Feat: Add custom error message.

src/main.rs

@@ -1,6 +1,4 @@
 use clap::Parser;
-use std::fs::File;
-use std::io::{BufRead, BufReader};
 
 // Search for a pattern in a file and display the lines that contain it.
 #[derive(Parser)]
@@ -9,18 +7,21 @@ struct Cli {
     path: std::path::PathBuf,
 }
 
-fn main() -> std::io::Result<()> {
+#[derive(Debug)]
+struct CustomError(String);
+
+fn main() -> Result<(), CustomError> {
     let args = Cli::parse();
 
-    let f = File::open(&args.path)?;
+    // let content = std::fs::read_to_string(&args.path).expect("Could not read file.");
-    let mut reader = BufReader::new(f);
-    let mut line = String::new();
 
-    while reader.read_line(&mut line)? > 0 {
+    let content = std::fs::read_to_string(&args.path)
+        .map_err(|err| CustomError(format!("Error reading `{}`: {}", args.path.display(), err)))?;
+
+    for line in content.lines() {
         if line.contains(&args.pattern) {
             println!("{}", line)
         }
-        line.clear();
     }
 
     Ok(())