我想在ubuntu上将R从3.4.4更新到3.5。我遵循这个How to upgrade R in ubuntu?，但总是遇到一些麻烦
我的尝试：
1，su
2，vi /etc/apt/sources.list并添加 deb https://mirrors.ustc.edu.cn/CRAN/bin/linux/ubuntu/ xenial /
3，gpg --keyserver keyserver.ubuntu.com --recv-key E084DAB9
4，gpg -a --export E084DAB9 | sudo apt键添加-
5，sudo apt-get更新&& sudo apt-get升级＃遇到一些麻烦
6，apt-get install r-base-dev＃也遇到一些麻烦
Err:27 http://ppa.launchpad.net/nebc/bio-linux/ubuntu xenial/main amd64 Packages 404 Not Found
W: GPG error: http://dl.google.com/linux/chrome/deb stable Release: The followin g signatures couldn't be verified because the public key is not available: NO_PU BKEY 6494C6D6997C215E
W: The repository 'http://dl.google.com/linux/chrome/deb stable Release' is not signed.
N: Data from such a repository can't be authenticated and is therefore potential ly dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration deta ils.
N: Skipping acquire of configured file 'main/binary-i386/Packages' as repository 'http://dl.google.com/linux/chrome/deb stable InRelease' doesn't support archit ecture 'i386'
W: The repository 'http://ppa.launchpad.net/nebc/bio-linux/ubuntu xenial Release ' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potential ly dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration deta ils.
E: Failed to fetch http://ppa.launchpad.net/nebc/bio-linux/ubuntu/dists/xenial/m ain/binary-amd64/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
x/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not Found^C-linu
root@omnisky:~# sudo apt-get install r-base-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
r-base-dev is already the newest version (3.4.4-1xenial0). # why?
The following package was automatically installed and is no longer required:
snapd-login-service
Use 'sudo apt autoremove' to remove it.
0 upgraded, 0 newly installed, 0 to remove and 29 not upgraded.