Run command prompt reason of file locking:
Some instructions in order to prevent the Linux system is interrupted during operation, the lock mechanism is set so that when some instructions, such as instructions run apt like automatically at a specified position (once you run apt or apt-get command, file locking will be created in /var/lib/apt/lists/, /var/lib/dpkg/, /var/cache/apt/archives/ in.) to generate the corresponding file, when the instructions are executed, the file will be automatically deleted