A few weeks ago, we talked about the problem of validating MARC records and the fact that no PHP library existed to handle this. Ted Lawless pointed out a Perl module that handles the task, and I took the time to port the code over to PHP. Now, thanks to Dan Scott, my ported code is part of the File_MARC PEAR library as of release 0.7.1:
To take advantage of this, you just need to upgrade File_MARC and install the new Validate_ISPN dependency.
Once the library is installed, you just create a File_MARC_Lint object and call its checkRecord() method against a File_MARC object to get an array of warning messages.
When I'm less busy, I'll try to find time to write a command-line script that uses this to validate files of MARC records. If somebody else cares to do so in the meantime, feel free to post it to JIRA and I'll get it into the trunk.
Let me know if you have questions or problems!