diff --git a/python/CMakeLists.txt b/python/CMakeLists.txt
index e13103839..e908d4671 100644
--- a/python/CMakeLists.txt
+++ b/python/CMakeLists.txt
@@ -266,7 +266,7 @@ endif()
 # Add custom target so we can install with `make python-install`
 set(GTSAM_PYTHON_INSTALL_TARGET python-install)
 add_custom_target(${GTSAM_PYTHON_INSTALL_TARGET}
-        COMMAND ${PYTHON_EXECUTABLE} -m pip install $(if [ -z "$VIRTUAL_ENV" ]; then echo "--user"; fi) .
+        COMMAND ${PYTHON_EXECUTABLE} -m pip install `if [ -z "$VIRTUAL_ENV" ]; then echo --user; fi` .
         DEPENDS ${GTSAM_PYTHON_DEPENDENCIES}
         WORKING_DIRECTORY ${GTSAM_PYTHON_BUILD_DIRECTORY})