CLI reference

Meta: enumerated from cmd/dang/ (root main.go, repl_commands.go). The binary is a single Cobra command (dang) with one subcommand (fmt); running scripts, directory modules, the REPL, and LSP are all modes of the root command — there is no run/check subcommand.

Synopsis

dang [flags] [file|directory]
dang <file.dang>     # run a single script
dang <directory>     # run a directory as a module
dang                 # no path -> interactive REPL
dang fmt [flags] [path...]

Root command

dang <file.dang> — run a single .dang script (RunFile)
dang <directory> — run all .dang files in the directory as one module (RunDir). See Modules and imports.
dang (no args) — start the interactive REPL (TUI)
accepts at most one positional path argument

Root flags

-d, --debug — enable debug logging (slog at debug level)
--debug-addr <addr> — serve debug/pprof handlers on this address (e.g. localhost:6060)
--clear-cache — clear the GraphQL schema cache and exit. Cache lives under $XDG_CACHE_HOME/dang/schemas (or ~/.cache/dang/schemas).
--lsp — run as a Language Server (JSON-RPC over stdio)
--lsp-log-file <path> — LSP log file (defaults to stderr)
--cpuprofile <file> — write a CPU profile to file
--version — print version (v0.1.0, commit dev) — provided by the fang wrapper
-h, --help

`dang fmt`

format Dang source according to the canonical style. See Syntax.
args: one or more files/directories (directories are scanned for *.dang, non-recursively)
flags:
- -w, --write — write the result back to the source file (default: print to stdout)
- -l, --list — list files that would be formatted (or, with -w, that were changed)

REPL

Started by running dang with no path. Banner:

Welcome to Dang REPL v0.1.0
Imports: GitHub, Dagger

Type :help for commands, Tab for completion, Alt+Enter for multiline, Ctrl+D to exit

The Imports: line appears only when dang.toml configures imports.

REPL commands (prefix :):

:help — list commands
:exit / :quit — leave the REPL (also Ctrl+D)
:doc — interactive API/schema browser. See GraphQL interop.
:env — show environment bindings
:type <expr> — show the inferred type of an expression
:find / :search <pattern> — find functions/types by pattern
:reset — rebuild the environment from imports
:clear — clear the screen
:debug — toggle debug mode
:version — show version + configured imports
:history — show recent input history

Input keys: Tab completion, Up/Down history, Alt+Enter (or Shift+Enter under a Kitty-protocol terminal) for multiline, Ctrl+L to clear.

Configuration

GraphQL connections are configured per-import in dang.toml under [imports.<Name>]. Keys: dagger, schema (local .graphqls SDL path), endpoint, service (command that prints its endpoint/session JSON), authorization, headers.
endpoint, authorization, and headers values support ${VAR} environment expansion. $(...) command substitution is not supported (use an env var instead). See Getting started and GraphQL interop.
config is discovered by walking up from the working directory, stopping at a .git boundary.

Exit codes

0 — success
1 — any error (runtime error, assertion failure, type/parse error, or a CLI usage error); there is no distinct exit code per failure kind

Editor integration

LSP via dang --lsp (handler in pkg/lsp) — point your editor's LSP client at the dang binary with that flag
editor configs under editors/ (nvim, vscode, zed)