add podman container|image exists

Add an exists subcommand to podman container and podman image that allows
users to verify the existence of a container or image by ID or name.  The return
code can be 0 (success), 1 (failed to find), or 125 (failed to work with runtime).

Issue #1845

Signed-off-by: baude <bbaude@redhat.com>

4 files changed, 82 insertions, 0 deletions

diff --git a/docs/podman-container-exists.1.md b/docs/podman-container-exists.1.md
new file mode 100644
index 000000000..76701e2c2
--- /dev/null
+++ b/docs/podman-container-exists.1.md
@@ -0,0 +1,40 @@
+% PODMAN(1) Podman Man Pages
+% Brent Baude
+% November 2018
+# NAME
+podman-container-exists- Check if a container exists in local storage
+
+# SYNOPSIS
+**podman container exists**
+[**-h**|**--help**]
+CONTAINER
+
+# DESCRIPTION
+**podman container exists** checks if a container exists in local storage. The **ID** or **Name**
+of the container may be used as input.  Podman will return an exit code
+of `0` when the container is found.  A `1` will be returned otherwise. An exit code of `125` indicates there
+was an issue accessing the local storage.
+
+## Examples ##
+
+Check if an container called `webclient` exists in local storage (the container does actually exist).
+```
+$ sudo podman container exists webclient
+$ echo $?
+0
+$
+```
+
+Check if an container called `webbackend` exists in local storage (the container does not actually exist).
+```
+$ sudo podman container exists webbackend
+$ echo $?
+1
+$
+```
+
+## SEE ALSO
+podman(1)
+
+# HISTORY
+November 2018, Originally compiled by Brent Baude (bbaude at redhat dot com)
diff --git a/docs/podman-container.1.md b/docs/podman-container.1.md
index 67d42bfef..aa5dfa82c 100644
--- a/docs/podman-container.1.md
+++ b/docs/podman-container.1.md
@@ -20,6 +20,7 @@ The container command allows you to manage containers
 | create   | [podman-create(1)](podman-create.1.md)              | Create a new container.                                                      |
 | diff     | [podman-diff(1)](podman-diff.1.md)                  | Inspect changes on a container or image's filesystem.                        |
 | exec     | [podman-exec(1)](podman-exec.1.md)                  | Execute a command in a running container.                                    |
+| exists   | [podman-exists(1)](podman-container-exists.1.md)    | Check if a container exists in local storage                                 |
 | export   | [podman-export(1)](podman-export.1.md)              | Export a container's filesystem contents as a tar archive.                   |
 | inspect  | [podman-inspect(1)](podman-inspect.1.md)            | Display a container or image's configuration.                                |
 | kill     | [podman-kill(1)](podman-kill.1.md)                  | Kill the main process in one or more containers.                             |
diff --git a/docs/podman-image-exists.1.md b/docs/podman-image-exists.1.md
new file mode 100644
index 000000000..e04c23721
--- /dev/null
+++ b/docs/podman-image-exists.1.md
@@ -0,0 +1,40 @@
+% PODMAN(1) Podman Man Pages
+% Brent Baude
+% November 2018
+# NAME
+podman-image-exists- Check if an image exists in local storage
+
+# SYNOPSIS
+**podman image exists**
+[**-h**|**--help**]
+IMAGE
+
+# DESCRIPTION
+**podman image exists** checks if an image exists in local storage. The **ID** or **Name**
+of the image may be used as input.  Podman will return an exit code
+of `0` when the image is found.  A `1` will be returned otherwise. An exit code of `125` indicates there
+was an issue accessing the local storage.
+
+## Examples ##
+
+Check if an image called `webclient` exists in local storage (the image does actually exist).
+```
+$ sudo podman image exists webclient
+$ echo $?
+0
+$
+```
+
+Check if an image called `webbackend` exists in local storage (the image does not actually exist).
+```
+$ sudo podman image exists webbackend
+$ echo $?
+1
+$
+```
+
+## SEE ALSO
+podman(1)
+
+# HISTORY
+November 2018, Originally compiled by Brent Baude (bbaude at redhat dot com)
diff --git a/docs/podman-image.1.md b/docs/podman-image.1.md
index 33de0456f..446f8667d 100644
--- a/docs/podman-image.1.md
+++ b/docs/podman-image.1.md
@@ -14,6 +14,7 @@ The image command allows you to manage images
 | Command  | Man Page                                  | Description                                                                    |
 | -------- | ----------------------------------------- | ------------------------------------------------------------------------------ |
 | build    | [podman-build(1)](podman-build.1.md)      | Build a container using a Dockerfile.                                          |
+| exists   | [podman-exists(1)](podman-image-exists.1.md)      | Check if a image exists in local storage                                          |
 | history  | [podman-history(1)](podman-history.1.md)  | Show the history of an image.                                                  |
 | import   | [podman-import(1)](podman-import.1.md)    | Import a tarball and save it as a filesystem image.                            |
 | inspect  | [podman-inspect(1)](podman-inspect.1.md)  | Display a image or image's configuration.                                      |