在我的 Ubuntu 系统中安装gawk软件包时，我在命令行中收到此错误
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package gawk is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'gawk' has no installation candidate
此外，通过安装任何其他软件包sudo apt-get install也会导致类似的错误。我用谷歌搜索了解决方案，但似乎没有一个有效。
我的 /etc/apt/sources.list 有以下内容：
# deb cdrom:[Ubuntu 16.10 _Yakkety Yak_ - Release amd64 (20161012.2)]/ yakkety main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://in.old-releases.ubuntu.com/ubuntu/ yakkety main restricted
# deb-src http://in.old-releases.ubuntu.com/ubuntu/ yakkety main restricted
## Major bug fix updates produced after the final release of the
## distribution.
deb http://in.old-releases.ubuntu.com/ubuntu/ yakkety-updates main restricted
# deb-src http://in.old-releases.ubuntu.com/ubuntu/ yakkety-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://in.old-releases.ubuntu.com/ubuntu/ yakkety universe
# deb-src http://in.old-releases.ubuntu.com/ubuntu/ yakkety universe
deb http://in.old-releases.ubuntu.com/ubuntu/ yakkety-updates universe
# deb-src http://in.old-releases.ubuntu.com/ubuntu/ yakkety-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://in.old-releases.ubuntu.com/ubuntu/ yakkety multiverse
# deb-src http://in.old-releases.ubuntu.com/ubuntu/ yakkety multiverse
deb http://in.old-releases.ubuntu.com/ubuntu/ yakkety-updates multiverse
# deb-src http://in.old-releases.ubuntu.com/ubuntu/ yakkety-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://in.old-releases.ubuntu.com/ubuntu/ yakkety-backports main restricted universe multiverse
# deb-src http://in.old-releases.ubuntu.com/ubuntu/ yakkety-backports main restricted universe multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu yakkety partner
# deb-src http://archive.canonical.com/ubuntu yakkety partner
deb http://old-releases.ubuntu.com/ubuntu yakkety-security main restricted
# deb-src http://old-releases.ubuntu.com/ubuntu yakkety-security main restricted
deb http://old-releases.ubuntu.com/ubuntu yakkety-security universe
# deb-src http://old-releases.ubuntu.com/ubuntu yakkety-security universe
deb http://old-releases.ubuntu.com/ubuntu yakkety-security multiverse
# deb-src http://old-releases.ubuntu.com/ubuntu yakkety-security multiverse
deb http://archive.ubuntu.com/ubuntu yakkety main universe restricted multiverse
提前致谢。
答案1
编辑你的sources.list如下：
deb http://old-releases.ubuntu.com/ubuntu/ yakkety main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ yakkety-updates main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ yakkety-security main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ yakkety-backports main restricted universe multiverse
保存然后更新：
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install gawk