-search="Copyright \(([cC]) \)\?\(${some_year}\)\(-${some_year}\)\? ${copyright_owner}"
-replace="Copyright \1\2-${this_year} ${copyright_owner}"
-
+# sed_script:
+# for all lines that contain ${copyright} : {
+# replace years yyyy-zzzz (or year yyyy) by yyyy-${this_year}
+# replace repeated years yyyy-yyyy by yyyy
+# }
+sed_script="/${copyright}/{ s/${year_range}/\1-${this_year}/ ; s/(${some_year})-\1/\1/ }"