exit function crashes with sed error

[max-baz]

This line:

https://github.com/dsanson/termpdf/blob/5d9e9796d618dbe81bace9ffeb65f409cb461cb4/termpdf#L362

Crashes with:

sed: -e expression #1, char 1: unknown command: `.'

I'm guessing instead of -i '.bak' it should be -i.bak.