grep最后n匹配所有文件 [英] grep Last n Matches Across Files

问题描述

我使用grep在一组文件中提取行：
$ b $ grep somestring * .log

是否可以将每个文件的最大匹配数限制为每个文件的最后n个匹配项？

解决方案

认为grep不支持从文件末尾限制N个匹配，所以这就是你必须做的事情。

  ls * .log |同时阅读fn;做grep -iH创建$ fn|尾巴-1;完成
  

将 tail -1 -1替换为N.（-H选项是打印文件名，否则它将不会被打印，如果你是一个单独的文件grep，那正是我们正在做的）

注意：上面的soln可以很好地处理带有空格的文件名。

从文件开头的N个匹配

  grep -i -m1 create * .log 
  

用N代替 -m1 1。

I'm using grep to extract lines across a set of files:

grep somestring *.log

Is it possible to limit the maximum number of matches per file to the last n matches from each file?

解决方案

Well I think grep does not support to limit N matches from the end of file so this is what you have to do

ls *.log | while read fn; do grep -iH create "$fn" | tail -1; done

Replace tail -1 -1 with N. (-H options is to print the file name else it wont be printed if you are grep in a single file and thats exactly we are doing above)

NOTE: Above soln will work fine with file names with spaces.

For N matches from the start of the file

grep -i -m1 create *.log

Replace -m1 1 with N.

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