NextCloud

Assumes Ubuntu 20.04, stable19 branch (c. September 2020).

Install prerequisites

sudo apt install apache2 libapache2-mod-php7.4 \
   php7.4-{curl,gd,intl,json,mbstring,opcache,pgsql,tidy,xmlrpc,xsl,zip}
   php-{imagick,redis} composer dehydrated postgresql redis-server

cd /var/www
git clone https://github.com/nextcloud/server.git nextcloud && cd nextcloud
git submodule update --init --recursive
chown www-data:www-data config apps .htaccess
sudo -u www-data ./occ maintenance:update:htaccess

mkdir /var/lib/nextcloud/data
chown -R www-data:www-data /var/lib/nextcloud

Create a database. Bump up the PHP memory limit to at least 512M.