#!/bin/bash
s='import "aaaa/bbbb.ccc";
import "dddd/eeee.ccc";
import "fffff/ggg/hhhh.ccc";
BLBLBL
BL2BL2BL'
sed -E 's,^(import ").*/,\1ooooo/,' <<< "$s"
IyEvYmluL2Jhc2gKcz0naW1wb3J0ICJhYWFhL2JiYmIuY2NjIjsKaW1wb3J0ICJkZGRkL2VlZWUuY2NjIjsKaW1wb3J0ICJmZmZmZi9nZ2cvaGhoaC5jY2MiOwoKQkxCTEJMCkJMMkJMMkJMJwpzZWQgLUUgJ3MsXihpbXBvcnQgIikuKi8sXDFvb29vby8sJyA8PDwgIiRzIg==