files and hard-links them to each other to save disk space. Currently it doesn't actually do the hard-linking, it just reports the amount of space saved if it did.
		
			
				
	
	
		
			69 lines
		
	
	
	
		
			1.4 KiB
		
	
	
	
		
			Perl
		
	
	
		
			Executable file
		
	
	
	
	
			
		
		
	
	
			69 lines
		
	
	
	
		
			1.4 KiB
		
	
	
	
		
			Perl
		
	
	
		
			Executable file
		
	
	
	
	
#! /usr/bin/perl -w
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use strict;
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{ my $ofh = select STDOUT;
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  $| = 1;
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  select $ofh;
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}
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#my @paths = ("/nix/store/caef3a49150506d233f474322a824e50-glibc-2.3.3", "/nix/store/a8a9d585d1ad4b1bc911be7743b3b996-glibc-2.3.3");
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my @paths = ("/nix/store");
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my $tmpfile = "/tmp/nix-optimise-hash-list";
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#my $tmpfile = "/data/nix-optimise-hash-list";
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system("find @paths -type f -print0 | xargs -0 md5sum -- > $tmpfile") == 0
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    or die "cannot hash store files";
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system("sort $tmpfile > $tmpfile.sorted") == 0
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    or die "cannot sort list";
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open LIST, "<$tmpfile.sorted" or die;
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my $prevFile;
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my $prevHash;
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my $totalSpace = 0;
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my $savedSpace = 0;
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my $files = 0;
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while (<LIST>) {
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#    print "D";
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    /^([0-9a-f]*)\s+(.*)$/ or die;
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    my $curFile = $2;
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    my $curHash = $1;
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#    print "A";
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    my $fileSize = (stat $curFile)[7];
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#    print "B";
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#    my $fileSize = 1;
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    $totalSpace += $fileSize;
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    if (defined $prevHash && $curHash eq $prevHash) {
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#        print "$curFile = $prevFile\n";
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        $savedSpace += $fileSize;
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    } else {
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        $prevFile = $curFile;
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        $prevHash = $curHash;
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    }
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    print "." if ($files++ % 100 == 0);
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    #print ".";
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#    print "C";
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}
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print "\n";
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print "total space = $totalSpace\n";
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print "saved space = $savedSpace\n";
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my $savings = ($savedSpace / $totalSpace) * 100.0;
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print "savings = $savings %\n";
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close LIST;
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