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Tool to allow use of legacy IBM symbol sets #1504
Description
This is NOT a bug, but a note to inform people about a tool that works with NetHack since version 3.4 and has been tested with version 3.7. It allows the use of symbol sets that use the IBM CP437 code page and some other symbol sets on modern UTF systems without modifying the NetHack symbols file. It is used like this:
export NETHACKOPTIONS=symset:IBMgraphics
nethack | tolocal
It works with IBMgraphics, IBMGraphics_1, IBMGraphics_2, RogueIBM, RogueEpyx and RogueWindows
This also works with many other code pages and other programs.
Activity
ostrosablin commentedon Apr 24, 2026
Actually, there's already several documented ways to do just-in-time remap of IBM charset into UTF8 presentation for use with any modern UTF8 terminal seamlessly: konwert and filterm.
https://nethackwiki.com/wiki/Konwert
https://nethackwiki.com/wiki/IBMgraphics#Using_konwert.2C_filterm.2C_or_cp437_.28any_terminal.29
Huge advantage of these is that they are present in repos of majority Linux distros and work flawlessly with both locally running NetHack instance, and public servers over ssh/telnet. It's as simple as this and works with any NetHack version with IBMgraphics support:
filterm ascii-ascii cp437-utf8 nethack
abcbarryn commentedon Apr 24, 2026
Ok, nice to know. This tool: tolocal, has been around now for a few years and it has some features...
Simpler command line, it reads your current terminals code so if it's not UTF8 you don't need to tell it. It also defaults to CP437 so you don't need to tell it that either. This also works flawlessly with both ssh and telnet
ssh -t user@host 'export NETHACKOPTIONS=symset:IBMgraphics ; nethack' | tolocal