# mount -t aufs -o dirs=/dev/shm:/mnt=ro none /mnt # ls -la /mnt total 4 drwxrwxrwt 3 root root 80 2009-10-11 17:31 . drwxr-xr-x 22 root root 4096 2009-10-11 14:06 .. -rw-r--r-- 1 root root 0 2009-10-11 17:25 muh # echo "a" > /mnt/muh # echo "b" > /mnt/muh2 # ls -la /mnt/ total 12 drwxrwxrwt 3 root root 120 2009-10-11 17:31 . drwxr-xr-x 22 root root 4096 2009-10-11 14:06 .. -rw-r--r-- 1 root root 2 2009-10-11 17:31 muh -rw-r--r-- 1 root root 2 2009-10-11 17:31 muh2 # umount /mnt # ls -la /mnt/ total 8 drwxr-xr-x 2 root root 4096 2009-10-11 17:25 . drwxr-xr-x 22 root root 4096 2009-10-11 14:06 .. -rw-r--r-- 1 root root 0 2009-10-11 17:25 muh