Index: trunk/ippTasks/diff.pro
===================================================================
--- trunk/ippTasks/diff.pro	(revision 14693)
+++ trunk/ippTasks/diff.pro	(revision 16298)
@@ -1,23 +1,10 @@
-### This file contains panTasks definitions for performing the image differencing.
+## diff.pro : image difference analysis : -*- sh -*-
 
-### After a difference (with associated diff_id) is defined, the difference is performed
-### (tasks in diffSkyfile).
+## This file contains panTasks definitions for performing the image differencing.
+## After a difference (with associated diff_id) is defined, the difference is performed
+## (tasks in diffSkyfile).
 
-
-### Setups
-if ($?network == 0)
-  $network = 1
-end
-if ($?parallel == 0)
-  $parallel = 0
-end
-if ($?VERBOSE == 0)
-  echo "VERBOSE not defined: load pantasks.pro first"
-  break
-end
-if ($?LOGDIR == 0)
-  echo "LOGDIR not defined: load pantasks.pro first"
-  break
-end
+# test for required global variables
+check.globals
 
 $LOGSUBDIR = $LOGDIR/diff
@@ -66,6 +53,6 @@
   host         local
 
-  periods      -poll $loadpoll
-  periods      -exec $loadexec
+  periods      -poll $LOADPOLL
+  periods      -exec $LOADEXEC
   periods      -timeout 30
   npending     1
@@ -120,5 +107,5 @@
     book npages diffSkyfile -var N
     if ($N == 0) break
-    if ($network == 0) break
+    if ($NETWORK == 0) break
     
     # look for new images in diffSkyfile (pantaskState == INIT)
@@ -133,5 +120,5 @@
     # specify choice of remote host
     # XXX need to choose based on diffs
-    if ($parallel)
+    if ($PARALLEL)
       host anyhost
     else