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
里普雷普
如果您关心性能，请使用与grep语法相似的ripgrep，例如。
rg -C5 "pattern" .
-C、 --context NUM—在每次匹配前后显示NUM行。
还有一些参数，如-A/-after上下文和-B/-before上下文。
该工具构建在Rust的正则表达式引擎之上，这使得它对大数据非常有效。
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。
如果您经常搜索代码，AG银搜索器比grep更高效（即更快）。
使用-C选项显示上下文行。
Eg:
ag -C 3 "foo" myFile
line 1
line 2
line 3
line that has "foo"
line 5
line 6
line 7
里普雷普
如果您关心性能，请使用与grep语法相似的ripgrep，例如。
rg -C5 "pattern" .
-C、 --context NUM—在每次匹配前后显示NUM行。
还有一些参数，如-A/-after上下文和-B/-before上下文。
该工具构建在Rust的正则表达式引擎之上，这使得它对大数据非常有效。
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
使用grep
$ grep --help | grep -i context
Context control:
-B, --before-context=NUM print NUM lines of leading context
-A, --after-context=NUM print NUM lines of trailing context
-C, --context=NUM print NUM lines of output context
-NUM same as --context=NUM
