diff --git a/makefile b/makefile
index 110d46e..05bc98c 100644
--- a/makefile
+++ b/makefile
@@ -44,6 +44,8 @@ validate:; $(Q)./bin/authc user validate $(NAME) $(ACTIVATION_KEY)
 get-user:; $(Q)./bin/authc user get $(NAME) $(LOGIN_OPT)
 
 USER_DB ?= /tmp/authd-migration-user-db.txt
+$(USER_DB): ; cat /tmp/usrdb | awk '{ print $$1 "\t" $$2 }' | sort | uniq > $(USER_DB)
+migration-file: $(USER_DB)
 migrate-user:;      ./bin/authc user migrate $(NAME) $(PASSWORD_HASH) $(LOGIN_OPT)
 migrate-all-users:; ./bin/authc migration-script $(USER_DB) $(LOGIN_OPT)