Command-line tools

Use ku --version to identify the executable and ku --help to inspect available options.

Command	Purpose
ku check main.ku	Check without executing
ku check --json main.ku	Emit JSON Lines diagnostics for tools
ku run main.ku	Interpret a program
ku build main.ku	Build the default runner
ku build --backend c main.ku -o app	Compile and link a native C executable
ku build --native main.ku	Emit C only, without linking
ku ir main.ku	Print optimized IR
ku llvm main.ku	Emit experimental LLVM text, without an executable
ku create Hello --template basic	Create a project
ku init --template basic	Initialize the current directory
ku template list	List templates
ku package resolve --locked	Resolve using the project lock
ku package gc	Remove unused package cache entries

Choose an execution path

check and run do not require Rust or C compilers. Default build needs Rust 1.89.0, a linker and the archive’s full libku.rlib / deps layout. Its runner embeds only the entry file; local imports still need their original sources. Native C needs a C compiler, expands the import graph and produces a program independent of Ku source files.

Use app.exe on Windows. See installation and backend support. There is no ku fmt, ku test or ku doc command; VS Code formatting is an extension feature.

Controlled execution

ku supervise explicitly manages whole-program workers. It is not automatically applied to run or individual HTTP requests. Linux requires delegated cgroup v2; Windows limits committed memory. This isolation mode is not supported natively on macOS. See platform and process limits for setup and failure behavior.