diff --git a/require-ess/tools/iocsh_utils.py b/require-ess/tools/iocsh_utils.py
index e94d76333f0f1d4b4b153edc35e7a8ca0dac3cae..c92c17e13ad39c00f8ee2434d832f6d09cacbe3c 100755
--- a/require-ess/tools/iocsh_utils.py
+++ b/require-ess/tools/iocsh_utils.py
@@ -12,7 +12,7 @@ from pathlib import Path
 @atexit.register
 def graceful_shutdown() -> None:
     print("\nExiting e3 IOC shell")
-    os.system("[[ $- == *i* ]] && stty sane")
+    os.system("[[ -t 1 ]] && stty sane")
 
 
 class TemporaryStartupScript: