August 2018
Beginner to intermediate
382 pages
7h 14m
Chinese
Content preview from Perl语言入门
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226
｜
第
12
章
$atime
，
$mtime
和
$ctime
三种表示从纪元（
epoch
）算起的秒数的时间戳。在
Unix
与某些其他系统中，
纪元从公元
1970
年世界标准时间的午夜算起。某些文件系统上会有所不同，比
如
ext2
，会禁用
atime
以改善性能。
对符号链接名调用
stat
函数将会返回符号链接指向对象的信息，而非符号链接本身
的信息（除非该链接指向的对象目前无法访问）。若你需要符号链接本身的信息（多
半没用），你可以用
lstat
（它会返回同样顺序、同样意义的内容）来代替
stat
。如
果
lstat
的参数不是符号链接，它会和
stat
一样返回空列表。
就像文件测试操作符一样，
stat
和
lstat
的默认操作数是
$_
。也就是说，底层
的
stat
系统调用会对标量变量
$_
里的文件名进行操作。
模块
File::stat
提供了兼容
stat
且更为友好的操作界面
。
localtime
函数
你能获得的时间戳值（比如从
stat
函数返回的时间戳）看起来通常会像
1454133253
这样的形式。对大多数人来说，这样的数字实在不太方便，除非你想通过减法来比较
两个时间戳大小。所以，你可能需要将它转换成比较容易阅读的形式，比如
Sat Jan
30 00:54:13 2016
这样的字符串。
Perl
可以在标量上下文中使用
localtime
函数完成
这种转换：
my $timestamp = 1454133253;
my $date = localtime ...
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