-osize=$(zpm stat -f '%s' $ZPMDB)
-zpm log -v -i -a 'gc compacting' -t $ZPMDB
-zpm shell $ZPMDB vacuum
-nsize=$(zpm stat -f '%s' $ZPMDB)
-
-printf 'original size %s\n' $osize
-printf 'new size %s\n' $nsize
+if [ $vacuum -ne 0 ]; then
+ osize=$(zpm stat -f '%s' $ZPMDB)
+ zpm shell $ZPMDB vacuum
+ nsize=$(zpm stat -f '%s' $ZPMDB)
+ zpm log -v -i -a 'gc compacted' -t $ZPMDB "$osize -> $nsize"
+
+ printf 'original size %s\n' $osize
+ printf 'new size %s\n' $nsize
+fi