Macro cmd_execute 

cmd_execute!() { /* proc-macro */ }

This macro will yield an expression of type &'static [u8; N] which is the output of the command.

let hash = cmd_execute!("git rev-parse --short HEAD"); // git rev-parse --short HEAD | tr -d '\n\r'
let date = cmd_execute!("git log -1 --format=%cd");
let latest_tag = cmd_execute!("git describe --tags --abbrev=0");
let sub_version = cmd_execute!("git rev-list `git describe --tags --abbrev=0`..HEAD --count --first-parent");

println!("{}", String::from_utf8_lossy(hash).trim_end());

let cargo = cmd_execute!("cat Cargo.toml");
let bytes = include_bytes!("../Cargo.toml");
assert_eq!(cargo, bytes);