Convenience functions and classes for files and filenames/pathnames.

• Pathname: subclass of str with convenience properties useful for pathnames

• BackedFile: a RawIOBase implementation that uses a backing file for initial data and writes new data to a front file

• SharedAppendFile: a base class to share a modifiable file between multiple users

• SharedAppendLines: a subclass of SharedAppendFile which shares updates in units oftext lines

• FileState: a signature object for a file state derived from os.stat or os.lstat or os.fstat; has .mtime, .size, .dev and .ino attributes

• Tee: an output file-like object for copying data to multiple output files

• abspath_from_file: restore relative path with respect to another path, as for an include filename

• chunks_of: generator yielding text or data from an open file until EOF

• lines_of: generator yielding lines of text from an open file until EOF

• compare: compare two filenames or file-like objects for content equality

• @file_property: decorator for a caching property whose value is recomputed if the file changes

• make_file_property: constructor for variants on @file_property

• @files_property: decorator for a caching property whose value is recomputed if any of a set of files changes

• make_files_property: constructor for variants on @files_property

• lockfile: context manager to take a lock file around an operation, such as access to a shared file

• shortpath: return path with the first matching leading prefix replaced with short form such as “~/” or “$LOGDIR/” etc

• longpath: the inverse of shortpath

• mkdirn: create a new directory named path+sep+n, where n exceeds any name already present

• poll_file: watch a file for modification by polling its state as obtained by FileState

• rewrite: rewrite the content of a file if changed; with an assortment of modes

• rewrite_cmgr: a context manager made from rewrite()