Ubuntu W: GPG error NO_PUBKEY

Ubuntu系统在执行sudo apt-get update之后,可能会出现如下错误:

>> W: GPG error: http://extras.ubuntu.com trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192

解决办法:

>> gpg --keyserver keyserver.ubuntu.com --recv 16126D3A3E5C1192
>> gpg --export --armor 16126D3A3E5C1192 | sudo apt-key add -