/dev/null is a device file, and can be removed by root, or any user with write access to the /dev directory itself. You can recreate it with 'mknod /dev/null c

/dev/null is a device file, and can be removed by root, or any user with write access to the /dev directory itself. You can recreate it with 'mknod /dev/null c 1 3; chmod 666 /dev/null'. The '1 3' are the major and minor device numbers, respectively, which are assigned / maintained by LANA, the Linux Assigned Numbers Authority.