Add unshare to podman

This command lets the user run a command in a new user namespace like `unshare -u`.
It uses the implementation of unshare in buildah. ( fixes #1388 )

Signed-off-by: Divyansh Kamboj <kambojdivyansh2000@gmail.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/docs/podman-unshare.1.md b/docs/podman-unshare.1.md
new file mode 100644
index 000000000..a7f018ce1
--- /dev/null
+++ b/docs/podman-unshare.1.md
@@ -0,0 +1,37 @@
+% podman-unshare "1"
+
+## NAME
+podman\-unshare - Run a command inside of a modified user namespace.
+
+## SYNOPSIS
+**podman unshare** [*options*] [**--**] [*command*]
+
+## DESCRIPTION
+Launches a process (by default, *$SHELL*) in a new user namespace. The user
+namespace is configured so that the invoking user's UID and primary GID appear
+to be UID 0 and GID 0, respectively.  Any ranges which match that user and
+group in /etc/subuid and /etc/subgid are also mapped in as themselves with the
+help of the *newuidmap(1)* and *newgidmap(1)* helpers.
+
+podman unshare is useful for troubleshooting unprivileged operations and for
+manually clearing storage and other data related to images and containers.
+
+It is also useful if you want to use the `podman mount` command.  If an unprivileged users wants to mount and work with a container, then they need to execute
+podman unshare.  Executing `podman mount` fails for unprivileged users unless the user is running inside a `podman unshare` session.
+
+## EXAMPLE
+
+```
+$ podman unshare id
+uid=0(root) gid=0(root) groups=0(root),65534(nobody)
+
+$ podman unshare cat /proc/self/uid_map /proc/self/gid_map
+         0       1000          1
+         1      10000      65536
+         0       1000          1
+         1      10000      65536
+```
+
+
+## SEE ALSO
+podman(1), podman-mount(1), namespaces(7), newuidmap(1), newgidmap(1), user\_namespaces(7)
\ No newline at end of file