[This article was copied from the Voyager Wiki.]
This is just a quick introduction to USEMARCON.
USEMARCON is a MARC record conversion utility that can be used to manipulate MARC records according to rules. USEMARCON is a multi-platform open source C++ library and a command line program. It is especially suitable for batch processes and on-the-fly record conversions. Also a GUI front-end for Windows is available for creating the rules, running conversion and verifying the results. It can also be used just to browse records.
USEMARCON can be integrated with IndexData's YAZ Proxy making it possible to manipulate records requested via Z39.50 or SRU.
USEMARCON can read and write records in ISO2709, MARCXML and MarcXchange formats. It supports UTF-8 and can also convert MARC8 encoding to UTF-8.
USEMARCON is available from the British Library at http://www.bl.uk/bibliographic/usemarcon.html. The zip package contains a Windows command line executable in addition to the source code.
USEMARCON GUI can be downloaded directly from the National Library of Finland at http://www.kansalliskirjasto.fi/kirjastoala/formaatit/gui.html (sorry, the page is in Finnish, but the link is there in the beginning and USEMARCON GUI itself is in English).
USEMARCON is currently being maintained and developed by Ere Maijala from the National Library of Finland. Please contact Ere for more information (email: first.last at helsinki.fi).
Comment by Oren Maurer
I have also noticed that the USEMARCON command line executable - should be installed first.
The GUI is separate and it needs the full path to the command line executable.
It can be quite interesting to compare it to MarcEdit.