diff --git a/src/aedifix/templates/variables.mk.in b/src/aedifix/templates/variables.mk.in
index 8d5bf4b..edc1543 100644
--- a/src/aedifix/templates/variables.mk.in
+++ b/src/aedifix/templates/variables.mk.in
@@ -3,7 +3,7 @@
 # subsequent calls to configure (or reconfigure) will overwrite any changes.
 .NOTPARALLEL:
 
-export SHELL ?= /usr/bin/env bash
+export SHELL = /usr/bin/env bash
 export AWK ?= awk
 export PYTHON ?= @AEDIFIX_PYTHON_EXECUTABLE@
 export CMAKE ?= @CMAKE_COMMAND@