RTL-SDR is both an executable binary that can be run, and a library that can be used in Rust programs.
Installing the rtlsdr_demo executable
Assuming you have Rust/Cargo installed, run this command in a terminal:
cargo install rtlsdr
It will make the rtlsdr_demo command available in your PATH if you've allowed the PATH to be modified when installing Rust. cargo uninstall rtlsdr uninstalls.
Adding rtlsdr library as a dependency
Run this command in a terminal, in your project's directory:
cargo add rtlsdr
To add it manually, edit your project's Cargo.toml file and add to the [dependencies] section:
rtlsdr = "0.1.4"
The rtlsdr library will be automatically available globally.
Read the rtlsdr library documentation.