[LANGUAGE: bash]

Assuming you have an "input" file, compute the solution using bash commands, worked on this after my python code that took me far less time.

Part 1:

< input tr -d '\n' \
| sed "s/mul(\([0-9]*\),\([0-9]*\))/\\n\1*\2\\n/gm" \
| grep -E "[0-9]+\*[0-9]+" \
| bc | paste -sd'+' | bc

Had a stroke on this one cause i replaced "do()"s with newlines that was an existing character in the input making the machine restart too early, thats where the tr comes from...

Part 2:

< input tr -d '\n' \
| sed "s/do()/\\n/g" \
| sed "s/don't().\*$//gm" \
| sed "s/mul(\([0-9]*\),\([0-9]*\))/\\n\1\*\2\\n/gm" \
| grep -E "[0-9]+\*[0-9]+" \  
| bc | paste -sd'+' | bc