docs: add ls example (#72)

Author: robjtede

examples/ls.rs

@@ -0,0 +1,27 @@
+//! Emulates running `ls -la` in the terminal, showing human-readable file sizes and file names.
+
+use std::{fs, io};
+
+fn main() -> io::Result<()> {
+    let dir = fs::read_dir(".")?;
+
+    for entry in dir {
+        let entry = entry?;
+
+        let md = entry.metadata()?;
+
+        let file_name = entry.file_name();
+        let file_name = file_name.to_string_lossy();
+
+        if md.is_file() {
+            let file_size = md.len();
+            let file_size = bytesize::ByteSize::b(file_size);
+
+            println!("{file_size}\t{file_name}");
+        } else {
+            println!("-\t{file_name}");
+        }
+    }
+
+    Ok(())
+}