A number of things can be accomplished with it. This documentation excerpt indicates the capabilities: Quick summary of the parameters/tools: -infile file that is used for input, where applicable -outfile file that is used for processed output, where applicable -record_type whatever you're doing, look only at the specified record type -manual_edit process infile to enable editing via any text editor -finish_manual_edit convert manually edited file back to MARC format -create_filters selectively process input based on field/subfield/indicators -filter_file switch from standard to specified filter file, or turn filter off -create_actions for leader, any field/subfields: add|delete|copy|relabel|replace -delete_action remove an action from standard actions file -use_action apply the specified action -update005 optionally update 005 when an action changes a record -action_file switch from standard to specified action file -no_actions absolutely do not do anything with any actions -create_ctl_file store parameters for easy reuse of a common application -use_ctl_file specifying this parameter invokes the stored parameters -output_edits_only output only those records changed by an action -dryrun do an action run-through without changing anything -progress real-time progress indicator suitable for larger files -segregate split infile into separate files of bibs, holdings, authorities -dupe_finder find field duplication within a record -get_field prints all occurrences of the specified field to STDOUT -field_sifter output records containing (or not) the specified field It is available at: https://royzimmer.library.wmich.edu/marc_index.html As it is a Perl program it does require Perl on your system and that's all it needs.