daria@samsung-laptop:~$ gpg --keyserver hkp://keys.gnupg.net --recv-keys D39DC0E3
gpg: requesting key D39DC0E3 from hkp server keys.gnupg.net
?: keys.gnupg.net: Host not found
gpgkeys: HTTP fetch error 7: couldn't connect: Success
gpg: no valid OpenPGP data found.
gpg: Total number processed: 0
daria@samsung-laptop:~$ \curl -sSL https://get.rvm.io | bash -s stable
Downloading https://github.com/wayneeseguin/rvm/archive/1.26.9.tar.gz
Downloading https://github.com/wayneeseguin/rvm/releases/download/1.26.9/1.26.9.tar.gz.asc
gpg: Signature made Ср. 07 янв. 2015 14:55:10 MSK using RSA key ID BF04FF17
gpg: Can't check signature: No public key
Warning, RVM 1.26.0 introduces signed releases and automated check of signatures when GPG software found.
Assuming you trust Michal Papis import the mpapis public key (downloading the signatures).

GPG signature verification failed for '/home/daria/.rvm/archives/rvm-1.26.9.tgz' - 'https://github.com/wayneeseguin/rvm/releases/download/1.26.9/1.26.9.tar.gz.asc'!
try downloading the signatures:

    gpg2 --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3

or if it fails:

    command curl -sSL https://rvm.io/mpapis.asc | gpg2 --import -

the key can be compared with:

    https://rvm.io/mpapis.asc
    https://keybase.io/mpapis

daria@samsung-laptop:~$ rvm
No command 'rvm' found, but there are 20 similar ones
rvm: command not found