"This is one of the oldest Linux accounting/ERP systems.
SQL-Ledger is a double-entry accounting system that has an amazing
list of features, such as accounts receivable, accounts payable,
voucher system, general ledger, inventory control, billing, time
cards, POS, check printing, purchase/sales orders, taxes,
multi-user/company, audit control, SQL server backend, templates,
customers, vendors, chart of accounts, and financial statements.
SQL-Ledger is often considered the “best of” for Linux