X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fscripts%2Fcrontab.sh;h=64708ba77e3916d53917fb9453301a0682177163;hb=5740d19b557e3ebef620017bbd85bdea22dda28c;hp=99b4a13a6b77abd171c9495eeac3dfdde1af9fbe;hpb=bf8a6aa5782c9b539ac6cf11ee68f20b7d2c83a6;p=helm.git

diff --git a/matita/scripts/crontab.sh b/matita/scripts/crontab.sh
index 99b4a13a6..64708ba77 100644
--- a/matita/scripts/crontab.sh
+++ b/matita/scripts/crontab.sh
@@ -47,7 +47,23 @@ fi
 CUR_TIME=`echo $SQLQTIME$MARK$SQLQGRMARK | $MYSQL`
 OLD_TIME=`echo $SQLQTIME$LASTMARK$SQLQGRMARK | $MYSQL`
 
-((DELTA=$CUR_CENTS-$OLD_CENTS))
+if [ -z "$CUR_TIME" -o -z "$OLD_TIME"]; then
+    cat <<EOT
+
+    Unable to calculate total time amounts:
+    
+      $SQLQTIME$MARK$SQLQGRMARK 
+      
+    or
+
+      $SQLQTIME$LASTMARK$SQLQGRMARK
+      
+    gave an empty result
+    
+EOT
+fi
+
+((DELTA=$CUR_TIME-$OLD_TIME))
 if [ $DELTA -lt 0 ]; then
   PERC=0
 else