linux grep 日志文件中的最后 N 天

Question

这是日志文件：

first second third at January 01 2024 09:54:19
first second third at January 01 2024 09:54:20
first second third at January 03 2024 09:55:19
first second third at January 04 2024 09:56:19
first second third at January 05 2024 09:58:19
first second third at January 06 2024 10:00:22

我要在文件中找到最近3天（我不是指

grep 'January [4-6] 2024

），这样每当我运行时，我都可以找到最近3天的日志。

目前我知道这只能找到确切的一天：

grep "$(date -d '5day ago' +%B\ %d\ %Y)" file

预期输出：

first second third at January 04 2024 09:56:19
first second third at January 05 2024 09:58:19
first second third at January 06 2024 10:00:22

Answer 1

不确定是否有更简洁的方法，但是这个 liner bash 脚本可以做到这一点。

#!/bin/bash
for i in $(seq $(expr $2 - 1) -1 0); do grep "$(date -d "${i}day ago" +%B\ %d\ %Y)" $1; done

用途：

$ ./dategrep file.txt 3
first second third at January 04 2024 09:56:19
first second third at January 05 2024 09:58:19
first second third at January 06 2024 10:00:22