189 8069 5689
无意中感觉磁盘空间不够用，于是使用df -a命令查看，结果令人大吃一惊，全是docker干的好事，在/var/lib/docker/aufs里生成了一堆垃圾：
davidhopper@davidhopper-ThinkPad-P50s:~$ df -a 文件系统 1K-块 已用 可用 已用% 挂载点 sysfs 0 0 0 - /sys proc 0 0 0 - /proc udev 8112832 0 8112832 0% /dev devpts 0 0 0 - /dev/pts tmpfs 1627828 9580 1618248 1% /run /dev/sda6 84293120 77948404 2039772 98% / securityfs 0 0 0 - /sys/kernel/security tmpfs 8139124 18040 8121084 1% /dev/shm tmpfs 5120 4 5116 1% /run/lock tmpfs 8139124 0 8139124 0% /sys/fs/cgroup cgroup 0 0 0 - /sys/fs/cgroup/systemd pstore 0 0 0 - /sys/fs/pstore efivarfs 0 0 0 - /sys/firmware/efi/efivars cgroup 0 0 0 - /sys/fs/cgroup/net_cls,net_prio cgroup 0 0 0 - /sys/fs/cgroup/perf_event cgroup 0 0 0 - /sys/fs/cgroup/cpu,cpuacct cgroup 0 0 0 - /sys/fs/cgroup/pids cgroup 0 0 0 - /sys/fs/cgroup/devices cgroup 0 0 0 - /sys/fs/cgroup/cpuset cgroup 0 0 0 - /sys/fs/cgroup/rdma cgroup 0 0 0 - /sys/fs/cgroup/blkio cgroup 0 0 0 - /sys/fs/cgroup/hugetlb cgroup 0 0 0 - /sys/fs/cgroup/freezer cgroup 0 0 0 - /sys/fs/cgroup/memory systemd-1 - - - - /proc/sys/fs/binfmt_misc debugfs 0 0 0 - /sys/kernel/debug mqueue 0 0 0 - /dev/mqueue hugetlbfs 0 0 0 - /dev/hugepages fusectl 0 0 0 - /sys/fs/fuse/connections configfs 0 0 0 - /sys/kernel/config /dev/sda1 262144 33084 229060 13% /boot/efi binfmt_misc 0 0 0 - /proc/sys/fs/binfmt_misc tmpfs 1627828 56 1627772 1% /run/user/1000 gvfsd-fuse 0 0 0 - /run/user/1000/gvfs /dev/sda6 84293120 77948404 2039772 98% /var/lib/docker/aufs