GETINO(1)                        User Commands                       GETINO(1)

NAME
       getino - print the unique inode number associated to a process file
       descriptor or namespace for a given PID

SYNOPSIS
       getino
       [--pidfs|--cgroupns|--ipcns|--netns|--mntns|--pidns|--timens|--userns|--utsns]
       [--print-pid|-p] PID[:inode]...

       getino [--print-pid|-p] PID[:inode]...

       getino PID[:inode]...

DESCRIPTION
       getino is a simple command that prints the inode numbers associated
       with the process file descriptor (pidfd) or namespace for all PIDs
       passed to it as arguments.

       The kernel guarantees that the inode number associated with a process's
       file descriptor is exempt from reuse during the current boot cycle;
       therefore, a process can be uniquely identified by its PID and the
       inode number, conveniently so with the format 'PID:inode'.  As an
       example, this enables race-free signalling of processes with kill(1),
       which accepts the aforementioned PID format.

       Inode numbers associated with a namespace for a given process are
       essentially namespace IDs, identical to the inode number reported by
       /proc/pid/ns/nstype, see namespaces(7) for more details.

OPTIONS
       -p, --print-pid
           Print both the PID and pidfd/namespace inode separated by a colon
           ':', in respective order.  This format convention can be used to
           address processes in a race-free manner, e.g. for signalling with
           the kill(1) command.

       --pidfs
           Print the unique inode number for a process's pidfs file
           descriptor.

       --cgroupns
           Print the unique cgroup namespace inode number. See
           cgroup_namespaces(7)

       --ipcns
           Print the unique ipc namespace inode number. See ipc_namespaces(7)

       --netns
           Print the unique network namespace inode number. See
           network_namespaces(7)

       --mntns
           Print the unique mount namespace inode number. See
           mount_namespaces(7)

       --pidns
           Print the unique pid namespace inode number. See pid_namespaces(7)

       --timens
           Print the unique time namespace inode number. See
           time_namespaces(7)

       --userns
           Print the unique user namespace inode number. See
           user_namespaces(7)

       --utsns
           Print the unique uts namespace inode number. See uts_namespaces(7)

       -h, --help
           Display help text and exit.

       -V, --version
           Display version and exit.

EXIT STATUS
       getino has the following exit status values:

       0
           success

       1
           unspecified failure

NOTES
       getino requires support for the pidfs pseudo-filesystem (introduced in
       Linux version 6.9), to retrieve a valid inode for a process file
       descriptor.

AUTHORS
       Christian Goeschel Ndjomouo <cgoesc2@wgu.edu>

SEE ALSO
       kill(1) pidfd_open(2) namespaces(7)

REPORTING BUGS
       For bug reports, use the issue tracker
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY
       The getino command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.42                   2026-04-01                         GETINO(1)