monitor changes to (configuration) files

 A program to automatically monitor changes to a set of files. If
 files are modified one day, and the machine stops working correctly
 some days later, changetrack provides information on which files were
 modified, and thus helps locate the problem. If you tell changetrack
 to use either the line editor ed (the default) or The Revision
 Control System (RCS), you can recover files to any previous stage.
 If you do not want to install Perl, try out the filetraq or diffmon
 package. Another similar program is etckeeper.