I'm trying to run forge 1.7.2 from command line, and I get the error saying I have missed the version option. However, I have defined it, it looks like this:

 

@/c java -XX:MaxPermSize=256m -Xms1324M -Xmx1961M -Djava.library.path="%APPDATA%\.ssmc\versions\Classic\Natives" -cp "%APPDATA%\.ssmc\lib\*;%APPDATA%\.ssmc\versions\Classic\Classic.jar;" net.minecraft.client.main.Main --session (Default) --username  --version 1.7.2 --assetIndex 1.7.2 --assetsDir "%APPDATA%\.ssmc\assets" --gameDir "%APPDATA%\.ssmc" --accessToken (Default)

That was the question. Thank you for your really useful answer.

Typical cause for this is half-baked 'cracked' launchers and the like. Launching minecraft is not hard the specs are out there. Either use a reputable launcher and see what it does or don't.

This is not a Forge issue. The error blatently tells you what's wrong. There is no reason for us to support you if you can't at least give a good answer.