Beancount, software written by the author of the parent piece, is a terrific "plain text" double entry accounting system. I've used it for more than a decade on

Beancount, software written by the author of the parent piece, is a terrific "plain text" double entry accounting system. I've used it for more than a decade on both personal finances and non-profit treasury projects. It was many tools in its ecosystem for reformatting (single entry) transactions into double entry.