hledger-diff is a simple tool to compare two journal files as used with hledger. It looks at the transactions of a single account and prints out the transactions which are in one journal file but not in the other. This is particularly useful for reconciling existing journals with bank statements.
cabal install hledger-diff
» hledger-diff assets:bank:giro 2014.journal bank.journal
Unmatched transactions in the first journal:
2014/01/01 Opening Balances
assets:bank:giro EUR ...
...
equity:opening balances EUR -...
Unmatched transactions in the second journal: