sed/awk删除字符串的第二次出现-与平台无关 [英] Sed/Awk to delete second occurence of string - platform independent
问题描述
我正在寻找bash中可以在linux和OS X上都运行的行，以删除包含所需字符串的第二行:
I'm looking for a line in bash that would work on both linux as well as OS X to remove the second line containing the desired string:
Header
1
2
...
Header
10
11
...
应该成为
Header
1
2
...
10
11
...
我的第一次尝试是使用sed的删除选项:
My first attempt was using the deletion option of sed:
sed -i '/^Header.*/d' file.txt
但是，这也消除了第一次出现的情况.
But well, that removes the first occurence as well.
如何从给定的事件中删除匹配模式建议使用类似这样的内容:
How to delete the matching pattern from given occurrence suggests to use something like this:
sed -i '/^Header.*/{2,$d} file.txt
但是在出现错误的OS X上
But on OS X that gives the error
sed: 1: "/^Header.*/{2,$d}": extra characters at the end of d command
接下来，我尝试了替换，在该处我知道如何使用2,$，并且随后删除了空行:
Next, i tried substitution, where I know how to use 2,$, and subsequent empty line deletion:
sed -i '2,$s/^Header.*//' file.txt
sed -i '/^\s*$/d' file.txt
This works on Linux, but on OS X, as mentioned here sed command with -i option failing on Mac, but works on Linux , you'd have to use
sed -i '' '2,$s/^Header.*//' file.txt
sed -i '' '/^\s*$/d' file.txt
这反过来在Linux上不起作用.
And this one in return doesn't work on Linux.
那么我的问题是，没有一种简单的方法可以在任何Bash中使它起作用吗?不必sed，但应尽可能独立于外壳，并且我需要修改文件本身.
My question then, isn't there a simple way to make this work in any Bash? Doesn't have to be sed, but should be as shell independent as possible and i need to modify the file itself.
推荐答案
由于这是文件相关的，而不是行相关的，因此awk可能是更好的工具.
Since this is file-dependent and not line-dependent, awk can be a better tool.
只需对发生这种情况的次数进行计数:
Just keep a counter on how many times this happened:
awk -v patt="Header" '$0 == patt && ++f==2 {next} 1' file
这将跳过与给定模式完全匹配的行，并第二次执行该操作.在其余的行上，它可以正常打印.
This skips the line that matches exactly the given pattern and does it for the second time. On the rest of lines, it prints normally.
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