I just did this for myself, and a quick Google search told me that apparently no one knows how to do this properly :P so maybe this will help someone. It’s possible to redirect all your links from your old tumblr link to your new tumblr link (assuming you saved your old URL). This isn’t just redirecting to your new tumblr’s homepage.
This is like if you were linked to:
and the URL automatically changes to:
(try it!) If you’ve ever tried to find a post off someone’s old url, you know how annoying it can be to track down the post in the new url.
How to use: Just add this script either before your end body tag (</body>) or in the head section (<head></head>) of the tumblr where you saved your old URL. Change oddhour.tumblr.com to whatever your new URL is.
//redirect to new blog
var path = window.location.pathname;
window.location.replace('http://oddhour.tumblr.com' + path);