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PCBASIC(1) General Commands Manual PCBASIC(1)


pcbasic - A free, cross-platform emulator for the GW-BASIC family of interpreters.


PC-BASIC is a free, cross-platform interpreter for GW-BASIC, Advanced BASIC (BASICA), PCjr Cartridge Basic and Tandy 1000 GWBASIC. It interprets these BASIC dialects with a high degree of accuracy, aiming for bug-for-bug compatibility. PC-BASIC emulates the most common video and audio hardware on which these BASICs used to run. PC-BASIC runs plain-text, tokenised and protected .BAS files. It implements floating-point arithmetic in the Microsoft Binary Format (MBF) and can therefore read and write binary data files created by GW-BASIC.


pcbasic [program|package [output]] [OPTION] ...


Positional arguments must come before any options, must not start with a dash -. Any positional arguments that follow options will be ignored.

If a .BAS program is specified as the first positional argument, it will be run. The --run, --load and --convert options override this behaviour.

If a zipfile package or directory is specified as the first positional argument, any contained configuration file PCBASIC.INI will be loaded; usually, it will run a program file in the package. All other command-line options will override the package configuration file, note in particular the potential of the --run, --load and --convert options to alter the behaviour of the package.

If a second positional argument is specified, it sets the output file for file format conversion. This argument is ignored unless the --convert option is given.


Allow programs to POKE into code memory.

Set the display aspect ratio to x:y. Only has an effect if combined with --interface=graphical.

Use the command-line interface. This is identical to --interface=cli.

Set the width of the screen border as a percentage from 0—100. The percentage refers to the total width of the borders on both sides as a fraction of the usable screen width. Only has an effect if combined with --interface=graphical.

Set the title bar caption of the PC-BASIC window. Default title is PC-BASIC.

Attach a resource to the CAS1: cassette device. type:value can be

WAV:wav_file Connect to the RIFF Wave file wav_file with data modulated in IBM PC cassette format.

CAS:cas_file Connect to the PCE/PC-BASIC CAS tape image cas_file.

Load the specified codepage. The codepage determines which characters are associated to a given character byte or, in the case of double-byte codepages, two character bytes. The available codepages are stored in the codepage/ directory; by default, these are: 437 720 737 775 806 850 851 852 853 855 856 857 858 860 861 862 863 864 865 866 868 869 874 932 934 936 938 949 950 1258 alternativnyj armscii8a big5-2003 big5-hkscs georgian-academy georgian-ps iransystem iscii-as iscii-be iscii-de iscii-gu iscii-ka iscii-ma iscii-or iscii-pa iscii-ta iscii-te kamenicky koi8-r koi8-ru koi8-u mazovia mik osnovnoj pascii ruscii russup3 russup4ac russup4na viscii . See the list of codepages in the User's Guide for details. The specifier nobox disables box-drawing recognition for double-byte character set code pages. By default, sequences of box-drawing characters are recognised by an algorithm that isn't as smart as it thinks it is, and displayed as box drawing rather than as DBCS characters. If nobox is set, they will be displayed as DBCS.

Read a configuration file. The system default configuration is always read first, but any preset group of options in a configuration file replaces the whole equivalent default preset group.

Attach a resource to the COM1: serial device. type:value can be one of the following.

PORT:device_name Connect to a serial device. device_name can be a device name such as COM1 or /dev/ttyS0 or a number, where the first serial port is number 0.

SOCKET:host:socket Connect to a TCP socket on a remote or local host.

RFC2217:host:socket Connect using the RFC2217 protocol to a TCP socket on a remote or local host.

STDIO:[CRLF] Connect to standard I/O of the calling shell. If CRLF is specified, PC-BASIC replaces CR characters with LF on its output and LF with CR on its input. This is more intuitive on Unix shells. When using a Unix console, you should use stty -icanon to enable PC-BASIC to read input correctly.

If this option is not specified, the COM1: device is unavailable.

Attach a resource to the COM2: serial device. See --com1.

Convert program to one of the following formats:

A Plain text

B Tokenised

P Protected

If output is not specified, write to standard output. If program is not specified, use the argument of --run or --load. If none of those are given, read from standard input. Overrides --resume, --run and --load.

Enable clipboard operations with the mouse. If True (default), select text with the left mouse button to copy and paste with the middle mouse button.

If False, follow GW-BASIC behaviour where Ctrl+C breaks AUTO and INPUT but not program execution or LIST. If True, treat Ctrl+C exactly like Ctrl+Break and Ctrl+Scroll Lock when --interface=graphical. With --interface={text|cli}, Ctrl+C is always treated like Ctrl+Break. Default is True.

Set the current device to the indicated PC-BASIC drive letter or CAS1 for the cassette device. The device chosen should be mounted to an actual location using --mount (or --cas1 if the cassette device is chosen).

Developer option - use only if you know what you're doing. Enable debugging extension.

Set window dimensions to x by y pixels. This overrides --scaling=native and --aspect. Only has an effect if combined with --interface=graphical.

Enable double-precision transcendental math functions. This is equivalent to the /d option in GW-BASIC.

Execute BASIC statements. The statements are executed after loading any program but before entering into direct mode or running it. Multiple statements can be entered by separating them with colons :. These will be executed as if they were entered as separate statements, not as a single compound statement; even if statements such as GOTO can be included, the following statements will be executed. If a : is intended to be part of a statement, the statement must be quoted with single quotes '. If your calling shell interprets such quotes, you should properly escape them.

Developer option - use only if you know what you're doing. Load extension module(s).

Use the specified fonts for the interface. The last fonts specified take precedence, previous ones are fallback. Default is unifont,univga,freedos (i.e. the freedos font has preference). The available fonts are stored in font/. By default, the following fonts are available: unifont univga freedos cga mda vga olivetti tandy1 tandy2 . See the list of fonts in the User's Guide for details.

Fullscreen mode. Only has an effect if combined with --interface=graphical.

Show a usage message and exit.

Disable listing and saving to plain text of lines beyond line_number, as in GW-BASIC beyond 65530. Use with care as this allows execution of hidden lines of code. Default is to list all lines.

Disable listing and saving to plain text of protected files, as in GW-BASIC. Use with care as this allows execution of hidden lines of code.

Retrieve keyboard input from input_file, except if KYBD: is read explicitly. Input from KYBD: files is always read from the keyboard, following GW-BASIC behaviour. If input_file is STDIO: or STDIN:, keyboard input will be read from standard input. If RAW is specified, input will be treated as codepage bytes. If not, it will be treated as the locale's encoding (probably UTF-8).

Choose the type of interface. Not all interfaces will be available on all systems. The following interface types may be available:

none Filter for use with pipes. Also -n.

cli Command-line interface. Also -b.

text Text interface. Also -t.

graphical Graphical interface.

sdl2 SDL2 graphical interface.

pygame PyGame graphical interface (deprecated, please use SDL2 instead).

ansi ANSI text interface.

curses NCurses text interface.

The default is graphical.

Insert the keystring into the keyboard buffer. keystring may contain escape codes such as \r for return, \n for line feed and \xXX to enter CHR$(&HXX). keystring may contain e-ASCII codes to indicate keypresses that do not have a regular character encoding. For example, \0\x0F indicates Shift+Tab.

Start in direct mode with the BASIC program loaded.

Write error and warning messages to log_file instead of stderr.

Attach a resource to the LPT1: parallel device. type:value can be

PRINTER:[printer_name][:trigger] Connect to a Windows, LPR or CUPS printer. If printer_name is not specified, the default printer is used. The printer is activated when a file open to it is closed, a program terminates or PC-BASIC exits. Note that, unlike LPT1:, printers connected to LPT2: or LPT3: do not get activated when a program terminates. If specified, trigger sets an additional trigger to activate the printer:

line After every line break.

page After every page break.

close No additional trigger

The default behaviour is that of close.

FILE:file_name Connect to any file or device such as /dev/stdout on Unix or LPT1 on Windows.

STDIO:[CRLF] Connect to standard output of the calling shell. If CRLF is specified, PC-BASIC replaces CR characters with LF on its output. This is more intuitive on Unix shells.

PARPORT:port_number Connect to a Centronics parallel port, where port_number is 0 for the first parallel port, etc. PARPORT only works with physical parallel ports; for example, a Windows printer or other device mapped with NET USE LPT1: can only be attached with FILE:LPT1

If this option is not specified, LPT1: is connected to the default printer.

Attach a resource to the LPT2: parallel device. See --lpt1. If this option is not specified, LPT2: is unavailable.

Attach a resource to the LPT3: parallel device. See --lpt1. If this option is not specified, LPT3: is unavailable.

Set maximum number of open files to number_of_files. This is equivalent to the /f option in GW-BASIC. Default is 3.

Set the maximum size of the data memory segment to max_memory and the maximum size of the data memory available to BASIC to basic_memory_blocks*16. In PC-BASIC, the minimum of these values is simply the data memory size; the two values are allowed for compatibility with the /m option in GW-BASIC.

Set maximum record length for RANDOM files to record_length. Default is 128, maximum is 32767. This is equivalent to the /s option in GW-BASIC.

Sets the monitor type to emulate. Available types are:

rgb RGB colour monitor (default).

composite Composite colour monitor.

green Green-tinted monochrome monitor.

amber Amber-tinted monochrome monitor.

grey Greyscale monochrome monitor.

mono Green-tinted monochrome monitor (same as green).

On SCREEN 2 with --video={pcjr|tandy|cga}, --monitor=composite enables (crude) colour artifacts.

Assign the path path to drive letter drive:. The path can be absolute or relative. If this option is not specified: on Windows, all Windows drive letters will be assigned to PC-BASIC drive letters; on other systems, the current working directory is assigned to Z:.

Run PC-BASIC as a command-line filter. Same as --interface=none.

Send screen output to output_file, except if SCRN: is written to explicitly. Output to SCRN: files will always be shown on the screen, as in GW-BASIC. If the specifier append is given, the output file is appended to rather than overwritten. If output_file is STDIO: or STDOUT:, screen output will be sent to standard output.

Define PEEK preset values. If defined, DEF SEG seg:? PEEK(addr) will return val.

Load machine preset options. A preset option corresponds to a section defined in a config file by a name between square brackets, like [this] --preset=this will load all settings defined in that section. Available presets depend on your configuration file. See the list of default presets in the User's Guide.

Suppress window close event. This allows BASIC to capture key combinations that normally close the window. Graphical interface only. By default, the operating system's key combination to close a window (usually Alt+F4) terminates PC-BASIC. Set --prevent-close to allow BASIC to capture this key combination instead. This is useful if your program uses this key combination.

Quit interpreter when execution stops. If combined with --run, PC-BASIC quits when the program ends. If set in direct mode, PC-BASIC quits after the first command is executed.

Reserve number_of_bytes of memory at the bottom of the data segment. For compatibility with GW-BASIC. Default is 3429 bytes. Lowering this value makes more string and variable space available for use by programs.

Resume from saved state. Overrides --run and --load.

Run the specified program. Overrides --load.

Choose scaling method.

smooth The display is smoothly scaled to the largest size that allows for the correct aspect ratio.

crisp The display is scaled to the same size as with smooth, but without smoothing.

native Scaling and aspect ratio are optimised for the display's native pixel size, without smoothing. --scaling=native overrides --aspect.

Default is smooth. Only has an effect if combined with --interface=graphical.

Set serial input buffer size. Default is 256. If set to 0, serial communications are disabled.

Enable the SHELL statement to run the operating system command interpreter shell-executable. The executable shell-executable should support MS-DOS's COMMAND.COM calling conventions, in particular its /C switch. Example command interpreters are CMD.EXE on Windows and "wine cmd.exe" on Unix. If shell-executable is empty (as it is by default), the SHELL statement is disabled.

Do not treat LF in text and program files as a line break. This enables the highest level of compatibility with GW-BASIC files. If this option is set, any Linux or Mac text files need to be converted to DOS text before using them with PC-BASIC.

Choose the sound engine to use. Not all sound engines will be available on all systems.

none Suppress sound output.

beep Use the built-in speaker.

portaudio Use the PortAudio sound generator.

interface Use the native sound engine of the interface, if available.

Default is interface.

Set the save-state file to state_file. Default is pcbasic.session in the Application Data directory.

Choose BASIC dialect. Available dialects are:

advanced Microsoft GW-BASIC and IBM BASICA

pcjr IBM PCjr Cartridge BASIC

tandy Tandy 1000 GW-BASIC.

Default is advanced.

