Thanks for the answer! If there is only one field 856 in the record, then the "Copy and replace" template works. Does not work if there is more than one field 856 in the record. For example: 856 4 _uhttps://doi.org/10.54835/18102883_2022_31_10 856 4 _uhttps://aeer.ru/files/io/m31/art_10.pdf Template: Copy and replace field 856$u to 856$u using RegEx s/://aeer.ru//://old.aeer.ru// if 856$u matches RegEx m/://aeer.ru// Output: 856 4 _uhttps://old.aeer.ru/files/io/m31/art_10.pdf 856 4 _uhttps://old.aeer.ru/files/io/m31/art_10.pdf Am I doing something wrong? -----Original Message----- From: Koha <koha-bounces@lists.katipo.co.nz> On Behalf Of Eric Phetteplace Sent: Wednesday, May 21, 2025 1:00 AM To: Koha <koha@lists.katipo.co.nz> Subject: Re: [Koha] MARC modification templates Hi Igor, Use a regular expression in a copy and replace action in a modification template. The documentation you linked to has an example if you scroll down (see "You could also use regular expressions to add your library’s proxy URL in front of links in your MARC record."). Note that if you have multiple 856 fields in a record the templates may struggle to process both, or at least I have found that sometimes I need to bulk modify records with pymarc or MarcEdit outside Koha in these instances. Best, ERIC PHETTEPLACE Systems Librarian, Libraries (he/him) ephetteplace@cca.edu *CCA is situated on the traditional unceded lands of the **Chochenyo and Ramaytush Ohlone** peoples.* Black-owned bookstores in Oakland: Ashay by the Bay <https://ashaybythebay.com/>, Marcus Books <https://www.facebook.com/marcus.books/> :(){ :|: & };: _______________________________________________ Koha mailing list http://koha-community.org Koha@lists.katipo.co.nz Unsubscribe: https://lists.katipo.co.nz/mailman/listinfo/koha