Updated the description of run -d

The goal is to make it more clear this will give you the container id after run completes.

Since stdout is now standard on run, "docker run -d" is the best (or only) way to get the container ID returned from docker after a plain run, but the description (help) does not hint any such thing.

container.go

@@ -100,7 +100,7 @@ func ParseRun(args []string, capabilities *Capabilities) (*Config, *HostConfig,
 
 	flHostname := cmd.String("h", "", "Container host name")
 	flUser := cmd.String("u", "", "Username or UID")
-	flDetach := cmd.Bool("d", false, "Detached mode: leave the container running in the background")
+	flDetach := cmd.Bool("d", false, "Detached mode: Run container in the background, print new container id")
 	flAttach := NewAttachOpts()
 	cmd.Var(flAttach, "a", "Attach to stdin, stdout or stderr.")
 	flStdin := cmd.Bool("i", false, "Keep stdin open even if not attached")

docs/sources/commandline/command/run.rst

@@ -15,7 +15,7 @@
       -a=map[]: Attach to stdin, stdout or stderr.
       -c=0: CPU shares (relative weight)
       -cidfile="": Write the container ID to the file
-      -d=false: Detached mode: leave the container running in the background
+      -d=false: Detached mode: Run container in the background, print new container id
       -e=[]: Set environment variables
       -h="": Container host name
       -i=false: Keep stdin open even if not attached