hi, in our uni we have installed 3 versions of houdini, 11.0 - 11.1 - 12.0. when ever I launch hbatch from shell it uses hbatch 11.0 and the same happens with hython:
Houdini 11.0.469 hou module imported.

I have a program to run simulations and rendering from shell and through the network but I want to use h12 not the older version. How can I do that?

How are you running hython? …I'm just guessing here, but instead of running ‘hython’ from the terminal try running:

/pathtohoudini12.0/bin/hython instead?

Solitude
How are you running hython? …I'm just guessing here, but instead of running ‘hython’ from the terminal try running:

/pathtohoudini12.0/bin/hython instead?

Thank you Solitude, you guessed right, i will try that!
I guess this is the same with the mantra command? Is there any env variable to set the default for any of these?

Yup, it'd be the same for mantra / hython / hbatch etc most likely. What's happening is your one version of houdini is in the search path – the $PATH variable. Look up modifying the search path (that's what $PATH is) for whatever shell you're using (likely bash or csh). Though your shell is setting it automatically somewhere – It's likely in your ~/.bash_profile, ~/.bashrc or if you are using csh it might be in ~/.cshrc. Anyways, those are my guesses.

cheers