dos2ansi - a tool to convert MS-DOS/ANSI.SYS text files to modern terminals

This tool converts MS-DOS text files using ANSI.SYS escape sequences to a format a modern terminal can display. The output will use a Unicode encoding of characters and only ANSI SGR escape sequences to set basic foreground and background colors, intensity and blinking attribute. The input is expected to use CP-437 or one of the other supported DOS codepages.

The builtin translation tables attempt to match the appearance on VGA as close as possible. For example, unused codepoints are mapped to U+25AE (Black Vertical Rectangle), because scans of old Microsoft documents show a glyph resembling this. This is also relevant for e.g. arabic letters that have many different forms; they are translated to unicode codepoints denoting the "isolated" form, because this was the only way they could be displayed in text mode. As a consequence, this tool isn't well-suited for converting arabic text.

Results depend on both your terminal (there are interesting issues with e.g. writing direction) and the font you're using (e.g. on Windows, the "Courier New" font sometimes gives better results than "Consolas"). Please check with different terminals and fonts before reporting a bug in dos2ansi.

Install dos2ansi

Releases will contain a .tar.xz archive of the source for building yourself (which works simply with make or make strip, see Building for details) and a .zip archive containing dos2ansi compiled for Windows.

Installation is as simple as placing the binary somewhere in your path, it doesn't need any other files at runtime.

Features

• Renders to a virtual canvas with a fixed width, defaulting to 80 columns
• Supports SGR sequences as well as cursor movement sequences in the input
• Autodetecs whether any visible color is used, if not, the output won't use any escape sequences
• Supports flexible modes for color output, from simple 8-color mode with attributes for "bright" colors up to exact CGA/VGA colors using 256-color mode and more, including a terminfo (curses) based writer for unix-like systems and one using the legacy Console API for older Windows versions (pre Windows 10).
• Supports all simple control characters MS-DOS interpreted when outputting text: NUL (ignored), BEL (ignored), BS, TAB, LF, CR and ESC (ignored when it doesn't start some ANSI.SYS sequence)
• Interprets control characters not supported by MS-DOS as symbols from CP437
• Stops reading at the MS-DOS EOL character (0x1a), this can also be disabled
• Input codepage can be selected, currently supported: 437, 708, 720, 737, 775, 819, 850, 852, 855, 857, 860, 861, 862, 863, 864, 865, 869, KAM, MAZ and MIK
• Supports codepage aliases and versions with Euro sign
• Output format can be UTF-8, UTF-16 or UTF-16LE, with or without a BOM, with LF (Unix style) or CRLF (DOS/Windows style) line endings
• Optionally translates the pipe bar symbol to a broken bar, matching the appearance with most hardware fonts
• Includes a test mode rendering an encoding table with the selected settings and the color palette to verify appearance on your terminal
• Parses a subset of SAUCE metadata useful for MS-DOS text files, which is used to set some defaults (screen width, blinking mode and codepage) and can also be displayed

Test mode

SAUCE display

Building

To build dos2ansi from source, either grab and extract a release tarball or clone the repository directly from git to get the latest changes:

git clone --recurse-submodules https://github.com/Zirias/dos2ansi.git

The following is required for building:

• GNU make
• A C compiler supporting C11, either GCC or one compatible with GCC's commandline like llvm/clang.
• On "unixy" systems, a curses library (typically ncurses). This is optional, but enabled by default.

For Windows, GNU make and appropriate compilers are conveniently available from the MSYS2 distribution. If your system has a different flavor of make by default (e.g. a BSD system), GNU make will typically be installed as gmake, so type this instead of make.

To compile the tool, just type

make

To get a stripped version, type

make strip

If you want to build a version with full debugging symbols, you can use

make BUILDCFG=debug

Installing can be done with

make install

The binary is installed to $(prefix)/bin, with prefix defaulting to /usr/local. So, to install e.g. to /opt/dos2ansi/bin, you would type

make prefix=/opt/dos2ansi install

There are a few build-time configuration options available:

• STATIC: When set to a truthy value, the tool is linked statically. This is used for the official Windows binaries. Defaults to 0.
• WITH_CURSES: Use curses to build a terminfo-based output writer that will automatically respect $TERM. Only available on non-Windows, defaults to 1.
• FORCE_STDIO: Always use the standard C stdio.h functions for I/O, instead of a platform-specific backend (available are POSIX and win32). Defaults to 0.

So, make FORCE_STDIO=1 strip would build a stripped version using standard C I/O, make WITH_CURSES=no would build a version not linked to curses.