diff --git a/lib/spack/spack/environment/shell.py b/lib/spack/spack/environment/shell.py
index 2fb01dbfbf2..80e616c735e 100644
--- a/lib/spack/spack/environment/shell.py
+++ b/lib/spack/spack/environment/shell.py
@@ -67,7 +67,8 @@ def deactivate_header(shell):
         cmds += "set -e SPACK_PROMPT;\n"
         cmds += "functions -e despacktivate;\n"
         #
-        # NOTE: Unsetting SPACK_PROMPT environment variable which is used to avoid changing fish_prompt function.
+        # NOTE: Unsetting SPACK_PROMPT environment variable which is used to
+        # avoid changing fish_prompt function.
         #
     elif shell == "bat":
         # TODO: Color