code /etc/sysctl.conf
# IPv6
net.ipv6.conf.all.diable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
sudo sysctl -p
Cannot add PPA: 'ppa:~klaus-vormweg/ubuntu/bluefish'.
ERROR: '~klaus-vormweg' user or team does not exist.