Note: This section is work in progress and not complete at the moment.
Beside the GitHub releases and the developer checkout from GitHub, you can always grep the latest version of PHP_Depend from this website as a simple, single PHAR archive.
~ $ wget https://pdepend.org/static/latest/pdepend.phar
..
~ $ chmod +x pdepend.phar
That's it. Now you have a running version of PHP_Depend, that can be called on the command-line:
~ $ ./pdepend.phar --summary-xml=/tmp/sum.xml /path/to/code