src/buffer.rs

@@ -2,6 +2,7 @@ use std::io as stdio;
 use stdio::stdin;
 use crate::parser;
 use crate::job;
+use crate::error::command_not_found;
 
 pub struct Buffer {
     buffer: String,
@@ -34,6 +35,7 @@ impl Buffer {
     pub fn try_spawn(&mut self) -> Option<i32> {
         if ! self.buffer.is_empty() {
             self.argv = parser::parse(&self.buffer);
+            let command_name = self.argv[0].to_string();
             let result = job::execute(&mut self.argv);
 
             if result.is_ok() {
@@ -43,8 +45,7 @@ impl Buffer {
                     return Some(result.code().unwrap());
                 }
             } else {
-                eprintln!("{}", result.unwrap_err());
-                return Some(127);
+                return Some(command_not_found(&command_name));
             }
         }
 

src/error.rs

@@ -0,0 +1,11 @@
+use std::env;
+
+fn error(message: &str) {
+    eprintln!("{}: {}", env::args().next().unwrap(), message);
+}
+
+pub fn command_not_found(command: &String) -> i32 {
+    let message = command.to_owned() + ": command not found";
+    error(&message);
+    127
+}

src/main.rs

@@ -2,6 +2,7 @@ mod buffer;
 mod parser;
 mod job;
 mod variables;
+mod error;
 
 use std::process::exit;
 use variables::Variables;