A-Shell BASIC programs rely heavily on the use of subroutines to perform functions from the simple STRIP (strip trailing spaces from a string) to the more complex BASORT (sort sequential and random data files). In the days before A-Shell, subroutines were disk files with the extension SBR, and traditionally lived in DSK0:[7,6] (BAS:). When a program called a subroutine, it was loaded from disk if necessary, and processed from the beginning.

Subroutine handling under A-Shell is functionally identical: your program invokes a routine, and A-Shell calls to its start. With some exceptions, A-Shell subroutines do not exist as separate SBR files; they are, instead, linked into the A-Shell object module and are therefore always available.

A-Shell comes with several hundred subroutines, including nearly all of the so-called Alpha Accounting routines from [7,60] and the so-called "standard A-BASIC subroutines" from [7,6]. It also includes the most popular MicroSabio subroutines (INFLD, INMEMO, EZSPL.SBR, MSBOXX), plus a variety of routines that have been written specifically for A-Shell. In addition, A-Shell includes many third-party subroutines that have been converted over the years as more firms and developers have migrated to A-Shell.

This document lists the most commonly used routines, and provides detailed documentation for most of them. Those not listed were skipped because they are too obscure or are specific to individual users. Recently-added routines, are usually documented even if they are obscure and/or for specific users.

If there is a function that you need and do not see, be sure to inquire about it before writing your own.