将日志文件的上次修改日期解析为一个变量 [英] Parse a log file's last modified date into a variable

问题描述

我正在尝试将变量设置为自修改日志文件以来的天数.这样，我可以在下次运行命令时将该值用作标志.

I am trying to set a variable to the number of days since a log file was modified. this way I can use that value as a flag for the next time a command runs.

示例:

如果命令昨天运行，则值为1

if the command ran yesterday, the value will be 1

如果命令在5天前运行，则值为5

if the command ran 5 days ago, the value will be 5

我正在寻找解决类似问题的方法，例如:

I'm seeing methods for similar issues such as:

OR %%f IN (%filename%) DO SET filedatetime=%%~tf

或

if (file.exists()) {
  Date lastModified = new Date(file.lastModified());
}

我只是不太了解批处理脚本或Powershell.我愿意在任何一个中运行此脚本.我认为我需要学习的是:

I just don't know batch scripting or powershell very well. I'm open to running this script in either. I think what I need to learn is:

1)从修改日期/时间的命令中提取仅日期的(令牌?)子字符串

1) extract the (tokens?) sub string of just the date from a date/time modified command

2)删除任何冒号或斜杠

2) removing any colons or slashes

3)转换为整数

4)重复今天的日期

一旦我有两个整数，就可以轻松地减去和设置一个变量.

Once I have two integers subtracting and setting a variable should be easy.

有什么建议吗?

推荐答案

在PowerShell中，您可以从另一个日期中减去一个日期并获得一个时间跨度.这样的事情很简单:

In PowerShell you can just subtract one date from another and get a timespan. So something as simple as:

$File = Get-Item C:\Path\To\File.txt
$DaysSinceMod = [datetime]::now - $File.LastWriteTime | Select -Expand Days

然后$DaysSinceMod将是自文件最后一次修改以来的天数.或者，使用一些速记可以简化为:

Then $DaysSinceMod would be how many days since the file was last modified. Or, using some shorthand, that can be reduced to:

$LastMod=(get-date)-(gi C:\Path\To\File.txt)|% Days

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