How do I edit the 856 field in Safari MARC records?
This requires a MARC Edit, which can be downloaded from http://marcedit.reeset.net/downloads
This will convert all the MARC files into the .txt file. You will want to open that file and do a find and replace with the proxied URL. An initial 856 field looks like below. The $u is extremely important so be careful with your find and replace.
=856 4\$zConnect to this resource online$uhttp://proquestcombo.safaribooksonline.com/?uiCode=pqtsbs&xmlId=9780321619686
Once everything is setup properly, you will want to convert them back to MRC file again. To do this: