts modified. Removed username JohnDoe from authe
ntication server RSA.

Oct  8 19:47:33 x.x.x.x 266 <134> 2018-10-08T18:47:33Z  Server_Name: 2018-10-08 18:47:33 - Server_Name - [y.y.y.y] JohnDoe - Closed connection to z.z.z.z after 6547 seconds, with 5526448 by
tes read and 15634007 bytes written

Oct  8 19:47:33 x.x.x.x 229 <134> 2018-10-08T18:47:33Z  Server_Name: 2018-10-08 18:47:33 - Server_Name - [y.y.y.y] JohnDoe - VPN Tunneling: Session ended for user with IPv4 address z.z.z.z

Oct  8 19:47:33 x.x.x.x 204 <134> 2018-10-08T18:47:33Z  Server_Name: 2018-10-08 18:47:33 - Server_Name - [y.y.y.y] JohnDoe - Logout from y.y.y.y (session:abc)

我所做的（2条sed命令）产生输出的是

sed -n '/[0-9]\/[0-9]\//,+1!p' file.txt > file2.txt
sed -n '/host =/,+3!p' file2.txt

基于其他问题的答案，半冒号是解决方案，但我只是不确定如何使用它。这是我尝试使用完全无效的半冒号。

sed -n '/[0-9]\/[0-9]\//,+1!p;/host =/,+3!p' file.txt

请告知

Answer 1

为什么不修改sed使其仅匹配模式并删除而不定义否定条件？只需使用d运算符

删除行

sed -e '/[0-9]\/[0-9]\//,+1d' -e '/host =/,+3d' file

我猜想您尝试使用-n标志可能是无法将两个构造结合在一起的可能原因。因为根据定义，-n标志将使sed仅打印匹配的部分，而不打印其他所有行。

Answer 2

您已得到问题的答案，但使用的工具错误。除了指定2个不同的否定条件（例如测试不需要的输出而不是执行的操作）以外，还有很多更好的方法可以执行所需的操作。例如：

grep -A 1 --no-group-separator '^[[:alpha:]]' file

awk '(NR%8) ~ /^[34]$/' file

awk '/^[[:alpha:]]/{c=2} c&&c--' file

或者如果您真的觉得需要使用sed：

sed -n '/^[[:alpha:]]/,/^/p' file

通常-避免使用负逻辑，因为它比正逻辑更难于理解（并且通常很难维护），并且会带来双重负逻辑的风险，这非常容易混淆且容易出错。

如何结合两个sed命令？

2 个答案: