I need to edit a link in all posts is it possible?

Hello,

I have inserted an affiliate link in all 150 posts on my blog, the link is the same in all of them. Is it possible some way to edit all the 150 links at once? the post has the link somewhere at the header of the post and one link at the top of the read more.. Is it possible to make a template or something so all posts have the links in the same place?

Thanks in advance.