explict version informations

rustfmt-bin/build.rs

@@ -27,11 +27,19 @@ fn main() {
 // (git not installed or if this is not a git repository) just return an empty string.
 fn commit_info() -> String {
     match (commit_hash(), commit_date()) {
-        (Some(hash), Some(date)) => format!(" ({} {})", hash.trim_right(), date),
+        (Some(hash), Some(date)) => format!("{} ({} {})", channel(), hash.trim_right(), date),
         _ => String::new(),
     }
 }
 
+fn channel() -> String {
+    if let Ok(channel) = env::var("CFG_RELEASE_CHANNEL") {
+        channel
+    } else {
+        "nightly".to_owned()
+    }
+}
+
 fn commit_hash() -> Option<String> {
     Command::new("git")
         .args(&["rev-parse", "--short", "HEAD"])

rustfmt-bin/src/main.rs

@@ -387,10 +387,13 @@ fn print_usage_to_stdout(opts: &Options, reason: &str) {
 
 fn print_version() {
     println!(
-        "{}-nightly{}",
-        option_env!("CARGO_PKG_VERSION").unwrap_or("unknown"),
-        include_str!(concat!(env!("OUT_DIR"), "/commit-info.txt"))
-    )
+        "rustfmt {}",
+        concat!(
+            env!("CARGO_PKG_VERSION"),
+            "-",
+            include_str!(concat!(env!("OUT_DIR"), "/commit-info.txt"))
+        )
+    );
 }
 
 fn determine_operation(matches: &Matches) -> FmtResult<Operation> {