我如何在每一条匹配的线周围显示前面和后面的5条线?


当前回答

grep astring myfile -A 5 -B 5

这将grep“myfile”表示“跨步”,并在每次比赛前后显示5行

其他回答

对于BSD或GNUgrep,可以使用-B num设置匹配前的行数,使用-A num设置匹配后的行数。

grep -B 3 -A 2 foo README.txt

如果希望前后行数相同,可以使用-C num。

grep -C 3 foo README.txt

这将显示前3行和后3行。

grep astring myfile -A 5 -B 5

这将grep“myfile”表示“跨步”,并在每次比赛前后显示5行

-A和-B将起作用,-C n(对于n行上下文)或-n(对于n个上下文……只要n是1到9)也会起作用。

让我们用一个例子来理解。我们可以使用带有选项的grep:

-A 5  # this will give you 5 lines after searched string.
-B 5  # this will give you 5 lines before searched string.
-C 5  # this will give you 5 lines before & after searched string

实例File.txt包含6行,以下是操作。

[abc@xyz]~/% cat file.txt # print all file data
this is first line
this is 2nd line
this is 3rd line
this is 4th line
this is 5th line
this is 6th line

[abc@xyz]~% grep "3rd" file.txt # we are searching for keyword '3rd' in the file
this is 3rd line

[abc@xyz]~% grep -A 2 "3rd" file.txt # print 2 lines after finding the searched string
this is 3rd line
this is 4th line
this is 5th line

[abc@xyz]~% grep -B 2 "3rd" file.txt # Print 2 lines before the search string.
this is first line
this is 2nd line
this is 3rd line

[abc@xyz]~% grep -C 2 "3rd" file.txt # print 2 line before and 2 line after the searched string 
this is first line
this is 2nd line
this is 3rd line
this is 4th line
this is 5th line

记住选项的技巧:选项:

-一个 -> 之后的平均值-B级 -> B表示之前。-c类 -> 介于两者之间

我通常使用

grep searchstring file -C n # n for number of lines of context up and down

许多像grep这样的工具也有很棒的man文件。我发现自己经常参考grep的手册页,因为你可以用它做很多事情。

man grep

许多GNU工具也有一个信息页,除了手册页之外,它可能还有更多有用的信息。

info grep