There are several places that are calling a sub-process and its output is leaked to the terminal, when it shouldn't. - `craft_parts/packages/snaps.py` - two `check_call` calls - `craft_parts/utils/os_utils.py` - three `check_call` calls Probably they should be converted to something like the following: subprocess.run(..., stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL) Note that calling `check_output` would fix the problem anyway, but in reality if the command output is not needed, it's better to discard it directly (send it to devnull) than store it in memory and then discard it (a `check_output` call without storing the result)