今天突然發現web頁面不能解析了，直接返回php代碼了，想起來可能是由於不小心更新過apt 源，有一次安裝了php8，後來又卸載，導致的，查了一下，發現是libapache2-mod-php沒安裝。
我就 sudo apt-get install libapache2-mod-php 直接執行安裝了，結果發現又把php8安裝上來了，大意了，現在源最新的php是8，然後又 sudo apt remove php8 系列相關，然後重新search
$ sudo apt search libapache2-mod-php7.4 Sorting... Done Full Text Search... Done libapache2-mod-php7.4/focal,now 7.4.23-1+ubuntu20.04.1+deb.sury.org+1 amd64 [residual-config] server-side, HTML-embedded scripting language (Apache 2 module) php7.4-fpm/focal,now 7.4.23-1+ubuntu20.04.1+deb.sury.org+1 amd64 [installed] server-side, HTML-embedded scripting language (FPM-CGI binary)
然後就 sudo apt-get install libapache2-mod-php7.4 跑一下
$ sudo apt-get install libapache2-mod-php7.4 Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: libapache2-mod-php7.4 0 upgraded, 1 newly installed, 0 to remove and 17 not upgraded. Need to get 0 B/1,371 kB of archives. After this operation, 4,680 kB of additional disk space will be used. Selecting previously unselected package libapache2-mod-php7.4. (Reading database ... 241958 files and directories currently installed.) Preparing to unpack .../libapache2-mod-php7.4_7.4.23-1+ubuntu20.04.1+deb.sury.org+1_amd64.deb ... Unpacking libapache2-mod-php7.4 (7.4.23-1+ubuntu20.04.1+deb.sury.org+1) ... Setting up libapache2-mod-php7.4 (7.4.23-1+ubuntu20.04.1+deb.sury.org+1) ... apache2_invoke: Enable module php7.4 Processing triggers for libapache2-mod-php7.4 (7.4.23-1+ubuntu20.04.1+deb.sury.org+1) ...
執行完畢重啓apache，好了，代碼按7.4解析了