$string="
hi hello @begin i want this to extract
yes i want @end asas x x x x x zxzxax
hi hello hi hellooo
@begin i want this to extract
yes i want @end" .....

i had @replace=["replacestring1","replacestring2"....]

i need to have my string like.
$string="
hi hello @begin replacestrinjg1 @end asas x x x x x zxzxax
hi hello hi hellooo
@begin replacestring2 @end" .....