docs: update documentation of commands delete,purge,rmdir,rmdirs

cmd/rmdirs/rmdirs.go

@@ -20,15 +20,21 @@ func init() {
 var rmdirsCmd = &cobra.Command{
 	Use:   "rmdirs remote:path",
 	Short: `Remove empty directories under the path.`,
-	Long: `This removes any empty directories (or directories that only contain
-empty directories) under the path that it finds, including the path if
-it has nothing in.
+	Long: `
+This recursively removes any empty directories (including directories
+that only contain empty directories), that it finds under the path.
+The root path itself will also be removed if it is empty, unless
+you supply the ` + "`--leave-root`" + ` flag.
 
-If you supply the --leave-root flag, it will not remove the root directory.
+Use command ` + "`rmdir`" + ` to delete just the empty directory
+given by path, not recurse.
 
 This is useful for tidying up remotes that rclone has left a lot of
-empty directories in.
+empty directories in. For example the ` + "`delete`" + ` command will
+delete files but leave the directory structure (unless used with
+option ` + "`--rmdirs`" + `).
 
+To delete a path and any objects in it, use ` + "`purge`" + ` command.
 `,
 	Run: func(command *cobra.Command, args []string) {
 		cmd.CheckArgs(1, 1, command, args)