Jitzu Shell

The Jitzu shell is a feature-rich interactive environment that blends a Unix-style command line with the full Jitzu language. You can run shell commands, write Jitzu expressions, and pipe between them — all in one place.

Launching the Shell

Start the shell by running jz with no arguments:

jz v0.2.0

• runtime    : 10.0.0
• config     : ~/.jitzu/config.jz
• platform   : Unix

Type `help` to get started.

simon@dev ~/projects/api (main) *              14:23
>

The prompt shows your username, hostname, current directory (relative to the git root if inside a repo), git branch with status indicators (* dirty, + staged, ? untracked), and the current time.

Use --no-splash to skip the welcome banner.

Mixing Code and Commands

The shell automatically detects whether your input is Jitzu code or a shell command. Jitzu code is tried first; if parsing fails, the input is executed as an OS command.

Jitzu Expressions

> 1 + 1
2

> let greeting = "hello from the shell"
> greeting.ToUpper()
"HELLO FROM THE SHELL"

> fun factorial(n: Int): Int {
|     if n <= 1 { 1 } else { n * factorial(n - 1) }
| }
> factorial(10)
3628800

OS Commands

Commands that aren’t valid Jitzu code fall through to the system shell. Many common commands like ls, grep, and find are implemented as builtins with colored output, but any program on your PATH works too:

> git log --oneline -3
a1b2c3d Add pattern matching support
b2c3d4e Fix lexer edge case
c3d4e5f Initial commit

> dotnet build
Build succeeded.

Command Substitution

Use $(command) to capture the output of a command and insert it inline. Nesting is supported.

> echo "I am in $(pwd)"
I am in /home/simon/projects/api

> echo "Branch: $(git branch --show-current)"
Branch: main

Environment Variables

Shell-style variable expansion works with $VAR and \${VAR} syntax. Use export to set and unset to remove environment variables.

> export EDITOR=nvim
> echo $EDITOR
nvim

> echo ${HOME}
/home/simon

Single-quoted strings suppress expansion: echo '$HOME' prints the literal text $HOME.

Multi-line Input

When a line ends with an unclosed brace, the shell continues reading on the next line with a | continuation prompt:

> let person = {
|   name = "Alice",
|   age = 30,
|   address = {
|     city = "New York",
|     zip = "10001"
|   }
| }
> person.address.city
"New York"

Glob Expansion

Arguments containing * or ? are expanded to matching file paths. Recursive ** patterns are also supported.

> ls *.cs
Program.cs  Lexer.cs  Parser.cs

> find src/**/*.cs
src/Core/Compiler.cs
src/Core/Interpreter.cs
src/Runtime/Stack.cs

Sourcing Scripts

The source command (or its shorthand .) executes a .jz file line-by-line in the current session, so any variables or functions it defines remain available:

> source ~/scripts/helpers.jz
> my_helper_function("test")
"processed: test"

Introspection

The shell includes commands to inspect the current session state:

• vars — list all defined variables and their types
• types — show available types (built-in, user-defined, imported)
• functions — show defined functions
• reset — clear all session state and start fresh

Error Handling

Errors are displayed gracefully without crashing the shell. The prompt arrow turns red after a failed command:

> 10 / 0
Error: Division by zero

> cd nonexistent
No such directory: nonexistent
Did you mean src/?