--- orig/shell-tools
+++ mod/shell-tools
@@ -47,7 +47,7 @@
     if [ -n "${traps}" ]; then
 	local old_action=$(echo "${traps}" \
 	    | sed --quiet --expression="s/^trap[[:space:]]\+--[[:space:]]\+'\([^']\+\)'[[:space:]]\+${condition}\$/\1/p")
-action="${action}; ${old_action}"
+	action="${action}; ${old_action}"
     fi
     trap "${action}" "${condition}"
 }
