ns_show

ns_show comes from the ioctl_ns manual page and is licensed under the GNU General Public License v2 or later.

Example

$ readlink /proc/self/ns/user
user:[4026531837]
$ docker run -ti --rm kinvolk/ns_show /ns_show /proc/self/ns/pid
Device/Inode of owning user namespace is: [0,3] / 4026531837