From the omnidb manual page:

-filesearch [-n N] ClientName DirectoryPath FileName

 Lists all the backed up files and directories that match the selection criteria set by the ClientName DirectoryPath FileName parameters. Wildcards can be used. The list can be limited to a certain number of displayed objects by setting the -n option, where N is the number of objects to be displayed. The following information is displayed about each object: object type, object name, object description, pathname.Note: DirectoryPath can be a complete or incomplete path. For example for file C:\Directory\Sub-directory\file.txt , DirectoryPath can be /, /Directory/ or /Directory/Sub-directory.

There are a couple of things to note to make use of this option successfully.

• DirectoryPath can be a complete or incomplete as indicated in the man page. But note that wildcards cannot be applied here and the start of the path must always be correct (Anything after the start can be left away)
• On Windows, the drive letter is not part of the path. So the path is always starting with / or \
• There is no difference between / and \ . Both can be used on Windows as well as on *UX and have the same meaning
• The DirectoryPath search term is case sensitive, the FileName search term is not
• The * wildcard is applied before and after the FileName search term by default if no wildcards are used. So any part of the FileName will work
• If a wildcard is used in the middle then it (wildcard) also needs to be specified at the start and the end (if start or end of name are incomplete)

You may be interested to some of my other Support Tips too: Support Tips listed per category.