What is "bagit"

BagIt is a hierarchical file packaging format designed to support disk-based storage and network transfer of arbitrary digital content. A "bag" consists of a "payload" (the arbitrary content) and "tags", which are metadata files intended to document the storage and transfer of the bag. A required tag file contains a manifest listing every file in the payload together with its corresponding checksum. The name, BagIt, is inspired by the "enclose and deposit" method, sometimes referred to as "bag it and tag it".

Bags are ideal for digital content normally kept as a collection of files. They are also well-suited to the export, for archival purposes, of content normally kept in database structures that receiving parties are unlikely to support. Relying on cross-platform ( Windows and Unix) filesystem naming conventions, a bag's payload may include any number of directories and sub-directories (folders and sub-folders). A bag can specify payload content indirectly via a "fetch.txt" file that lists URLs for content that can be fetched over the network to complete the bag; simple parallelization (e.g. running 10 instances of Wget) can exploit this feature to transfer large bags very quickly. Benefits of bags include

• Wide adoption in digital libraries (e.g., the United States' Library of Congress).
• Easy to implement using ubiquitous and ordinary filesystem tools.
• Content that originates as files need only be copied to the payload directory.
• Compared to XML wrapping, content need not be encoded (e.g. Base64) which saves time and storage space.
• Received content is ready-to-go in a familiar filesystem tree.
• Easy to implement fast network transfer by running ordinary transfer tools in parallel.