1NSENTER(1)                       User Commands                      NSENTER(1)
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NAME

6       nsenter - run program with namespaces of other processes
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SYNOPSIS

9       nsenter [options] [program [arguments]]
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DESCRIPTION

12       Enters  the namespaces of one or more other processes and then executes
13       the specified program. If program is not given,  then  ``${SHELL}''  is
14       run (default: /bin/sh).
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16       Enterable namespaces are:
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18       mount namespace
19              Mounting  and unmounting filesystems will not affect the rest of
20              the system, except for filesystems which are  explicitly  marked
21              as  shared  (with  mount --make-shared; see /proc/self/mountinfo
22              for the shared flag).  For  further  details,  see  mount_names‐
23              paces(7) and the discussion of the CLONE_NEWNS flag in clone(2).
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25       UTS namespace
26              Setting  hostname  or domainname will not affect the rest of the
27              system.  For further details, see namespaces(7) and the  discus‐
28              sion of the CLONE_NEWUTS flag in clone(2).
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30       IPC namespace
31              The process will have an independent namespace for POSIX message
32              queues as well as System V message queues,  semaphore  sets  and
33              shared  memory segments.  For further details, see namespaces(7)
34              and the discussion of the CLONE_NEWIPC flag in clone(2).
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36       network namespace
37              The process will have independent IPv4 and IPv6 stacks, IP rout‐
38              ing  tables,  firewall  rules,  the /proc/net and /sys/class/net
39              directory trees, sockets, etc.  For further details, see  names‐
40              paces(7)   and  the  discussion  of  the  CLONE_NEWNET  flag  in
41              clone(2).
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43       PID namespace
44              Children will have a set of PID  to  process  mappings  separate
45              from  the  nsenter  process  For further details, see pid_names‐
46              paces(7) and the discussion of the CLONE_NEWPID flag in  nsenter
47              will  fork by default if changing the PID namespace, so that the
48              new program and its children share the same  PID  namespace  and
49              are  visible  to each other.  If --no-fork is used, the new pro‐
50              gram will be exec'ed without forking.
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52       user namespace
53              The process will have a distinct set of UIDs, GIDs and capabili‐
54              ties.   For further details, see user_namespaces(7) and the dis‐
55              cussion of the CLONE_NEWUSER flag in clone(2).
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57       cgroup namespace
58              The process will have a virtualized view  of  /proc/self/cgroup,
59              and  new  cgroup  mounts  will be rooted at the namespace cgroup
60              root.  For further details,  see  cgroup_namespaces(7)  and  the
61              discussion of the CLONE_NEWCGROUP flag in clone(2).
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63       See clone(2) for the exact semantics of the flags.
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OPTIONS

66       Various of the options below that relate to namespaces take an optional
67       file argument.  This  should  be  one  of  the  /proc/[pid]/ns/*  files
68       described in namespaces(7).
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70       -a, --all
71              Enter  all  namespaces  of  the  target  process  by the default
72              /proc/[pid]/ns/* namespace paths. The default paths to the  tar‐
73              get  process namespaces may be overwritten by namespace specific
74              options (e.g. --all --mount=[path]).
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76              The user namespace will be ignored if the same as  the  caller's
77              current  user  namespace.  It prevents a caller that has dropped
78              capabilities from regaining those capabilities  via  a  call  to
79              setns().  See setns(2) for more details.
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81       -t, --target pid
82              Specify a target process to get contexts from.  The paths to the
83              contexts specified by pid are:
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85              /proc/pid/ns/mnt    the mount namespace
86              /proc/pid/ns/uts    the UTS namespace
87              /proc/pid/ns/ipc    the IPC namespace
88              /proc/pid/ns/net    the network namespace
89              /proc/pid/ns/pid    the PID namespace
90              /proc/pid/ns/user   the user namespace
91              /proc/pid/ns/cgroup the cgroup namespace
92              /proc/pid/root      the root directory
93              /proc/pid/cwd       the working directory respectively
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95       -m, --mount[=file]
96              Enter the mount namespace.  If no file is specified,  enter  the
97              mount  namespace  of  the target process.  If file is specified,
98              enter the mount namespace specified by file.
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100       -u, --uts[=file]
101              Enter the UTS namespace.  If no file is specified, enter the UTS
102              namespace  of  the  target process.  If file is specified, enter
103              the UTS namespace specified by file.
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105       -i, --ipc[=file]
106              Enter the IPC namespace.  If no file is specified, enter the IPC
107              namespace  of  the  target process.  If file is specified, enter
108              the IPC namespace specified by file.
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110       -n, --net[=file]
111              Enter the network namespace.  If no file is specified, enter the
112              network  namespace of the target process.  If file is specified,
113              enter the network namespace specified by file.
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115       -p, --pid[=file]
116              Enter the PID namespace.  If no file is specified, enter the PID
117              namespace  of  the  target process.  If file is specified, enter
118              the PID namespace specified by file.
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120       -U, --user[=file]
121              Enter the user namespace.  If no file is  specified,  enter  the
122              user  namespace  of  the  target process.  If file is specified,
123              enter the user  namespace  specified  by  file.   See  also  the
124              --setuid and --setgid options.
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126       -C, --cgroup[=file]
127              Enter  the cgroup namespace.  If no file is specified, enter the
128              cgroup namespace of the target process.  If file  is  specified,
129              enter the cgroup namespace specified by file.
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131       -G, --setgid gid
132              Set the group ID which will be used in the entered namespace and
133              drop supplementary groups.  nsenter(1) always sets GID for  user
134              namespaces, the default is 0.
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136       -S, --setuid uid
137              Set  the  user  ID  which will be used in the entered namespace.
138              nsenter(1) always sets UID for user namespaces, the  default  is
139              0.
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141       --preserve-credentials
142              Don't  modify UID and GID when enter user namespace. The default
143              is to drops supplementary groups and sets GID and UID to 0.
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145       -r, --root[=directory]
146              Set the root directory.  If no directory is specified,  set  the
147              root  directory to the root directory of the target process.  If
148              directory is specified, set the root directory to the  specified
149              directory.
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151       -w, --wd[=directory]
152              Set  the  working  directory.  If no directory is specified, set
153              the working directory to the working  directory  of  the  target
154              process.   If  directory is specified, set the working directory
155              to the specified directory.
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157       -F, --no-fork
158              Do not fork before exec'ing the specified program.  By  default,
159              when entering a PID namespace, nsenter calls fork before calling
160              exec so that any children will also be in the newly entered  PID
161              namespace.
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163       -Z, --follow-context
164              Set  the  SELinux  security  context  used  for  executing a new
165              process according to already running process specified by --tar‐
166              get PID. (The util-linux has to be compiled with SELinux support
167              otherwise the option is unavailable.)
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169       -V, --version
170              Display version information and exit.
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172       -h, --help
173              Display help text and exit.
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SEE ALSO

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

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

183       The nsenter command is part of the util-linux package and is  available
184       from Linux Kernel Archive ⟨https://www.kernel.org/pub/linux/utils/util-
185       linux/⟩.
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189util-linux                         June 2013                        NSENTER(1)
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