diff\
Compares a particular account's transactions in two input files.
It shows any transactions to this account which are in one file but
not in the other.

More precisely, for each posting affecting this account in either
file, it looks for a corresponding posting in the other file which
posts the same amount to the same account (ignoring date, description,
etc.) Since postings not transactions are compared, this also works
when multiple bank transactions have been combined into a single
journal entry.

This is useful eg if you have downloaded an account's transactions
from your bank (eg as CSV data). When hledger and your bank disagree
about the account balance, you can compare the bank data with your
journal to find out the cause. 

$FLAGS$

Examples:

```shell
$ hledger diff -f $LEDGER_FILE -f bank.csv assets:bank:giro 
These transactions are in the first file only:

2014/01/01 Opening Balances
    assets:bank:giro              EUR ...
    ...
    equity:opening balances       EUR -...

These transactions are in the second file only:
```
