cli arguments should feel like scp

src/main.rs

@@ -3,6 +3,8 @@ mod utils;
 
 use clap::{App, Arg};
 use utils::split_and_copy_binary_file;
+use std::env;
+use std::process;
 
 fn main() {
     let matches = App::new("Zap — Fast single file copy")
@@ -14,30 +16,17 @@ fn main() {
             .help("The input file path")
             .required(true)
             .index(1))
+        .arg(Arg::new("user_host_path")
+            .help("Specifies user@host:remote_path")
+            .required(true)
+            .value_name("user@host:remote_path")
+            .index(2))
         .arg(Arg::new("streams")
             .short('c')
             .long("streams")
             .help("The number of parallel streams")
             .default_value("20")
             .takes_value(true))
-        .arg(Arg::new("user")
-            .short('u')
-            .long("user")
-            .help("The username for the remote server")
-            .takes_value(true)
-            .required(true))
-        .arg(Arg::new("server")
-            .short('s')
-            .long("server")
-            .help("The hostname of the remote server")
-            .takes_value(true)
-            .required(true))
-        .arg(Arg::new("remote_path")
-            .short('p')
-            .long("remote-path")
-            .help("The remote path where streams will be stored")
-            .takes_value(true)
-            .required(true))
         .arg(Arg::new("ssh_key_path")
             .short('i')
             .long("ssh-key-path")
@@ -52,11 +41,36 @@ fn main() {
         .get_matches();
 
     let input_file_path = matches.value_of("input_file").unwrap();
+
+    let user_host_path = matches.value_of("user_host_path").unwrap();
+    let parts: Vec<&str> = user_host_path.splitn(2, ':').collect();
+    let user_host = parts[0];
+
+    // Use remote ssh CWD "." if no path provided after user@host:
+    let remote_path = if let Some(path) = parts.get(1) {
+        if path.is_empty() { "." } else { path }
+    } else {
+        "."
+    };
+
+    let host_parts: Vec<&str> = user_host.split('@').collect();
+    let (remote_user, remote_host) = match host_parts.as_slice() {
+        [user, host] => (user.to_string(), host.to_string()),
+        [host] => {
+            let user_env = env::var("USER").unwrap_or_else(|_| {
+                eprintln!("$USER environment variable is not set");
+                process::exit(1);
+            });
+            (user_env, host.to_string())
+        },
+        _ => {
+            eprintln!("Invalid format for user@hostname");
+            process::exit(1);
+        }
+    };
+
     let num_streams: usize = matches.value_of("streams").unwrap().parse()
         .expect("num_streams must be an integer");
-    let remote_user = matches.value_of("user").unwrap();
-    let remote_host = matches.value_of("server").unwrap();
-    let remote_path = matches.value_of("remote_path").unwrap();
     let ssh_key_path = matches.value_of("ssh_key_path");
     let retries: u32 = matches.value_of("retries").unwrap().parse()
         .expect("retries must be an integer");
@@ -65,11 +79,12 @@ fn main() {
     split_and_copy_binary_file(
         input_file_path, 
         num_streams, 
-        remote_user, 
-        remote_host, 
-        remote_path, 
+        &remote_user, 
+        &remote_host, 
+        remote_path,
         ssh_key_path.as_deref(),
         max_threads,
         retries
     );
 }
+

src/ssh_comm.rs

@@ -17,13 +17,12 @@ pub fn stream_stream_to_remote(
     remote_host: &str,
     remote_path: &str,
     ssh_key_path: Option<&str>,
-    retries: u32, // Added retries as a parameter
+    retries: u32,
 ) -> Result<(), String> {
     let mut attempt = 0;
     while attempt <= retries {
         let user_host = format!("{}@{}", remote_user, remote_host);
         let stream_command = format!("cat > {}/stream_{}.bin", remote_path, stream_num);
-
         let mut ssh_args = vec![
             "-o", "StrictHostKeyChecking=no",
             &user_host,