docs: update start docs to add examples

docs/reference/commandline/start.md

@@ -22,6 +22,85 @@ Start one or more stopped containers
 
 ## Examples
 
+### Start a container
+
+To start a container, specify the container ID or image name. For example:
+
 ```console
 $ docker start my_container
 ```
+
+### <a name="attach"></a>  Start a container and attach to its STDOUT/STDERR (--attach, -a)
+
+To start a container and attach to its STDOUT/STDERR and forward signals, use the `--attach` or `-a` option. For example, if you create an nginx container named my_nginx_container, you can start it and monitor its logs using the following:
+
+```console
+$ docker create --name my_nginx_container -p 80:80 nginx
+ca5a4351c9c4b43c0b0c69d4d925aa1d8a53a3b33742250ad227f22096accab6
+
+$ docker start -a my_nginx_container
+/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
+/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
+/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
+...
+```
+
+### <a name="checkpoint"></a> Start a container and restore from a checkpoint (--checkpoint) (experimental)
+
+The `--checkpoint` option is an experimental feature, and should not be
+considered stable. To read about experimental daemon options and how to enable
+them, see
+[Daemon configuration file](https://docs.docker.com/engine/reference/commandline/dockerd/#daemon-configuration-file).
+
+To start a container and restore it from a checkpoint, use the `--checkpoint` option. For example:
+
+```console
+$ docker run --security-opt=seccomp:unconfined --name cr -d busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
+db316bda7d64b4154d207a3d659c90c982d0b35a3e177fc396e809a6a93a147f
+
+$ docker checkpoint create cr checkpoint1
+checkpoint1
+
+# <later>
+$ docker start --checkpoint checkpoint1 cr
+```
+
+### <a name="checkpoint-dir"></a>  Start a container and restore from a custom checkpoint storage (--checkpoint-dir) (experimental)
+
+The `--checkpoint-dir` option is an experimental feature, and should not be
+considered stable. To read about experimental daemon options and how to enable
+them, see
+[Daemon configuration file](https://docs.docker.com/engine/reference/commandline/dockerd/#daemon-configuration-file).
+
+To start a container and restore it from a checkpoint in a custom checkpoint storage directory, use the `--checkpoint-dir` option. For example:
+
+```console
+$ docker run --security-opt=seccomp:unconfined --name cr -d busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'
+db316bda7d64b4154d207a3d659c90c982d0b35a3e177fc396e809a6a93a147f
+
+$ docker checkpoint create --checkpoint-dir /path/to/checkpoints cr checkpoint2
+checkpoint2
+
+# <later>
+$ docker start --checkpoint-dir /path/to/checkpoints --checkpoint checkpoint2 cr
+```
+
+### <a name="detach-keys"></a> Start a container and override the detach key sequence (--detach-keys)
+
+To start a container and override the key sequence for detaching a container, use the `--detach-keys` option. For example to change the detach sequence to `ctrl` plus `x`, use the following:
+
+```console
+$ docker start -a --detach-keys="ctrl-x" my_container
+```
+
+### <a name="interactive"></a> Start a container and attach to its STDIN (--interactive, -i)
+
+To start a container and attach to its STDIN, use the `--interactive` or `-i` option. For example, if you create an ubuntu container named my_ubuntu_container, you can start it and interact with its shell using the following:
+
+```console
+$ docker create -it --name my_ubuntu_container ubuntu
+6facdc392ec364d53d5cca760791d33b173d89525aff8f6f7c73a68bda0ab33c
+
+$ docker start -i my_ubuntu_container
+root@6facdc392ec3:/#
+```