According to the docs, only "my-cmd --version" should output the version number, but I have found that commander also picks up the string 'version' anywhere in the arguments.

As an example of where this causes problems, you can have a look at a little utility I wrote called pick_json. It is used it to extract fields from json on stdin.

$ echo '{ "name" : "myapp", "version" : "3.4.5" }' > appinfo.json

$ pick_json name < appinfo.json
myapp

$ pick_json version < appinfo.json  #WTF moment
1.1.2

$ pick_json --version
1.1.2

As you can see, instead of picking the version field from the json, it shows the version number of pick_json. This is not inline with the docs.