Add --outfile option to solana-keygen

src/bin/genesis.rs

@@ -23,7 +23,6 @@ fn main() -> Result<(), Box<error::Error>> {
                 .value_name("NUMBER")
                 .takes_value(true)
                 .required(true)
-                .default_value("0")
                 .help("Number of tokens with which to initialize mint"),
         )
         .get_matches();

src/bin/keygen.rs

@@ -1,14 +1,43 @@
+extern crate clap;
 extern crate ring;
 extern crate serde_json;
 
+use clap::{App, Arg};
 use ring::rand::SystemRandom;
 use ring::signature::Ed25519KeyPair;
 use std::error;
+use std::fs::{self, File};
+use std::io::Write;
+use std::path::Path;
 
 fn main() -> Result<(), Box<error::Error>> {
+    let matches = App::new("solana-genesis")
+        .arg(
+            Arg::with_name("outfile")
+                .short("o")
+                .long("outfile")
+                .value_name("PATH")
+                .takes_value(true)
+                .default_value("~/.config/solana/id.json")
+                .help("Number of tokens with which to initialize mint"),
+        )
+        .get_matches();
+
     let rnd = SystemRandom::new();
     let pkcs8_bytes = Ed25519KeyPair::generate_pkcs8(&rnd)?;
     let serialized = serde_json::to_string(&pkcs8_bytes.to_vec())?;
-    println!("{}", serialized);
+
+    let outfile = matches.value_of("outfile").unwrap();
+
+    if outfile == "-" {
+        println!("{}", serialized);
+    } else {
+        if let Some(outdir) = Path::new(outfile).parent() {
+            fs::create_dir_all(outdir)?;
+        }
+        let mut f = File::create(outfile)?;
+        f.write_all(&serialized.into_bytes())?;
+    }
+
     Ok(())
 }