perl and the mode element of stat

[eric stewart]

Does anyone know how to take the mode element and convert it to the same information as is in the ls command?
Here is ls:
>ls -l
total 8
drwxr-xr-x 2 estewar1 users 96 Dec 6 15:55 eric
-rw-r--r-- 1 estewar1 users 949 Oct 16 13:08 home_monitor
-rw-r--r-- 1 estewar1 users 38 Oct 16 13:08 lpl
-rw-r--r-- 1 estewar1 users 26 Oct 16 13:08 lpp
-rwxr-xr-x 1 estewar1 users 874 Dec 6 15:43 sam.k

Here is the output from my perl program:
>./sam.k
33261 1 estewar1 users 336 Sep 16 13:09 .eric.df
16877 2 estewar1 users 96 Nov 06 15:55 eric
33188 1 estewar1 users 949 Sep 16 13:08 home_monitor
33188 1 estewar1 users 38 Sep 16 13:08 lpl
33188 1 estewar1 users 26 Sep 16 13:08 lpp
33261 1 estewar1 users 874 Nov 06 15:43 sam.k
TIA
From a beginner of perl!

[Leslie Chaim]

Eric,

The mode returned from the stat function includes the file permissions AND the type. Therefore, you have to mask it.

The following one liner illustrates this:

perl -le 'printf STDOUT "perms are %04o\n", (stat ("$filename"))[2] & 07777'

Hope this helps

Leslie

[Gregory Fruth]

The module Stat::lsMode (available at CPAN) does the conversion
you want. See http://www.perl.com/CPAN-local/README.html.
From the documentation:

use Stat::lsMode;
$file = "somefile.foo";
$mode = (stat $file)[2];
$permissions = format_mode($mode);
# $permissions is now something like `drwxr-xr-x'

$permissions = file_mode($file); # Same as above

If you don't want to install Stat:lsMode, you can also use the
POSIX module (already included in the Perl core module
set) to get the constants you need and build the string yourself:

use POSIX;

$s = (stat("somefile.foo"))[2];

$type = "b" if (S_ISBLK($s));
$type = "c" if (S_ISCHR($s));
$type = "d" if (S_ISDIR($s));
$type = "p" if (S_ISFIFO($s));
$type = "-" if (S_ISREG($s));
# note: "use POSIX" doesn't seem to provide constants for types
# "n" "s" or "l"
# note: if the file is a symlink (type "l"), you might
# want to use lstat() instead of stat()

@modes = qw(- - - - - - - - -);
$modes[0] = "r" if ($s & S_IRUSR);
$modes[1] = "w" if ($s & S_IWUSR);
$modes[2] = "x" if ($s & S_IXUSR);
$modes[3] = "r" if ($s & S_IRGRP);
$modes[4] = "w" if ($s & S_IWGRP);
$modes[5] = "x" if ($s & S_IXGRP);
$modes[6] = "r" if ($s & S_IROTH);
$modes[7] = "w" if ($s & S_IWOTH);
$modes[8] = "x" if ($s & S_IXOTH);
# note: "use POSIX" doesn't seem to provide the constant for
# S_ISVTX (the so-called "sticky" bit)

if ($s & S_ISUID) {$modes[2] = ($s & S_IXUSR) ? "s" : "S";}
if ($s & S_ISGID) {$modes[5] = ($s & S_IXGRP) ? "s" : "S";}

print $type . join("", @modes) . "somefile.foo\n";
print `ls -l somefile.foo`;