qrepolist:
deb http://q4os.org/q4repo q4os-2-0-cn main
deb http://q4os.org/qtderepo stretch main
deb http://ftp.debian.org/debian/ stretch main contrib non-free
deb http://security.debian.org/debian-security/ stretch/updates main contrib non-free
deb http://ftp.debian.org/debian/ stretch-updates main contrib non-free
