NAME

       nsenter - run program with namespaces of other processes

SYNOPSIS

       nsenter [options] [program [arguments]]

DESCRIPTION

       Enters  the namespaces of one or more other processes and then executes the specified program. 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
              namespaces(7) and the discussion of the CLONE_NEWUTS flag in clone(2).

       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 namespaces(7)
              and the discussion of the CLONE_NEWIPC flag in clone(2).

       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
              namespaces(7) and the discussion of the CLONE_NEWNET flag in clone(2).

       PID namespace
              Children will have a set of PID to process mappings separate from the nsenter process For  further
              details, see pid_namespaces(7) and the discussion of the CLONE_NEWPID flag in 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.

       user namespace
              The process will have a distinct set of UIDs, GIDs and capabilities.   For  further  details,  see
              user_namespaces(7) and the discussion of the CLONE_NEWUSER flag in clone(2).

       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)  and  the
              discussion of the CLONE_NEWCGROUP flag in clone(2).

       See clone(2) for the exact semantics of the flags.

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).

       -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/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.

       -G, --setgid gid
              Set the group ID which will be used in  the  entered  namespace  and  drop  supplementary  groups.
              nsenter(1) 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(1) 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.

SEE ALSO

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

AUTHORS

       Eric Biederman ⟨biederm@xmission.com⟩
       Karel Zak ⟨kzak@redhat.com⟩

AVAILABILITY

       The  nsenter  command  is  part  of  the  util-linux  package  and is available from Linux Kernel Archive
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.