How to extract the column data from multidimensional array in perl

Question

ls -l

-rw-r--r-- 1 angus angus    0 2013-08-16 01:33 copy.pl
-rw-r--r-- 1 angus angus 1931 2013-08-16 08:27 copy.txt
-rw-r--r-- 1 angus angus  492 2013-08-16 03:15 ex.txt
-rw-r--r-- 1 angus angus   25 2013-08-16 09:07 hello.txt
-rw-r--r-- 1 angus angus   98 2013-08-16 09:05 hi.txt

I need only the read, write , access data as well as the file name.

#! /usr/bin/perl -w
@list = `ls -l`;
$index = 0;
#print "@list\n";
for(@list){
 ($access) = split(/[\s+]/,$_);
 print "$access\n";
 ($data) = split(/pl+/,$_);
 print "$data";
 @array1 = ($data,$access);
}
print "@array1\n"

I have written this code to extract the read,write,access permission details and the file name corresponding to it. I couldn't extract the filename which is the last column.

mpapec · Accepted Answer · 2013-08-17 07:12:51Z

7

Check perl stat http://perldoc.perl.org/functions/stat.html It's more robust and efficient than calling external ls command,

use File::stat;
$sb = stat($filename);
printf "File is %s, size is %s, perm %04o, mtime %s\n",
       $filename, $sb->size, $sb->mode & 07777,
       scalar localtime $sb->mtime;

answered Aug 17, 2013 at 7:12

mpapec

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Comments

edi_allen · Accepted Answer · 2013-08-17 19:30:55Z

2

I think you have an error in line number 8 of your script. You are trying to split the line using the string "pl" as a delimiter which will only match the first line of your input and will not give you what I think you want.

I believe you should just split the whole line on white space and assign just the columns you want (number 1 and 8 in this case).

change your loop for this:

for my $filename (@list){
    chomp($filename);
    my ($access, $data) = (split(/\s+/, $filename))[0, 7]; #use a slice to get only the columns you want.
    print "$access $data\n";
}

Note: mpapec suggestion to use Stat would be better. I just wanted to let you know why your code is not working.

edited Aug 17, 2013 at 19:30

answered Aug 17, 2013 at 18:56

edi_allen

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