diff --git a/compile_migrations.sh b/compile_migrations.sh
index 36ab0c2..7a0a1fe 100755
--- a/compile_migrations.sh
+++ b/compile_migrations.sh
@@ -10,13 +10,13 @@ do
     then
         if [ -z $(find ./sql/migration_$migration_num.sql -newer ./include/migrations/$migration_num.sql.h -print) ]
         then
-            ((migration_num++))
+            migration_num=$((migration_num+1))
             continue
         fi
     fi
     echo "Recompiling migration $migration_num"
     xxd -i sql/migration_$migration_num.sql | sed 's/\([0-9a-f]\)$/\0, 0x00/' > ./include/migrations/$migration_num.sql.h
-    ((migration_num++))
+    migration_num=$((migration_num+1))
 done
 
 cd $PWD;