This may save someone's time.

If you get an error like this when running ./bin/buildout:

bash: bin/buildout: /home/mustapha/workspace/collective.buildbot/test/parts/buildslave/customer.pr: bad interpreter: Permission denied

Pay attention: the full path to the used python is truncated here.

that means that the shebang line (the first line in the bin/buildout script starting with #!) is too long. The maximum length of a shebang line is system dependent. On my Ubuntu the maximum length is 80. This table lists the maximum length of the shebang line per OS