리눅스 에러 Could not get lock /var/lib/dpkg/lock-frontend - open ~

에러내용:
E: Could not get lock /var/~
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?

해결내용:
$ sudo killall apt apt-get
$ sudo rm /var/lib/apt/lists/lock
$ sudo rm /var/cache/apt/archives/lock
$ sudo rm /var/lib/dpkg/lock*

$ sudo dpkg --configure -a 
$ sudo apt update