========
listamsb
========

------------------------------------------------------------
List the source of a tokenized Atari Microsoft BASIC program
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.. include:: manhdr.rst

SYNOPSIS
========

listamsb [**-l**] | [**-C**] | [**-D**] | [[**-a**\] [**-c**] [**-v**\] [**-h**\] [**-i**\] [**-u**\] [**-t**\] [**-m**\] [**-n**\] [**-s**\] ...] [**-r** *line-range*] [**input-file**\] [**output-file**\]

DESCRIPTION
===========

**listamsb** acts like the *LIST* command in Atari Microsoft BASIC. It reads a
tokenized (SAVEd) AMSB program and prints the code in human-readable
format.

By default, output is piped to **a8cat**\(1), which converts the
ATASCII output to something that's human-readable on modern terminals.
This means **a8cat** must be available somewhere in **$PATH**\.

**listamsb** supports both versions of Atari Microsoft BASIC: the
disk-based version 1 and the cartridge-based version 2. The language
is the same for both versions, so there's no need to specify it.

**input-file** must be a tokenized AMSB program. If no **input-file** is given,
input is read from **stdin**.

Programs created with *SAVE "filename" LOCK* are autodetected,
and will be listed normally. It's also possible to convert a LOCKed
program to an unencrypted one, with the **-l** option.

Programs can be "crunched" and "decrunched" with the **-C** and **-D**
options.

If no **output-file** is given, output is to **stdout**.

OPTIONS
=======

**-a**
  Output raw ATASCII. This option must be used with an
  **output-file**, a pipe, or redirection: **listamsb** will not write
  ATASCII to a terminal. **a8cat** is not used, with this option.

**-c**
  Check only. No output on stdout. Diagnostics are still printed on stderr,
  and the exit status is unchanged. It's an error to give an **output-file** with
  this option.

**-C**
  "Crunch" program: remove comments and spaces that occur outside of a
  string. The resulting program is usually 5 to 10 percent smaller, and
  will RUN correctly, but will be difficult to edit in AMSB because its
  parser requires the spaces. Also, if any comment-only lines are the
  target of GOTO or GOSUB, the program won't run because all comment-only
  lines are removed.

  This option must be used with an **output-file**, since seeking is done.
  None of the other options have any effect with **-C**.

**-D**
  "Decrunch" a crunched program. Puts spaces where they're required for
  AMSB's parser. The result will be editable in AMSB. Of course, any
  comments that were removed during crunching will not magically be
  retored (they're gone).

  This option must be used with an **output-file**, since seeking is done.
  None of the other options have any effect with **-D**.

**-r** *line-range*
  Show only part of the listing. *line-range* can be a single line, or
  a comma- or hyphen-separated pair of starting and ending line numbers (e.g. **100,200**, or
  **1000-2000**).

  If the start line number is omitted (e.g. **,100**), it will be treated as
  **0** (meaning, list from the beginning of the program). If the ending line
  number is omitted (e.g. **100,**), it means "list until the end of the program".
  **-r,** or **-r-** is equivalent to not using the **-r** option at all.

**-l**
  "Lock" or "unlock" the program. Locked programs are created with
  *SAVE "filename" LOCK*. The "encryption" is a reciprocal cipher: locking and
  unlocking are the same operation (similar to ROT13). The output will
  be the locked or unlocked tokenized program (rather than a listing).

  This option must be used with an **output-file**, a pipe, or
  redirection: **listamsb** will not write tokenized BASIC to a
  terminal. **a8cat** is not used, with this option.  None of the
  other options have any effect with **-l**.

**-n**
  No empty line. By default, **listamsb** prints an empty line at the
  start of the output, to match AMSB's LIST command.

**-v**
  Verbose output, on **stderr**. May be given twice for extra verbosity,
  which shows each line number, its offset, length, and end-of-line pointer.

**-h**\, **--help**
  Print built-in help and exit.

**--version**
  Print version number and exit.

**-i**\, **-u**\, **-t**\, **-m**\, **-s**
  These options are passed to **a8cat**. See its man page for details. If
  any of the **-a**, **-c**, or **-l** options are used, these options have no effect.

DIAGNOSTICS
===========

All error and warning messages are written to the standard error output.

