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*******             Processing include and exclude options              *******
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The user may define ID inclusion and exclusion lists. Each element represents
an ID4 or an ID6. Discs with an ID in the exclusion list are ignored (not
added, extracted, removed or listed). If --include or --include-path is used,
only discs in the include list are processed.

The include list is controlled by the to options --include and --include-path
and the exclude list by the options --exclude and --exclude-path. All four
options can be used multiple times. The exclude list ha a higher priority
as the include list.

 -n --include id     Include oly discs with given ID4 or ID6 from operation.
 -n --include @file  Read include list from file.

 -N --include-path file_or_dir
                     ISO file or base of directory tree -> scan their ID6

 -x --exclude id     Exclude discs with given ID4 or ID6 from operation.
 -x --exclude @file  Read exclude list from file.

 -X --exclude-path file_or_dir
                     ISO file or base of directory tree -> scan their ID6

The parameters of --include and --exclude are scanned for ID6. Th section
"Processing ID6 parameters" describes this scanning in detail.

The parameter of --include-path and --exclude-path is a filename or a
directory name. The given file or each file of the directory tree (recurse,
max depth=15) are scanned. Subdirectories beginning with a dot ('.') are
ignored. If a file exists and is an ISO file the ID6 is extracted and inserted
into the include or exclude data base.

Example:

 You want to make a backup from all new discs of 2 USB drives. The new
 backups should be stored info the sub directory 'new-backup'. The existing
 backups are stored in 'old-backup'. The file names of the old backups does
 not matter:

 # wwt extract -aA --dest new-backup --exclude-path old-backup

The command 'EXCLUDE' use the options --exclude and --exclude-path to builtd
the exclude data base and prints the result to stdout.