On Ubuntu, I get:

export id=a
export tools=gcc-4.8

tomkent@todd08:~/teeks99-09test/a$ python run.py
--runner=teeks99-09${id}-Ubuntu12.04-64 --toolsets=${tools}
--force-update --bjam-options=-j2 --comment=../info.html 2>&1 | tee
output.log
# Running regressions in /home/tomkent/teeks99-09test/a...

# Creating regression scripts at

/home/tomkent/teeks99-09test/a/tools_regression_src...

# Dowloading regression scripts from
https://raw.github.com/boostorg/boost/develop/tools/regression/src...
# Getting Boost.Build v2...

error: unknown option `single-branch'