Drush is a command-line shell and scripting interface for Drupal, a veritable Swiss Army knife designed to make life easier for those who spend their working hours hacking away at the command prompt.
Installing on the cloud hosting platform can be a little bit tricky, but it should be much easier if you follow these steps.
1) Log-in to https://control.gridhost.co.uk and activate Secure Shell on the domain you wish to use Drush with
2) Wait around 5-10 minutes for your jailshell environment to fully initialise.
3) Log-in to SSH using your favourite SSH client
4) Now, run the following commands:-
echo "alias php='/usr/bin/php-5.6-cli'" >> .bashrc
echo "PATH=~:/usr/local/bin:/bin:/usr/bin" >> .bashrc
ln -s /usr/bin/php-5.6-cli php
So now the environment is correctly configured for your installation of Drush.
unzip -q master.zip
mv ./drush-master ./drush
echo "alias drush='~/drush/drush'" >> .bashrc
Drush should now be installed successfully. You should also install Composer to manage the dependencies, which you can do with the following commands:-
curl -sS https://getcomposer.org/installer | php
php composer.phar install