我正在尝试从Jenkins管道运行ps命令，如下所示：

stages {
    stage('Check if auto-scale job is running') {
        steps {
            script{
                sh '''#!/bin/bash
                    set -x
                    
                    while [ $(ps -ef | grep -w autoscale_cluster.sh | wc -l) > 1 ]
                    do
                        echo "waiting for auto-scale job to finish..."
                        sleep 2
                    done
                    
                    echo "resuming..."
                '''
            }
        }
    }
}

然而，这是我得到的输出：

ps: not found