Move solana-keygen into keygen/

sdk/Cargo.toml

@@ -10,7 +10,9 @@ license = "Apache-2.0"
 bincode = "1.0.0"
 byteorder = "1.2.1"
 bs58 = "0.2.0"
+dirs = "1.0.2"
 chrono = { version = "0.4.0", features = ["serde"] }
+clap = "2.31"
 generic-array = { version = "0.12.0", default-features = false, features = ["serde"] }
 log = "0.4.2"
 ring = "0.13.2"
@@ -20,3 +22,8 @@ serde_derive = "1.0.82"
 serde_json = "1.0.10"
 untrusted = "0.6.2"
 
+[[bin]]
+name = "solana-keygen"
+path = "src/bin/keygen.rs"
+
+

sdk/src/bin/keygen.rs

@@ -0,0 +1,36 @@
+#[macro_use]
+extern crate clap;
+extern crate dirs;
+extern crate solana_sdk;
+
+use clap::{App, Arg};
+use solana_sdk::signature::gen_keypair_file;
+use std::error;
+
+fn main() -> Result<(), Box<dyn error::Error>> {
+    let matches = App::new("solana-keygen")
+        .version(crate_version!())
+        .arg(
+            Arg::with_name("outfile")
+                .short("o")
+                .long("outfile")
+                .value_name("PATH")
+                .takes_value(true)
+                .help("Path to generated file"),
+        )
+        .get_matches();
+
+    let mut path = dirs::home_dir().expect("home directory");
+    let outfile = if matches.is_present("outfile") {
+        matches.value_of("outfile").unwrap()
+    } else {
+        path.extend(&[".config", "solana", "id.json"]);
+        path.to_str().unwrap()
+    };
+
+    let serialized_keypair = gen_keypair_file(outfile.to_string())?;
+    if outfile == "-" {
+        println!("{}", serialized_keypair);
+    }
+    Ok(())
+}