Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Cic17:External/openSUSE_Tumbleweed/home:Cic17:External.repo
zypper refresh
zypper install brightnessctl
Для openSUSE Slowroll запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Cic17:External/openSUSE_Slowroll/home:Cic17:External.repo
zypper refresh
zypper install brightnessctl
Для 16.0 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Cic17:External/16.0/home:Cic17:External.repo
zypper refresh
zypper install brightnessctl
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/home:Cic17:External/15.6/home:Cic17:External.repo
zypper refresh
zypper install brightnessctl