diff --git a/build/tools/extract_utils.sh b/build/tools/extract_utils.sh
index 6ae2ea2..6788dfc 100755
--- a/build/tools/extract_utils.sh
+++ b/build/tools/extract_utils.sh
@@ -2089,7 +2089,7 @@
         white|*) color=7 ;; # white or invalid color
         esac
     fi
-    tput setaf $color
+    if [ -t 1 ] ; then tput setaf $color; fi
     printf '%s\n' "$*"
-    tput sgr0
+    if [ -t 1 ] ; then tput sgr0; fi
 }