lsblk: fix -D segfault

[thirdparty/util-linux.git] / sys-utils / unshare.1

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.TH UNSHARE 1 "July 2013" "util-linux" "User Commands"
.SH NAME
unshare \- run program with some namespaces unshared from parent
.SH SYNOPSIS
.B unshare
.RI [ options ]
.I program
.RI [ arguments ]
.SH DESCRIPTION
Unshares the indicated namespaces from the parent process and then executes
the specified program.  The namespaces to be unshared are indicated via
options.  Unshareable namespaces are:
.TP
.BR "mount namespace"
Mounting and unmounting filesystems will not affect the rest of the system
(\fBCLONE_NEWNS\fP flag), except for filesystems which are explicitly marked as
shared (with \fBmount --make-shared\fP; see \fI/proc/self/mountinfo\fP for the
\fBshared\fP flags).
.TP
.BR "UTS namespace"
Setting hostname or domainname will not affect the rest of the system.
(\fBCLONE_NEWUTS\fP flag)
.TP
.BR "IPC namespace"
The process will have an independent namespace for System V message queues,
semaphore sets and shared memory segments.  (\fBCLONE_NEWIPC\fP flag)
.TP
.BR "network namespace"
The process will have independent IPv4 and IPv6 stacks, IP routing tables,
firewall rules, the \fI/proc/net\fP and \fI/sys/class/net\fP directory trees,
sockets, etc.  (\fBCLONE_NEWNET\fP flag)
.TP
.BR "pid namespace"
Children will have a distinct set of PID to process mappings from their parent.
(\fBCLONE_NEWPID\fP flag)
.TP
.BR "user namespace"
The process will have a distinct set of UIDs, GIDs and capabilities.
(\fBCLONE_NEWUSER\fP flag)
.PP
See \fBclone\fR(2) for the exact semantics of the flags.
.SH OPTIONS
.TP
.BR \-h , " \-\-help"
Display help text and exit.
.TP
.BR \-i , " \-\-ipc"
Unshare the IPC namespace.
.TP
.BR \-m , " \-\-mount"
Unshare the mount namespace.
.TP
.BR \-n , " \-\-net"
Unshare the network namespace.
.TP
.BR \-p , " \-\-pid"
Unshare the pid namespace.
See also the \fB--fork\fP and \fB--mount-proc\fP options.
.TP
.BR \-u , " \-\-uts"
Unshare the UTS namespace.
.TP
.BR \-U , " \-\-user"
Unshare the user namespace.
.TP
.BR \-f , " \-\-fork"
Fork the specified \fIprogram\fR as a child process of \fBunshare\fR rather than
running it directly.  This is useful when creating a new pid namespace.
.TP
.BR \-\-mount-proc "[=\fImountpoint\fP]"
Just before running the program, mount the proc filesystem at the \fImountpoint\fP
(default is /proc).  This is useful when creating a new pid namespace.  It also
implies creating a new mount namespace since the /proc mount would otherwise
mess up existing programs on the system.
.SH SEE ALSO
.BR unshare (2),
.BR clone (2)
.SH BUGS
None known so far.
.SH AUTHOR
Mikhail Gusarov <dottedmag@dottedmag.net>
.SH AVAILABILITY
The unshare command is part of the util-linux package and is available from
ftp://ftp.kernel.org/pub/linux/utils/util-linux/.