EN
The formats of bibliographic and item records change several times - willingly or unwillingly - in the life of a library. Even when a specific data format is preserved for decades, semantic and syntactic errors occur, not to mention data conversion errors. This can make maintenance more difficult and searches less effective. In this article the filtering of bibliographic and item records are demonstrated with the command-line filter components of the free Cinege, which has been developed in the Budapest University of Technology and Economics National Technical Information Centre and Library and was tested in the BUTE NTICL and in the Universitätsbibliothek der Freie Universität Berlin.