E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation

apt-get update
apt-get install gnupg
apt-get install gnupg1
apt-get install gnupg2

安裝php7 E: Unable to correct problems, you have held broken packages.

刪除 /etc/apt/sources.list 自己新增的源

ubuntu add-apt-repository command not found解決方法

apt-get install software-properties-common

Invalid command ‘ProxyRequests’, perhaps misspelled or defined by a module not

sudo a2enmod proxy
重啟Apache