Olá Guido
Acho que isso pode te ajudar, encontrei isto na documentação http://hsqldb.org/doc/guide/running-chapt.html
"The HSQLDB jar package, hsqldb.jar, is located in the /lib directory of the ZIP package and contains several components and programs.
Components of the Hsqldb jar package
HyperSQL RDBMS Engine (HSQLDB)
HyperSQL JDBC Driver
Database Manager (GUI database access tool, with Swing and AWT versions)
The HyperSQL RDBMS and JDBC Driver provide the core functionality. DatabaseManagers are general-purpose database access tools that can be used with any database engine that has a JDBC driver.
An additional jar, sqltool.jar, contains Sql Tool, command line database access tool. This is a general purpose command line database access tool that can be ued with other database engines as well."
Na pasta extraída do HSQLDB , no diretório /lib , procure um sqltool.jar para acessar via linha de comando.
Boa Sorte!
