ubuntu apt update时Could not get lock /var/lib/apt/lists/lock

Under Linux execution sudo apt-get update prompt an error:
                E: Could not GET Lock / var / lib / APT / Lists / Lock - Open (11 Resource temporarily. It is unavailable Sign of the) 
                E: Unable to Lock at The List Directory
        online search to The solution-"Remove /var/lib/apt/list/lock"-is actually an extreme situation, that is, it is used when the last update was not closed normally.
        In most cases, the cause of the problem is that other programs such as system automatic update, Synaptic, etc. are using the apt-get process. So the solution is to shut down this process.
        The details are as follows:
              1. ps -ef | grep apt-get to see if there is an apt-get process 
              2. sudo killall -9 apt-get forcibly close the corresponding process 
              3. sudo apt-get update; sudo apt-get dist-upgrade to continue upgrading