cd $HOME

tar xvjf civix-X.Y.Z.tar.bz2
mv civix-X.Y.Z civix

# Add civix to the PATH; consider updating ~/.bashrc or ~/.profile
export PATH=$HOME/civix:$PATH

cd $HOME

# If you haven't already, install the PHP tool "composer"
curl -s http://getcomposer.org/installer | php

# Download civix and dependencies
git clone git://github.com/totten/civix.git
cd civix
php $HOME/composer.phar install

# Add civix to the PATH; consider updating ~/.bashrc or ~/.profile
export PATH=$HOME/civix:$PATH

# Install composer
In a browser, visit http://getcomposer.org
Click on the download button.
Scroll down to Windows Installer and click on Composer-Setup.exe.
Choose Run when prompted.

# Install git
If you don't already have git, then in a browser visit http://git-scm.com/download/win.
Choose Run when prompted.
Leave all the defaults.

# Download civix
Decide where you want to install civix. You might want to put it in C:\Program Files, but you might get hassled about admin rights, in which case you can pick somewhere else, like C:\users\<your name>.
From the start menu choose All Programs -> Git -> Git Bash.
In the window that appears, type:
  cd "/c/users/<your name>"
  (note the forward slashes)
git clone git://github.com/totten/civix.git
exit

# Download dependencies
In windows explorer, navigate to C:\users\<your name> (or whereever you installed civix).
Shift-right-click on the civix folder.
Choose open command window here.
In the window that appears, type:
  composer install

# Add civix to the PATH
Either temporarily add it:
set PATH=%PATH%;C:\users\<your name>\civix

OR permanently:
Start Menu -> Control Panel -> System -> Advanced -> Environment Variables

cd $HOME/civix
git pull
php $HOME/composer.phar install

php $HOME/composer.phar self-update
cd $HOME/civix
git pull
rm -rf vendor
php $HOME/composer.phar install

civix generate:page --help