diff --git a/Jenkinsfile-dataset-stats b/Jenkinsfile-dataset-stats
index b55c1ae..a76b960 100644
--- a/Jenkinsfile-dataset-stats
+++ b/Jenkinsfile-dataset-stats
@@ -30,7 +30,8 @@ pipeline {
         }
         stage('Archive file') {
             steps {
-                sh "docker cp $$(docker ps -aq -f status=exited -f ancestor=nbrt10/ium:v1 | head -n 1):/app/output.txt ${env.WORKSPACE}"
+                def containerId = sh(script: "docker ps -aq -f status=exited -f ancestor=nbrt10/ium:v1 | head -n 1", returnStdout: true).trim()
+                sh "docker cp ${containerId}:/app/output.txt ${env.WORKSPACE}"
                 archiveArtifacts artifacts: 'output.txt', fingerprint: true
             }
         }