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# Glossary

**persistent:** Pertaining to a program that runs indefinitely and keeps at least some of its data in permanent storage.

**format operator:** An operator, `%`, that takes a format string and a tuple and generates a string that includes the elements of the tuple formatted as specified by the format string. 

**format string:** A string, used with the format operator, that contains format sequences.

**format sequence:** A sequence of characters in a format string, like `%d`, that specifies how a value should be formatted. 

**text file:** A sequence of characters stored in permanent storage like a hard drive. 

**directory:** A named collection of files, also called a folder. 

**path:** A string that identifies a file.

**relative path:** A path that starts from the current directory. 

**absolute path:** A path that starts from the topmost directory in the file system.