$ ID=$(docker export reduce | docker import -)
$ docker tag $ID smaller
$ docker images | grep smaller
smaller  latest  2af3bde3836a  18 minutes ago  6.378 MB
$ mkdir -p /tmp/tmp
$ touch /tmp/tmp/a.log
$ docker run -v /tmp/tmp:/log_dir smaller \
/usr/bin/clean_log 0 
Cleaning logs over 0 days old
$ ls /tmp/tmp/a.log
ls: cannot access /tmp/tmp/a.log: No such file or directory
