Index: /trunk/ippScripts/scripts/diff_skycell.pl
===================================================================
--- /trunk/ippScripts/scripts/diff_skycell.pl	(revision 26637)
+++ /trunk/ippScripts/scripts/diff_skycell.pl	(revision 26638)
@@ -230,5 +230,5 @@
 
 # Perform subtraction
-unless ($no_op) {
+{
     my $command = "$ppSub $outroot";
     $command .= " -inimage $input";
@@ -263,42 +263,46 @@
     $command .= " -source_id $source_id" if defined $source_id;
 
-    my ( $success, $error_code, $full_buf, $stdout_buf, $stderr_buf ) =
-        run(command => $command, verbose => $verbose);
-    unless ($success) {
-        $error_code = (($error_code >> 8) or $PS_EXIT_PROG_ERROR);
-        &my_die("Unable to perform ppSub: $error_code", $diff_id, $skycell_id, $error_code);
-    }
-
-    my $outputStatsReal = $ipprc->file_resolve($outputStats);
-    &my_die("Couldn't find expected output file: $outputStats", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless -f $outputStatsReal;
-
-    # measure chip stats
-    $command = "$ppStatsFromMetadata $outputStatsReal - DIFF_SKYCELL";
-    ( $success, $error_code, $full_buf, $stdout_buf, $stderr_buf ) =
-        run(command => $command, verbose => $verbose);
-    unless ($success) {
-        $error_code = (($error_code >> 8) or $PS_EXIT_PROG_ERROR);
-        &my_die("Unable to perform ppStatsFromMetadata: $error_code", $diff_id, $skycell_id, $error_code);
-    }
-    foreach my $line (@$stdout_buf) {
-        $cmdflags .= " $line";
-    }
-    chomp $cmdflags;
-
-    my ($quality) = $cmdflags =~ /-quality (\d+)/; # Quality flag
-
-    if (!$quality) {
-        &my_die("Couldn't find expected output file: $outputName", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputName);
-        &my_die("Couldn't find expected output file: $outputMask", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputMask);
-        &my_die("Couldn't find expected output file: $outputVariance", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputVariance);
-        &my_die("Couldn't find expected output file: $outputSources", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputSources);
-        &my_die("Couldn't find expected output file: $jpeg1Name",    $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($jpeg1Name);
-        &my_die("Couldn't find expected output file: $jpeg2Name",    $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($jpeg2Name);
-        if ($inverse) {
-            &my_die("Couldn't find expected output file: $inverseName", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseName);
-            &my_die("Couldn't find expected output file: $inverseMask", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseMask);
-            &my_die("Couldn't find expected output file: $inverseVariance", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseVariance);
-            &my_die("Couldn't find expected output file: $inverseSources", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseSources);
-        }
+    unless ($no_op) {
+        my ( $success, $error_code, $full_buf, $stdout_buf, $stderr_buf ) =
+            run(command => $command, verbose => $verbose);
+        unless ($success) {
+            $error_code = (($error_code >> 8) or $PS_EXIT_PROG_ERROR);
+            &my_die("Unable to perform ppSub: $error_code", $diff_id, $skycell_id, $error_code);
+        }
+
+        my $outputStatsReal = $ipprc->file_resolve($outputStats);
+        &my_die("Couldn't find expected output file: $outputStats", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless -f $outputStatsReal;
+
+        # measure chip stats
+        $command = "$ppStatsFromMetadata $outputStatsReal - DIFF_SKYCELL";
+        ( $success, $error_code, $full_buf, $stdout_buf, $stderr_buf ) =
+            run(command => $command, verbose => $verbose);
+        unless ($success) {
+            $error_code = (($error_code >> 8) or $PS_EXIT_PROG_ERROR);
+            &my_die("Unable to perform ppStatsFromMetadata: $error_code", $diff_id, $skycell_id, $error_code);
+        }
+        foreach my $line (@$stdout_buf) {
+            $cmdflags .= " $line";
+        }
+        chomp $cmdflags;
+
+        my ($quality) = $cmdflags =~ /-quality (\d+)/; # Quality flag
+
+        if (!$quality) {
+            &my_die("Couldn't find expected output file: $outputName", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputName);
+            &my_die("Couldn't find expected output file: $outputMask", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputMask);
+            &my_die("Couldn't find expected output file: $outputVariance", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputVariance);
+            &my_die("Couldn't find expected output file: $outputSources", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($outputSources);
+            &my_die("Couldn't find expected output file: $jpeg1Name",    $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($jpeg1Name);
+            &my_die("Couldn't find expected output file: $jpeg2Name",    $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($jpeg2Name);
+            if ($inverse) {
+                &my_die("Couldn't find expected output file: $inverseName", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseName);
+                &my_die("Couldn't find expected output file: $inverseMask", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseMask);
+                &my_die("Couldn't find expected output file: $inverseVariance", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseVariance);
+                &my_die("Couldn't find expected output file: $inverseSources", $diff_id, $skycell_id, $PS_EXIT_SYS_ERROR) unless $ipprc->file_exists($inverseSources);
+            }
+        }
+    } else {
+        print "Not executing: $command\n";
     }
 }