Item Update is a batch-mode command-line tool for altering the metadata and bitstream content of existing items in a DSpace instance.
It is a companion tool to Item Import and uses the DSpace simple archive format to specify changes in metadata and bitstream contents.
For bitstreams, 'add' and 'delete' are similarly available.
All these actions can be combined in a single batch run.
Item Update supports an undo feature for all actions except bitstream deletion. However, unlike Item Import, there is no resume feature for incomplete processing.
There is more extensive logging with a summary statement at the end with counts of successful and unsuccessful items processed.
One probable scenario for using this tool is where there is an external primary data source for which the DSpace instance is a secondary or down-stream system.