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LSNS(8) System Administration LSNS(8)

NAME

lsns - list namespaces

SYNOPSIS

lsns [options] [namespace]

DESCRIPTION

lsns lists information about all the currently accessible namespaces or about the given namespace. The namespace identifier is an inode number.

The default output is subject to change. So whenever possible, you should avoid using default outputs in your scripts. Always explicitly define expected output mode (--tree or --list) and columns by using the --output option together with a columns list in environments where a stable output is required.

The NSFS column, printed when net is specified for the --type option, is special; it uses multi-line cells. Use the option --nowrap to switch to ","-separated single-line representation.

Note that lsns reads information directly from the /proc filesystem and for non-root users it may return incomplete information. The current /proc filesystem may be unshared and affected by a PID namespace (see unshare --mount-proc for more details). lsns is not able to see persistent namespaces without processes where the namespace instance is held by a bind mount to /proc/pid/ns/type.

OPTIONS

-H, --list-columns

List the available columns, use with --json or --raw to get output in machine-readable format.

-J, --json

Use JSON output format.

-l, --list

Use list output format.

-n, --noheadings

Do not print a header line.

-o, --output list

Specify which output columns to print. Use --help to get a list of all supported columns.

The default list of columns may be extended if list is specified in the format +list (e.g., lsns -o +PATH).

--output-all

Output all available columns.

-P, --persistent

Display only the namespaces without processes (aka persistent namespaces), created by bind mounting /proc/pid/ns/type files to a filesystem path.

-p, --task PID

Display only the namespaces held by the process with this PID.

-Q, --filter expr

Print only the namespaces that meet the conditions specified by the expr.

This feature is EXPERIMENTAL. See also scols-filter(5). For example exclude root as username, but print every namespaces more than one process belongs to:

lsns --filter 'USER != "root" and NPROCS > 1'

-r, --raw

Use the raw output format.

-t, --type type

Display the specified type of namespaces only. The supported types are mnt, net, ipc, user, pid, uts, cgroup and time. This option may be given more than once.

-u, --notruncate

Do not truncate text in columns.

-W, --nowrap

Do not use multi-line text in columns.

-T, --tree[=rel]

Use tree-like output format. If process is given as rel, print process tree(s) in each name space. This is default when --tree is not specified. If parent is given, print tree(s) constructed by the parent/child relationship. If owner is given, print tree(s) constructed by the owner/owned relationship. owner is used as default when rel is omitted.

-h, --help

Display help text and exit.

-V, --version

Display version and exit.

EXIT STATUS

The lsns utility exits with one of the following values:

0

Success.

1

General error.

2

An ioctl was unknown to the kernel.

ENVIRONMENT

LSNS_DEBUG=all

enables lsns debug output.

AUTHORS

Karel Zak <kzak@redhat.com>

SEE ALSO

nsenter(1), unshare(1), clone(2), namespaces(7), ioctl_ns(2), ip-netns(8) scols-filter(5)

REPORTING BUGS

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

AVAILABILITY

The lsns 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/>.

2025-02-26 util-linux 2.41