[cmd] Notation for "mandatory" and "optional" parameters in "help shell_cmd" output

[Adarsh Babu Kalepalli]

Hi,

When we type "help shell_command" at u-boot console.
The syntax for the command usage is displayed.

In most of the cases I noticed parameters enclosed in '[]' or/and '<>'
or just the sub-command string is provided.

>From the help of most of the commands, and on using them I observed that
parameters enclosed in
                -'[]' could be optional
                -'<>' could be mandatory

In some cases, the mandatory parameters were not enclosed in "<>" .
For ex.
            env ask name [message] [size] - ask for environment variable
            env edit name - edit environment variable
            env exists name - tests for existence of variable

in the above case "name" seems to be a mandatory parameter.

Could you please let me know the notation we follow to indicate the
mandatory and optional input parameters for shell commands in their syntax
(displayed through help) ??

Regards,
Adarsh