SHELL

reinstal apache2 ubuntu

sudo apt-get --purge remove apache2
sudo apt-get autoremove
sudo apt-get install apache2
sudo /etc/init.d/apache2 restart

linux apache start

sudo service apache2 start
sudo service apache2 restart
sudo service apache2 stop

OR 

sudo /etc/init.d/apache2 start
sudo /etc/init.d/apache2 restart
sudo /etc/init.d/apache2 stop

install apache2 ubuntu

sudo apt update
sudo apt install apache2

ubuntu apache2 command

sudo systemctl start apache2
sudo systemctl stop apache2
sudo systemctl restart apache2
sudo systemctl status apache2

start apache server in ubuntu

# Start Apache 2 server on Linux/Unix
sudo apt install apache2

# allow uncomplicated firewall
sudo ufw allow 'Apache'

# start the server
sudo service apache2 start

# /var/www/html/index.html is now live on =>
http://localhost/ 

# Stop Apache 2 server on Linux/Unix
sudo service apache2 stop

#remove apache2 packages
$ sudo apt-get purge apache2 apache2-utils apache2-bin apache2.2-common

# cleanup
$ sudo apt-get autoremove