xgo/docs/tengo-cli.md

# Tengo CLI Tool

Tengo is designed as an embedding script language for Go, but, it can also be
compiled and executed as native binary using `tengo` CLI tool.

## Installing Tengo CLI

To install `tengo` tool, run:

```bash
go get github.com/d5/tengo/cmd/tengo
```

Or, you can download the precompiled binaries from
[here](https://github.com/d5/tengo/releases/latest).

## Compiling and Executing Tengo Code

You can directly execute the Tengo source code by running `tengo` tool with
your Tengo source file (`*.tengo`).

```bash
tengo myapp.tengo
```

Or, you can compile the code into a binary file and execute it later.

```bash
tengo -o myapp myapp.tengo   # compile 'myapp.tengo' into binary file 'myapp'
tengo myapp                  # execute the compiled binary `myapp`
```

Or, you can make tengo source file executable

```bash
# copy tengo executable to a dir where PATH environment variable includes
cp tengo /usr/local/bin/

# add shebang line to source file
cat > myapp.tengo << EOF
#!/usr/local/bin/tengo
fmt := import("fmt")
fmt.println("Hello World!")
EOF

# make myapp.tengo file executable
chmod +x myapp.tengo

# run your script
./myapp.tengo
```

**Note: Your source file must have `.tengo` extension.**

## Resolving Relative Import Paths

If there are tengo source module files which are imported with relative import
paths, CLI has `-resolve` flag. Flag enables to import a module relative to
importing file. This behavior will be default at version 3.

## Tengo REPL

You can run Tengo [REPL](https://en.wikipedia.org/wiki/Read–eval–print_loop)
if you run `tengo` with no arguments.

```bash
tengo
```