使用 Bash 获取特定文件的 mtime？
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Get mtime of specific file using Bash?
提问by Industrial
I am well aware of being able to do find myfile.txt -mtime +5to check if my file is older than 5 days or not. However I would like to fetch mtime in days of myfile.txt and store it into a variable for further usage. How would I do that?
我很清楚能够find myfile.txt -mtime +5检查我的文件是否超过 5 天。但是，我想以 myfile.txt 的天数获取 mtime 并将其存储到变量中以供进一步使用。我该怎么做？
回答by T.J. Crowder
statcan give you that info:
stat可以给你这些信息：
filemtime=`stat -c %Y myfile.txt`
%Ygives you the last modification as "seconds since The Epoch", but there are lots of other options; more info. So if the file was modified on 2011-01-22 at 15:30 GMT, the above would return a number in the region of 1295710237.
%Y为您提供“自大纪元以来的秒数”的最后修改，但还有很多其他选项；更多信息。因此，如果文件在 2011 年 1 月 22 日格林威治标准时间 15:30 被修改，则上述内容将返回 1295710237 区域内的数字。
Edit: Ah, you want the time in days since it was modified. That's going to be more complicated, not least because a "day" is not a fixed period of time (some "days" have only 23 hours, others 25 — thanks to daylight savings time).
编辑：啊，您想要自修改以来的天数。这将变得更加复杂，尤其是因为“一天”不是固定的时间段（有些“天”只有 23 小时，有些则有 25 小时——这要归功于夏令时）。
The naiveversion might look like this:
在天真的版本可能是这样的：
filemtime=`stat -c %Y `
currtime=`date +%s`
diff=$(( (currtime - filemtime) / 86400 ))
echo $diff
...but again, that's assuming a day is always exactly 86,400 second long.
...但同样，这是假设一天总是正好 86,400 秒长。
More about arithmetic in bash here.
更多关于 bash 中的算术在这里。
回答by mob
AGE=$(perl -e 'print -M $ARGV[0]' $file)
will set $AGE to the age of $file in days, as Perl's -Moperator handles the statcall and the conversion to days for you.
将 $AGE 设置为 $file 的天数，因为 Perl 的-M操作员会stat为您处理调用和转换为天。
The return value is a floating-point value (e.g., 6.62849537 days). Add an intto the expression if you need to have an integer result
返回值是一个浮点值（例如，6.62849537 天）。int如果需要整数结果，请在表达式中添加一个
AGE=$(perl -e 'print int -M $ARGV[0]' $file)
Ruby and Python also have their one-liners to stat a file and return some data, but I believe Perl has the most concise way.
Ruby 和 Python 也有它们的单行程序来统计文件并返回一些数据，但我相信 Perl 有最简洁的方式。
回答by silvio
I this the answer?
我这是答案？
A=$(stat -c "%y" myfile.txt)
look at stat-help
看看统计帮助
stat --help
Usage: stat [OPTION]... FILE...
Display file or file system status.
[...]
-c --format=FORMAT use the specified FORMAT instead of the default;
output a newline after each use of FORMAT
[...]
The valid format sequences for files
[...]
%y Time of last modification, human-readable
%Y Time of last modification, seconds since Epoch
[...]
