chore: add install and usage instructions to README

.markdownlint.yaml

@@ -0,0 +1,2 @@
+MD013:
+  code_blocks: false

README.md

@@ -15,6 +15,53 @@ This project provides three crates:
 * [rsjsonnet-front](rsjsonnet-front/README.md): a library built on top of
   rsjsonnet-lang and provides easy source loading and error printing.
 
+## Command line program
+
+### Pre-built binaries
+
+You can download binaries of the command line for Linux and Windows from the
+[GitHub releases page](https://github.com/eduardosm/rsjsonnet/releases).
+
+### Build from source
+
+If you have a Rust toolchain installed on your system, you can build the
+latest version with:
+
+```sh
+cargo install --locked rsjsonnet
+```
+
+### Usage
+
+rsjsonnet provides a command line interface similar to the one of the official
+implementation.
+
+```text
+Usage: rsjsonnet [OPTIONS] <filename>
+
+Arguments:
+  <filename>
+
+Options:
+  -e, --exec                      Treat filename as code
+  -J, --jpath <dir>               Specify an additional library search dir (right-most wins)
+  -o, --output-file <file>        Write to the output file rather than stdout
+  -m, --multi <dir>               Write multiple files to the directory, list files on stdout
+  -y, --yaml-stream               Write output as a YAML stream of JSON documents
+  -S, --string                    Expect a string, manifest as plain text
+  -s, --max-stack <n>             Number of allowed stack frames
+  -t, --max-trace <n>             Max length of stack trace before cropping
+  -V, --ext-str <var=[val]>
+      --ext-str-file <var=file>
+      --ext-code <var[=code]>
+      --ext-code-file <var=file>
+  -A, --tla-str <var[=val]>
+      --tla-str-file <var=file>
+      --tla-code <var[=code]>
+      --tla-code-file <var=file>
+  -h, --help                      Print help
+```
+
 ## License
 
 Licensed under either of