Magento 2 command line install (too many arguments)

I think you have forgot about the -- in front of the command. (So it seems in your screenshot).

I had a similar issue and the correct installation command is:

php bin/magento setup:install 
--base-url="http://example.co.uk/" 
--db-host="localhost" 
--db-name="databasename" 
--db-user="databaseuser" 
--db-password="databasepass" 
--admin-firstname="Yourname" 
--admin-lastname="Yourname" 
--admin-email="[email protected]" 
--admin-user="admin" 
--admin-password="setpasswordhere" 
--language="en_GB" 
--currency="GBP" 
--timezone="Europe/London" 
--use-rewrites="1" 
--backend-frontname="admin"

Install Magento 2 using CLI

As mentioned, in your case command line options for the Magento 2 CLI installer require -- before the option name (e.g --base-url="example.com")