diff --git a/lib/self-upgrade.bash b/lib/self-upgrade.bash
index df90229..5dd90a7 100755
--- a/lib/self-upgrade.bash
+++ b/lib/self-upgrade.bash
@@ -3,8 +3,10 @@
 # CONSTANTS
 
 #FIXME: source from functions.bash
-readonly DESTINATION=/opt
-readonly MAIN_TAR_GZ_URL="https://git.artcode.re/miaou/miaou-bash/archive/main.tar.gz"
+if [[ ! -v DESTINATION && ! -v MAIN_TAR_GZ_URL ]]; then
+  readonly DESTINATION=/opt
+  readonly MAIN_TAR_GZ_URL="https://git.artcode.re/miaou/miaou-bash/archive/main.tar.gz"
+fi
 
 # FUNCTIONS