Update Jenkinsfile

Author: webweb04

Jenkinsfile

@@ -3,6 +3,8 @@ node {
 
     // Make the output directory.
     sh "mkdir -p output"
+    
+    sh "ls -r"
 
     // Write an useful file, which is needed to be archived.
     writeFile file: "output/usefulfile.txt", text: "This file is useful, need to archive it."