import
Read new transactions added to each FILE since last run, and add them to
the main journal file. Or with --dry-run, just print the transactions
that would be added.

_FLAGS_

The input files are specified as arguments - no need to write -f before
each one. So eg to add new transactions from all CSV files to the main
journal, it's just: hledger import *.csv

New transactions are detected in the same way as print --new: by
assuming transactions are always added to the input files in increasing
date order, and by saving .latest.FILE state files.

The --dry-run output is in journal format, so you can filter it, eg to
see only uncategorised transactions:

$ hledger import --dry ... | hledger -f- print unknown --ignore-assertions