incremental backups.
<options> is a comma-separated list of <option> or <option>=<value>.
-The only currently support option is gz[=<compressionlevel>], to
+The only currently support options are gz[i][=<compressionlevel>], to
indicate that the whole stream should be compressed with gzip. The
-compression level defaults to 1.
+compression level defaults to 1 if gz is specified by the level isn't.
+gzi appliies only to the incrementals; gz applies to both unless gzi
+is also specified. compression level 0 means not to run gzip at all
+and is the default if gz[i] is not mentioned.
expected-diffs is a config file to indicate which
filesystems should *not* be backed up. The scripts do a config