diff --git a/bootstrap.sh b/bootstrap.sh
index 9b39496f7d..34f51c06cb 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -9,10 +9,12 @@
 # Bootstrap script for running ReFrame from source
 #
 
-BLUE='\033[0;34m'
-GREEN='\033[0;32m'
-YELLOW='\033[0;33m'
-NC='\033[0m'
+if [ -t 1 ]; then
+    BLUE='\033[0;34m'
+    GREEN='\033[0;32m'
+    YELLOW='\033[0;33m'
+    NC='\033[0m'
+fi
 
 CMD()
 {