+ mount --rbind /dev foo
+ mount
+ grep -e /dev -e /foo
+ grep -v /sda
udev on /dev type devtmpfs (rw,nosuid,relatime,size=10240k,nr_inodes=467417,mode=755)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620)
shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime)
udev on /root/foo type devtmpfs (rw,nosuid,relatime,size=10240k,nr_inodes=467417,mode=755)
mqueue on /root/foo/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
devpts on /root/foo/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620)
shm on /root/foo/shm type tmpfs (rw,nosuid,nodev,noexec,relatime)
++ mount
++ awk '{print $3}'
++ sort -r
++ grep /foo
+ umount /root/foo/shm /root/foo/pts /root/foo/mqueue /root/foo
+ mount
+ grep -e /dev -e /foo
+ grep -v /sda
udev on /dev type devtmpfs (rw,nosuid,relatime,size=10240k,nr_inodes=467417,mode=755)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620)
shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime)