This chapter has explored the use of sequential files as a data storage and retrieval mechanism. You have learned how to open files in read, write, and append modes. You know how file pointers are used to refer to a file. You have written data to a file and loaded data from a file with appropriate functions. You have learned how to load an entire file into an array. You can examine a directory and determine which files are in the directory. You've learned how to use basic regular expressions in the preg_greq() function to display a subset of files in the directory. Finally, you've put all this together in a multi-program system that allows multiple levels of access to an interesting data set. You should be proud of your accomplishments.