AliBuild with Ubuntu 18.04

After months of good work with my aliceO2 on Ubuntu 18.04, I recently made a git pull on both my alidist and 02. Following new requirements, I have got Python3 and new aliBuild on my laptop.
The results are not fine, see below:

manso@clralicepo09:~/aliceO2$ aliBuild build O2 --defaults o2
Traceback (most recent call last):
File “/home/manso/.local/bin/aliBuild”, line 13, in
from alibuild_helpers.args import doParseArgs
File “/home/manso/.local/lib/python2.7/site-packages/alibuild_helpers/”, line 2, in
from alibuild_helpers.utilities import format, detectArch
File “/home/manso/.local/lib/python2.7/site-packages/alibuild_helpers/”, line 23, in
from alibuild_helpers.git import git
File “/home/manso/.local/lib/python2.7/site-packages/alibuild_helpers/”, line 29
def exec(self, *args, **kwargs):
SyntaxError: invalid syntax

I tried older version of aliBuild without any success (error when building Phyton-modules-list).


Hi @manso, you are using Python 2 to run aliBuild. This does not work. Please use Python 3.

Please uninstall alibuild using “pip” and use the PPA instead, as described under “Installing aliBuild” here:

If you cannot use the PPA, then first uninstall aliBuild using pip, then reinstall it using “pip3”. That ensures the correct python version is used.

Not clear that I had to use pip3 instead of pip in the documentation. I though that the latest version of aliBuild directly uses Python3; which is installed on my laptop. In , they said “pip install alibuild”, or in the 🧪 Installation via alibuild · ALICE Analysis Tutorial, “pip install alibuild --upgrade --user”.
So fine, after one night of compilation (!), I will see if all will be ok.

Good point, thanks, I’ll update those instructions.

Thanks a lot for you careful help, I succeed to compile o2 after some issues related to capstone, upfully solved after a new git pull.
Ubuntu 18.04 is still in life!

HI Frank, Timo,
I managed to get o2 compiled and running in Ubuntu 20.04.6 LTS, if there are more checks needed please also point and lets discuss.
best regards

Thanks Debashish, good point!