Install Java
You can skip it if you've already had java in your system.
sudo add-apt-repository -y ppa:webupd8team/java
sudo apt-get update
sudo aptitude -y install oracle-java8-installer
mkdir ~/tmp; cd ~/tmp
Install Cassandra
wget http://www.us.apache.org/dist/cassandra/2.2.1/apache-cassandra-2.2.1-bin.tar.gz
tar -xvzf apache-cassandra-2.2.1-bin.tar.gz
mv apache-cassandra-2.2.1 ~/cassandra
sudo mkdir /var/lib/cassandra
sudo mkdir /var/log/cassandra
sudo chown -R $USER:$GROUP /var/lib/cassandra
sudo chown -R $USER:$GROUP /var/log/cassandra
export CASSANDRA_HOME=~/cassandra
export PATH=$PATH:$CASSANDRA_HOME/bin
Run Cassandra
cassandra -f