sudo apt-get update 报错
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.blackfire.io/debian any InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 696DBE66A72D76DA
W: Failed to fetch http://packages.blackfire.io/debian/dists/... The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 696DBE66A72D76DA
W: Some index files failed to download. They have been ignored, or old ones used instead.
终于找到解决方法了
执行sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 696DBE66A72D76DA
再 sudo apt update
y
再sudo apt-get update