Implement --version and --help flags

[remi]

I wanted to make sure I was using the latest version of nv so I ran this:

# Current

$ nv --version
nv 2.1.0(2021-06-02) — context specific environment variables
Usage: nv <env files> <command> [arguments...]
$ echo $?
255

The error message (because --version is not a supported flag) output prints the version number by default but it would be nice to have a proper --version flag that would output the version number and then exit with a 0 status, eg.

# Suggestion

$ nv --version
nv 2.1.0(2021-06-02)
$ echo $?
0

Same thing for --help :

# Current

$ nv --help
nv 2.1.0(2021-06-02) — context specific environment variables
Usage: nv <env files> <command> [arguments...]
$ echo $?
255

The usage is printed but again, as an error message. This would be nice:

# Suggestion

$ nv --help
Usage: nv <env files> <command> [arguments...]
$ echo $?
0

Cheers! ✌️

[jcouture]

Thanks for the suggestions.

I will look into it soon.