如何查找文件是否可供所有人阅读？

Question

如何查找UNIX中的每个人是否可以读取文件？

Answer 1

(相对)现代解决方案:使用File :: stat,一个自5.004以来的核心模块,以及Fcntl,它一直在Perl 5.参见perldoc -f stat.

use strict;
use warnings;
use File::stat;
use Fcntl qw(:mode);

...

my $mode = stat($filename)->mode;
my $allCanRead = ($mode & S_IRUSR)   # User can read
              && ($mode & S_IRGRP)   # Group can read
              && ($mode & S_IROTH);  # Others can read

Answer 2

来自perldoc:

$mode = (stat($filename))[2];
printf "Permissions are %04o\n", $mode & 07777;

要提取其他读取位,您可以这样做

print "read for everyone" if $mode & 4;    # pick bit 2 from mode