diff --git a/examples/cat.rs b/examples/cat.rs
index dba0411..375996f 100644
--- a/examples/cat.rs
+++ b/examples/cat.rs
@@ -13,7 +13,7 @@ fn main() -> io::Result<()> {
     let buf_rdr = BufStream::new(file);
     let fs = FileSystem::new(buf_rdr, FsOptions::new())?;
     let root_dir = fs.root_dir();
-    let mut file = root_dir.open_file(&env::args().nth(1).unwrap())?;
+    let mut file = root_dir.open_file(&env::args().nth(1).expect("filename expected"))?;
     let mut buf = vec![];
     file.read_to_end(&mut buf)?;
     print!("{}", String::from_utf8_lossy(&buf));
diff --git a/examples/mkfatfs.rs b/examples/mkfatfs.rs
new file mode 100644
index 0000000..cd0d40a
--- /dev/null
+++ b/examples/mkfatfs.rs
@@ -0,0 +1,16 @@
+extern crate fatfs;
+extern crate fscommon;
+
+use std::env;
+use std::fs;
+use std::io;
+
+use fscommon::BufStream;
+
+fn main() -> io::Result<()> {
+    let filename = env::args().nth(1).expect("image path expected");
+    let file = fs::OpenOptions::new().read(true).write(true).open(&filename)?;
+    let buf_file = BufStream::new(file);
+    fatfs::format_volume(buf_file, fatfs::FormatVolumeOptions::new())?;
+    Ok(())
+}