luac command — Glaurung

use it for

The parser recognizes Lua 5.1 through 5.4 and LuaJIT bytecode. It reports metadata and available source-name information.

Run glaurung luac --help on your installed version before putting the command in a script. Glaurung is still pre-1.0.

input: A Lua 5.1–5.4 or LuaJIT bytecode chunk.
output: Bytecode family, format byte, endianness, and any stored source name.
mode: read only. The examples leave the input unchanged.

command shape

short form

$ glaurung luac PATH [--json]

The installed parser is authoritative: glaurung luac --help

run it

The source path is metadata embedded by the compiler; it need not exist on your machine.

run

from the engine checkout

$ glaurung luac samples/binaries/platforms/linux/amd64/lua/hello-lua5.4.luac --json

output

captured result captured 2026-08-31

{"kind":"Lua 5.3","format":0,"source":"@/workspace/source/lua/hello.lua","little_endian":true}

captured 2026-08-31.

Read the result: luac recognizes the header. It does not decompile the chunk into Lua source.

Use a known native binary as a negative control for format detection.

run

from the engine checkout

$ glaurung luac /bin/ls

output

captured result captured on Ubuntu, 2026-08-31

Error: not Lua bytecode: /bin/ls

captured on Ubuntu, 2026-08-31.

Read the result: The command stops at the header check. It does not try to interpret arbitrary native bytes as Lua instructions.

used above

These are the flags used by the examples. Run glaurung luac --help for the complete parser help.

keep working