diff --git a/generate-programs-index.pl b/generate-programs-index.pl
index d2c0169..ed75494 100755
--- a/generate-programs-index.pl
+++ b/generate-programs-index.pl
@@ -45,16 +45,28 @@ sub process_dir {
 for my $system ("x86_64-linux", "i686-linux") {
     print STDERR "indexing programs for $system...\n";
 
-    my $out = `nix-env -f $nixExprs -qaP \\* --out-path --argstr system $system`;
+    my $out = `nix-env -f $nixExprs -qaP \\* --drv-path --out-path --argstr system $system`;
     die "cannot evaluate Nix expressions for $system" if $? != 0;
 
+    my %packages;
+
     foreach my $line (split "\n", $out) {
-	my ($attrName, $name, $outPath) = split ' ', $line;
+	my ($attrName, $name, $drvPath, $outPath) = split ' ', $line;
 	die unless $attrName && $name && $outPath;
 	next unless defined $narFiles{$outPath};
 	next unless -d $outPath;
-	process_dir($system, $attrName, "$outPath/bin");
-	process_dir($system, $attrName, "$outPath/sbin");
+	my $prev = $packages{$drvPath};
+	# Prefer shorter attribute names.
+	next if defined $prev &&
+	    (length($prev->{attrName}) < length($attrName) ||
+	     (length($prev->{attrName}) == length($attrName) && $prev->{attrName} le $attrName));
+	$packages{$drvPath} = { attrName => $attrName, outPath => $outPath };
+    }
+
+    foreach my $drvPath (keys %packages) {
+	my $pkg = $packages{$drvPath};
+	process_dir($system, $pkg->{attrName}, "$pkg->{outPath}/bin");
+	process_dir($system, $pkg->{attrName}, "$pkg->{outPath}/sbin");
     }
 }