Re: file comparison

If you are doing this a lot with large files, computing a cryptographic hash is the way to go. If, on the other hand you are:

1) Working on Windows
2) Working over network shares
3) Not doing too much

This little snippet I threw together the other day to compare the contents of two shares might help:

my $share = '\\\\someserver\\someshare\\"'
foreach my $file (@file_list)
{
    my $file2 = $share . $file;
    if (-e $file2)
    {
        my @cmp = `fc $file $file2 | findstr /c:"FC:"`;
        if ($cmp[0])
        {
            unless ($cmp[0] =~ /no differences/)
            {
                print "$file:  $cmp[0]";
            }
        }
        else
        {
            print "$file:\n"
        }
    }
    else
    {
        print "$file is missing from $share\n";
    }
}
[download]

Comment on Re: file comparison Download Code

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Re^2: file comparison by Karger78 (Beadle) on Jun 26, 2009 at 19:58 UTC
Thanks for your method. i am doing a file compare on windows. will your snip work even if the file names are different but the size is the same?	[reply]
Re^3: file comparison by ramlight (Friar) on Jun 26, 2009 at 20:13 UTC
Yes. You just have to feed the appropriate file names to the fc command and look at what it gives you back. It so happened that I was comparing two shares to see where they differed, not quite the same as your problem ... but close enough.	[reply]
Re^4: file comparison by Karger78 (Beadle) on Jun 26, 2009 at 20:29 UTC
I decided to do it the md5 way. So how would i accomplish this. I have it reading the directorys assign it to an array. Right now I am just printing the md5 hash from each element in the array. How would I assign each item to the array, and then loop though each array and compare each field? `opendir(DIR, $RemoteSubDirectory); my @rFileCheck = readdir(DIR); closedir(DIR); opendir(DIR, $localCpPath); my @lFileCheck = readdir(DIR); closedir(DIR); my $c1; foreach (@lFileCheck) { print md5_base64($lFileCheck[$c1]); print "\n"; $c1++; } my $c2; foreach (@rFileCheck) { print md5_base64($rFileCheck[$c1]); print "\n"; $c2++; }` [download]	[reply] [d/l]
Re^5: file comparison by ramlight (Friar) on Jun 26, 2009 at 21:00 UTC


Think about Loose Coupling
	PerlMonks