You can set variables from a bash script if you just source it. But the houdini.env file doesn't exactly contain shell commands.
In bash you could do something like this:
$(cat houdini.env | grep -v "#" | grep "=" | xargs -L1 echo export)
grep -v “#” just filters out comment lines
grep “=” filters for lines actually containing an assigment
xargs -L1 echo export just prints each line with “export” prepended.
So you get output like
export HOUDINI_NO_SPLASH=1
Wrapping the whole command in $() will execute the whole thing as a shell command.
Bash also requires that there's no space around the =. Just make sure of that in your file, I didn't take care of that in the one-liner.