Use text-based interface. Same as --interface=text.

Set the terminal program run by the PCjr TERM command to terminal_program. This only has an effect with --syntax={pcjr|tandy}.

Set the number of columns in text mode at startup. Default is 80.

Set the text encoding. Text files (i.e. plain-text programs and files opened for INPUT and OUTPUT) stored on a disk device will be assumed to be encoded in encoding. Examples of valid encodings are utf-8, utf-16, latin-1. Please ensure that all characters in the current codepage are included in the encoding you choose; if this is not the case then such characters will be replaced by � or ?. If encoding is not set, text files will be treated as raw bytes in the current PC-BASIC codepage.

Set the text encoding to UTF-8. This option is deprecated and ignored if --text-encoding is set. Use --text-encoding instead.

Print PC-BASIC version string and exit.

Set the video adapter to emulate. Available adapters:

vga Video Graphics Array

ega Enhanced Graphics Adapter

cga Color/Graphics Adapter

mda Monochrome Display Adapter

hercules Hercules Graphics Adapter

pcjr IBM PCjr graphics

tandy Tandy 1000 graphics

olivetti Olivetti M24 graphics

Default is vga.

Set the amount of emulated video memory available. This affects the number of video pages that can be used. On PCjr and Tandy, this can be changed at runtime through the CLEAR statement; at least 32768 needs to be available to enter SCREEN 5 and SCREEN 6. Default is 16384 or PCjr and Tandy and 262144 on other machine presets.

If True, PC-BASIC waits for a keystroke before closing the window on exit. Only works for --interface=graphical or --interface=text. Default is False.

Set GW-BASIC-style command-line switches. This is a convenience option to facilitate migration from GW-BASIC. gwbasic_options is a string that may contain the following options:

/d Enable double-precision floating-point math functions. See also --double.

/f:n Set the maximum number of open files. See also --max-files.

/s:n Set the maximum record length for RANDOM files. See also --max-reclen.

/c:n Set the size of the receive buffer for COM devices. See also --serial-buffer-size.

/i Statically allocate file control blocks and data buffer. Note that this is already the default approach in GW-BASIC and PC-BASIC so that this option has no effect.

/m:n,m Set the highest memory location to n and maximum BASIC memory size to m*16 bytes. See also --max-memory.

>filename Write screen output to filename. See also --output.

>>filename Append screen output to filename. See also --output.

<filename Read keyboard input from filename. See also --input.

GW-BASIC-style switches are not case sensitive. Note that the symbols used in these switches may have different meaning in the shell from which PC-BASIC is called; you should quote and escape the options as necessary.


Start PC-BASIC in direct mode, emulating GW-BASIC/BASICA with VGA graphics.

Start PC-BASIC using the Big-5 codepage.

Start PC-BASIC with package Foobar. Load the settings from the package; usually this will run a main program contained in the package.

List the main program of package Foobar to standard output as UTF-8.

Mount the current directory's subdirectory files as drive A: and subdirectory morefiles as drive B:, then run MYPROG.BAS.

Run PC-BASIC with Windows directory C:\fakeflop mounted as A: drive.

Run INFO.BAS in the current directory on an emulated MDA with amber tinted monitor.

Run COMP.BAS stored at /home/me/retro on an emulated CGA machine with a composite monitor.

Run PCJRGAME.BAS on an emulated PCjr and feed in the keystrokes startEnter.

Run BANNER.BAS in default mode with the default printer attached to LPT2:.

Resume the most recently closed PC-BASIC session.

Execute the BASIC command PRINT 1+1 in the command-line interface and return to the calling shell.


User configuration file. Options in this file take the form of command-line options without the preceding --. One option per line. Options added under the [pcbasic] header are loaded by default. Options added under another header will be loaded if the --preset option group of that name is loaded.

$XDG_DATA_HOME/pcbasic.session or ~/.local/share/pcbasic-2.0/pcbasic.session
Saved state of the last PC-BASIC session. Continue the last session with --resume. This file is saved in a binary storage format and not meant to be edited or exchanged.


There are no environment settings specific to PC-BASIC. However, BASIC programs may access the environment through the ENVIRON$ function and could therefore have their own environment settings.


PC-BASIC is written and maintained by Rob Hagemans <>.