check
Check for various kinds of errors in your data.

_FLAGS

hledger provides a number of built-in error checks to help prevent
problems in your data. Some of these are run automatically; or, you can
use this check command to run them on demand, with no output and a zero
exit code if all is well. Specify their names (or a prefix) as
argument(s).

Some examples:

hledger check      # basic checks
hledger check -s   # basic + strict checks
hledger check ordereddates payees  # basic + two other checks

Here are the checks currently available:

Basic checks

These checks are always run automatically, by (almost) all hledger
commands, including check:

-   parseable - data files are well-formed and can be successfully
    parsed

-   balancedwithautoconversion - all transactions are balanced,
    inferring missing amounts where necessary, and possibly converting
    commodities using transaction prices or automatically-inferred
    transaction prices

-   assertions - all balance assertions in the journal are passing.
    (This check can be disabled with -I/--ignore-assertions.)

Strict checks

These additional checks are run when the -s/--strict (strict mode) flag
is used. Or, they can be run by giving their names as arguments to
check:

-   accounts - all account names used by transactions have been declared

-   commodities - all commodity symbols used have been declared

-   balancednoautoconversion - transactions are balanced, possibly using
    explicit transaction prices but not inferred ones

Other checks

These checks can be run only by giving their names as arguments to
check. They are more specialised and not desirable for everyone,
therefore optional:

-   ordereddates - transactions are ordered by date within each file

-   payees - all payees used by transactions have been declared

-   uniqueleafnames - all account leaf names are unique

Custom checks

A few more checks are are available as separate add-on commands, in
https://github.com/simonmichael/hledger/tree/master/bin:

-   hledger-check-tagfiles - all tag values containing / (a forward
    slash) exist as file paths

-   hledger-check-fancyassertions - more complex balance assertions are
    passing

You could make similar scripts to perform your own custom checks. See:
Cookbook -> Scripting.