aquatic-prime.rs: Add a "usage" message

1 files changed, 8 insertions, 0 deletions

diff --git a/license-generator/src/bin/aquatic-prime.rs b/license-generator/src/bin/aquatic-prime.rs
index 5864a01..ec592b1 100644
--- a/license-generator/src/bin/aquatic-prime.rs
+++ b/license-generator/src/bin/aquatic-prime.rs
@@ -5,9 +5,12 @@ extern crate serde;
 extern crate serde_derive;
 
 use std::env;
+use std::process;
 
 use aquatic_prime::AquaticPrime;
 
+const EX_USAGE: i32 = 64;
+
 #[derive(Serialize)]
 struct LicenseData<'a> {
     #[serde(rename = "Name")]
@@ -20,6 +23,11 @@ struct LicenseData<'a> {
 fn main() {
     let args: Vec<String> = env::args().collect();
 
+    if args.len() != 5 {
+        println!("Usage: aquatic-prime PUBLIC_KEY PRIVATE_KEY NAME EMAIL");
+        process::exit(EX_USAGE);
+    }
+
     let aquatic_prime = AquaticPrime::new(&args[1], &args[2]);
 
     let license_data = LicenseData {