NAME

       nsenter - run program in different namespaces

SYNOPSIS

       nsenter [options] [program [arguments]]

DESCRIPTION

       The nsenter command executes program in the namespace(s) that are specified in the command-line options
       (described below). If program is not given, then "${SHELL}" is run (default: /bin/sh).

       Enterable namespaces are:

       mount namespace
           Mounting and unmounting filesystems will not affect the rest of the system, except for filesystems
           which are explicitly marked as shared (with mount --make-shared; see /proc/self/mountinfo for the
           shared flag). For further details, see mount_namespaces(7) and the discussion of the CLONE_NEWNS flag
           in clone(2).

       UTS namespace
           Setting hostname or domainname will not affect the rest of the system. For further details, see
           uts_namespaces(7).

       IPC namespace
           The process will have an independent namespace for POSIX message queues as well as System V message
           queues, semaphore sets and shared memory segments. For further details, see ipc_namespaces(7).

       network namespace
           The process will have independent IPv4 and IPv6 stacks, IP routing tables, firewall rules, the
           /proc/net and /sys/class/net directory trees, sockets, etc. For further details, see
           network_namespaces(7).

       PID namespace
           Children will have a set of PID to process mappings separate from the nsenter process. nsenter will
           fork by default if changing the PID namespace, so that the new program and its children share the
           same PID namespace and are visible to each other. If --no-fork is used, the new program will be
           exec’ed without forking. For further details, see pid_namespaces(7).

       user namespace
           The process will have a distinct set of UIDs, GIDs and capabilities. For further details, see
           user_namespaces(7).

       cgroup namespace
           The process will have a virtualized view of /proc/self/cgroup, and new cgroup mounts will be rooted
           at the namespace cgroup root. For further details, see cgroup_namespaces(7).

       time namespace
           The process can have a distinct view of CLOCK_MONOTONIC and/or CLOCK_BOOTTIME which can be changed
           using /proc/self/timens_offsets. For further details, see time_namespaces(7).

OPTIONS

       Various of the options below that relate to namespaces take an optional file argument. This should be one
       of the /proc/[pid]/ns/* files described in namespaces(7), or the pathname of a bind mount that was
       created on one of those files.

       -a, --all
           Enter all namespaces of the target process by the default /proc/[pid]/ns/* namespace paths. The
           default paths to the target process namespaces may be overwritten by namespace specific options
           (e.g., --all --mount=[path]).

           The user namespace will be ignored if the same as the caller’s current user namespace. It prevents a
           caller that has dropped capabilities from regaining those capabilities via a call to setns(). See
           setns(2) for more details.

       -t, --target PID
           Specify a target process to get contexts from. The paths to the contexts specified by pid are:

           /proc/pid/ns/mnt
               the mount namespace

           /proc/pid/ns/uts
               the UTS namespace

           /proc/pid/ns/ipc
               the IPC namespace

           /proc/pid/ns/net
               the network namespace

           /proc/pid/ns/pid
               the PID namespace

           /proc/pid/ns/user
               the user namespace

           /proc/pid/ns/cgroup
               the cgroup namespace

           /proc/pid/ns/time
               the time namespace

           /proc/pid/root
               the root directory

           /proc/pid/cwd
               the working directory respectively

       -m, --mount[=file]
           Enter the mount namespace. If no file is specified, enter the mount namespace of the target process.
           If file is specified, enter the mount namespace specified by file.

       -u, --uts[=file]
           Enter the UTS namespace. If no file is specified, enter the UTS namespace of the target process. If
           file is specified, enter the UTS namespace specified by file.

       -i, --ipc[=file]
           Enter the IPC namespace. If no file is specified, enter the IPC namespace of the target process. If
           file is specified, enter the IPC namespace specified by file.

       -n, --net[=file]
           Enter the network namespace. If no file is specified, enter the network namespace of the target
           process. If file is specified, enter the network namespace specified by file.

       -p, --pid[=file]
           Enter the PID namespace. If no file is specified, enter the PID namespace of the target process. If
           file is specified, enter the PID namespace specified by file.

       -U, --user[=file]
           Enter the user namespace. If no file is specified, enter the user namespace of the target process. If
           file is specified, enter the user namespace specified by file. See also the --setuid and --setgid
           options.

       -C, --cgroup[=file]
           Enter the cgroup namespace. If no file is specified, enter the cgroup namespace of the target
           process. If file is specified, enter the cgroup namespace specified by file.

       -T, --time[=file]
           Enter the time namespace. If no file is specified, enter the time namespace of the target process. If
           file is specified, enter the time namespace specified by file.

       -G, --setgid gid
           Set the group ID which will be used in the entered namespace and drop supplementary groups. nsenter
           always sets GID for user namespaces, the default is 0.

       -S, --setuid uid
           Set the user ID which will be used in the entered namespace. nsenter always sets UID for user
           namespaces, the default is 0.

       --preserve-credentials
           Don’t modify UID and GID when enter user namespace. The default is to drops supplementary groups and
           sets GID and UID to 0.

       -r, --root[=directory]
           Set the root directory. If no directory is specified, set the root directory to the root directory of
           the target process. If directory is specified, set the root directory to the specified directory.

       -w, --wd[=directory]
           Set the working directory. If no directory is specified, set the working directory to the working
           directory of the target process. If directory is specified, set the working directory to the
           specified directory.

       -F, --no-fork
           Do not fork before exec’ing the specified program. By default, when entering a PID namespace, nsenter
           calls fork before calling exec so that any children will also be in the newly entered PID namespace.

       -Z, --follow-context
           Set the SELinux security context used for executing a new process according to already running
           process specified by --target PID. (The util-linux has to be compiled with SELinux support otherwise
           the option is unavailable.)

       -V, --version
           Display version information and exit.

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

AUTHORS

       Eric Biederman <biederm@xmission.com>, Karel Zak <kzak@redhat.com>

SEE ALSO

       clone(2), setns(2), namespaces(7)

REPORTING BUGS

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

AVAILABILITY

       The nsenter 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/>.