Interesting, there must be a fix out there somewhere - but so far I find it rather unclear where it is included.
On Ubuntu 14.04.3 LTS with software-properties-common 0.92.37.5 it works in the requested way:
=> sudo apt-add-repository ppa:
Cannot add PPA: 'ppa:'.
Please check that the PPA name or format is correct.
But on 15.10 beta2 with software-properties-common 0.96.10 it fails as described before.
Interesting, there must be a fix out there somewhere - but so far I find it rather unclear where it is included.
On Ubuntu 14.04.3 LTS with software- properties- common 0.92.37.5 it works in the requested way:
=> sudo apt-add-repository ppa:
Cannot add PPA: 'ppa:'.
Please check that the PPA name or format is correct.
But on 15.10 beta2 with software- properties- common 0.96.10 it fails as described before.
Need to dig through the repositories ...