+# What we use to tag the Docker image. For development and release
+# candidate packages, the OS package has a "~dev" or "~rc" suffix, but
+# Python requires a ".dev" or "rc" suffix. Arvados-cwl-runner will be
+# expecting the Python-compatible version string when it tries to pull
+# the Docker image, but --build-arg is expecting the OS package
+# version.
+cwl_runner_version_tag=$(echo -n $cwl_runner_version | sed s/~dev/.dev/g | sed s/~rc/rc/g)