Fatal errors
------------

These are errors in the program header at the start of the file. They
generally mean the input isn't actually an tokenized Atari Microsoft
BASIC file.

- not an AMSB file: first byte not $00 or $01

  Pretty self-explanatory: if the file doesn't begin with a *$00* or
  *$01* byte, it's not a tokenized AMSB file.

- not an AMSB file: too big (*N* bytes), won't fit in Atari memory

  The file can't be a tokenized AMSB file because there was no way
  for it to be created. It must be some other kind of file that begins
  with a *$00* byte.

- not an AMSB file: program size too small (*N*). Atari BASIC file?

  The program header claims the file is 0, 1, 3, or 4 bytes long. This
  is impossible, so this isn't an AMSB file. A lot of Atari BASIC
  programs begin with three *$00* bytes, so that might be what this is.

- program length is 2, no code in file (SAVE after NEW)

  Probably, someone did a SAVE when there was no program in memory. It
  could also mean this isn't an AMSB file at all.

Warnings
--------

These are non-fatal: **listamsb** logs the warning to stderr, then
continues processing.

- unexpected EOF, file truncated?

  A tokenized AMSB file always ends with three null bytes (*$00*\).
  This file doesn't. Probably the rest of the file is missing.

- line *L*: EOL address *A* too (low|high)

  Each line begins with the address of the next line. If the address
  is below *$0700*, it's below the minimum value of *MEMLO*, which
  is impossible. If it's above *$bc1f*, it would be in the display
  list, screen memory, or OS ROM (also impossible). File is
  corrupt, or not an AMSB file.

- line *L*: EOL address *A* <= previous *B*

  Corrupt file, or not an AMSB file.

- line *L* is suspiciously long

  The line is >128 bytes long, but less than 256. AMSB can execute
  lines of this length, but it's impossible to actually enter them
  in the editor, because a logical line can't be longer than 3
  screen lines. Possibly corrupted file.

- line *L* is impossibly long

  The line is >= 256 bytes long. AMSB will crash, if you try to
  LOAD the file. Corrupted file.

- line *L* EOL address doesn't match actual line length *N*

  Corrupt file, or not an AMSB file.

- line number out of order

  Corrupt file, or not an AMSB file.

- line number out range

  The program contains a line number that's greater than *63999*. How
  did that happen?

- line *L* has character *C* outside of a string. maybe Atari BASIC?

  This happens when ATASCII codes 0 to 31 (*$1f*\) appear in the program.
  AMSB can create files like this, but at runtime, it's a syntax error.
  More likely, it means this is an Atari BASIC file.

- program size doesn't match size in header

  Might mean this isn't an AMSB file. If you're sure it is, it might
  be truncated, or part of the file might have been overwritten with
  *$00* bytes. It could also mean the length in the header has somehow
  gotten corrupted.

- trailing garbage at end of file

  Might mean this isn't an AMSB file. If you're sure it is, garbage
  data has somehow gotten appended to the file, after the three *$00*
  bytes that end the program. Maybe it was downloaded with a crappy
  version of XMODEM that pads the last block. The good news is,
  AMSB will just ignore the garbage when you LOAD the file, so it
  won't hurt anything.

- file has *N* unknown tokens

  Either the file is corrupt, or this is a file from some *other* variant
  of Microsoft BASIC (e.g. Commodore, AppleSoft, GW-BASIC, TRS-80). If
  you see this warning, you'll also see *N* <unknown token *XX*>
  messages in the actual listing.

ENVIRONMENT
===========

**A8CAT**

  The path to the **a8cat**\(1) binary. Can be a full path or just
  the executable name, in which case it will be searched for with the
  normal **PATH** mechanism. If not set, *a8cat* is used. If there are
  spaces or other metacharacters, they must be escaped.

LIMITATIONS
===========

Unlike **listbas**, there's no color syntax highlighting. Probably there
never will be.

It's hard to reliably detect AMSB files. Most of the time, it can at least
detect Atari BASIC files, but occasionally you'll get gibberish output instead.

EXIT STATUS
===========

0 for success, 1 if there was an error reading the input (e.g. file
not found), or 2 if the input file had errors or warnings (see
**DIAGNOSTICS**).

.. include:: manftr.rst
