While exiftool (one of the best tools in metadata space) can be used to extract metadata for doc/ppt/xls or odt/odf/ods files, it does not support writing/modifying metadata for these document types.
Is there a command-line tool or python library that allows writing metadata on text documents, presentations and spreadsheets?
It is important that metadata should be written on file level and not on file-system level so that metadata is maintained even when files are transferred between systems.
ExifTool is a platform-independent Perl library plus a command-line application for reading, writing and editing meta information in a wide variety of files. See here!
But exif-tool only applies to images for other file types you need something specific to the file type so you need to specify the exact file type.
To quote wikipedea:
Exchangeable image file format (Exif, often incorrectly EXIF) is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras (including smartphones), scanners and other systems handling image and sound files recorded by digital cameras.
Documents, Spreadsheets, Presentations, etc., all can contain metadata but the data contained and the the method of storage are usually specific to the software that created them, and in some cases specific to the exact version of the software, (e.g. most Microsoft products have changed the metadata content and format over the years).
