Сед добавить линию после матча
sed -i '/pattern to match/a line_to_add_after_after_the_line_matched' file
Clever Cod3
sed -i '/pattern to match/a line_to_add_after_after_the_line_matched' file
sed '/^anothervalue=.*/a after=me' test.txt
sed -i '/pettern to match/a line_to_add_after_after_the_line_matched' file