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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | NOTES | AUTHORS | SEE ALSO | REPORTING BUGS | AVAILABILITY |
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GETINO(1) User Commands GETINO(1)
getino - print the unique inode number associated to a process
file descriptor or namespace for a given PID
getino
[--pidfs|--cgroupns|--ipcns|--netns|--mntns|--pidns|--timens|--userns|--utsns]
[--print-pid|-p] PID[:inode]...
getino [--print-pid|-p] PID[:inode]...
getino PID[:inode]...
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 for the current
boot cycle; therefore, a process can be uniquely identified by its
PID and the inode number, conveniently so in the format
'PID:inode'. As an example, this enables race-free process
signalling with the kill(1) command, which accepts addressing
processes with the aforementioned 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.
-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.
getino has the following exit status values:
0
success
1
unspecified failure
getino requires support for the pidfs pseudo-filesystem,
introduced in the Linux kernel version 6.9, to retrieve a valid
inode for process file descriptor.
Christian Goeschel Ndjomouo <cgoesc2@wgu.edu>
kill(1) pidfd_open(2) namespaces(7)
For bug reports, use the issue tracker
<https://github.com/util-linux/util-linux/issues>.
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/>. This page is
part of the util-linux (a random collection of Linux utilities)
project. Information about the project can be found at
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
bug report for this manual page, send it to
util-linux@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2026-01-16. (At that time, the date of the most recent commit that
was found in the repository was 2026-01-14.) If you discover any
rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to man-pages@man7.org
util-linux 2.42-start-1196-9... 2026-01-15 GETINO(1)
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HTML rendering created 2026-01-16 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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