SHELL

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

how to install apache server in ubuntu

sudo apt update
sudo apt install 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