我在更新时遇到了这个错误。我阅读了有关此问题的问题和答案，但重点是签名密钥。它没有返回签名密钥！
Get:1 http://archive.canonical.com lucid Release.gpg [198B]
Ign http://archive.canonical.com/ lucid/partner Translation-en_US
...
...
...
Get:24 http://archive.ubuntu.com lucid-security/main Packages [380kB]
Get:25 http://archive.ubuntu.com lucid-security/restricted Packages [14B]
Get:26 http://archive.ubuntu.com lucid-security/multiverse Packages [4,556B]
Get:27 http://archive.ubuntu.com lucid-security/main Sources [118kB]
Get:28 http://archive.ubuntu.com lucid-security/restricted Sources [14B]
Get:29 http://archive.ubuntu.com lucid-security/universe Packages [125kB]
Get:30 http://archive.ubuntu.com lucid-security/universe Sources [34.5kB]
Fetched 12.8MB in 10min 33s (20.3kB/s)
Reading package lists... Done
W: GPG error: http://archive.canonical.com lucid Release: Unknown error executing gpgv
W: GPG error: http://archive.ubuntu.com lucid Release: Unknown error executing gpgv
W: GPG error: http://archive.ubuntu.com lucid-updates Release: Unknown error executing gpgv
W: GPG error: http://archive.ubuntu.com lucid-security Release: Unknown error executing gpgv
答案1
最后，修复。
我在 /lib 中搜索并找到另一个“libreadline.so.6”并将其替换，问题就解决了。
感谢您的关注。
答案2
尝试sudo apt-get clean然后再次运行更新命令。
答案3
嗯...这里也有同样的问题（ubuntu 12.04，64位）。这对我有用：
sudo mv /usr/local/lib/libreadline.so.6 /usr/local/lib/libreadline_problem.so.6
sudo mv /usr/local/lib/libreadline.so.6.2 /usr/local/lib/libreadline_problem.so.6.2
sudo ln -s /lib/x86_64-linux-gnu/libreadline.so.6 /usr/local/lib/libreadline.so.6
sudo ln -s /lib/x86_64-linux-gnu/libreadline.so.6.2 /usr/local/lib/libreadline.so.6.2
sudo apt-get update
：）
答案4
请运行以下命令并手动添加密钥：
gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv KEYNAME