/// Collect candidate hashes based on options and match them against a calculated hash
 mod verify;
 
+/// Problem running the program
+const EXIT_ERR: i32 = 1;
+/// Verification was performed and was not a match
+const EXIT_MISMATCH: i32 = 2;
+
 #[derive(StructOpt)]
 #[structopt(name = "hashgood")]
 pub struct Opt {
-    /// Read the hash from the clipboard
-    #[cfg(feature = "paste")]
-    #[structopt(short = "p", long = "paste")]
-    paste: bool,
-
     /// Disable ANSI colours in output
     #[structopt(short = "C", long = "no-colour")]
     no_colour: bool,
     hash: Option<String>,
 }
 
-impl Opt {
-    fn get_paste(&self) -> bool {
-        #[cfg(feature = "paste")]
-        {
-            self.paste
-        }
-        #[cfg(not(feature = "paste"))]
-        {
-            false
-        }
-    }
-}
-
 /// Types of supported digest algorithm
 #[derive(Debug, PartialEq, Copy, Clone)]
 pub enum Algorithm {
     Md5,
     Sha1,
     Sha256,
+    Sha512,
 }
 
 impl Algorithm {
             16 => Ok(Algorithm::Md5),
             20 => Ok(Algorithm::Sha1),
             32 => Ok(Algorithm::Sha256),
+            64 => Ok(Algorithm::Sha512),
             _ => Err(format!("Unrecognised hash length: {} bytes", len)),
         }
     }
 #[derive(Debug, PartialEq)]
 pub enum VerificationSource {
     CommandArgument,
-    Clipboard,
     RawFile(String),
     DigestsFile(String),
 }
 }
 
 /// Summary of an atetmpt to match the calculated digest against candidates
+#[derive(PartialEq)]
 pub enum MatchLevel {
     Ok,
     Maybe,
 fn main() {
     hashgood().unwrap_or_else(|e| {
         eprintln!("Error: {}", e);
-        process::exit(1);
+        process::exit(EXIT_ERR);
     });
 }
 
             if c.alg == alg {
                 let hash = Hash::new(alg, bytes, &opt.input);
                 let verification = verify::verify_hash(&hash, &c);
+                let successful_match = verification.match_level == MatchLevel::Ok;
                 display::print_hash(
                     &hash,
                     verification.comparison_hash,
                 )?;
                 display::print_messages(verification.messages, opt.no_colour)?;
                 display::print_match_level(verification.match_level, opt.no_colour)?;
+                if !successful_match {
+                    process::exit(EXIT_MISMATCH);
+                }
             }
         }
     } else {
         // If no candidate, calculate all three common digest types for output
         let hashes = calculate::create_digests(
-            &[Algorithm::Md5, Algorithm::Sha1, Algorithm::Sha256],
+            &[
+                Algorithm::Md5,
+                Algorithm::Sha1,
+                Algorithm::Sha256,
+                Algorithm::Sha512,
+            ],
             input,
         )?;
         for (alg, bytes) in hashes {
 /// Parse the command line options and check for ambiguous or inconsistent settings
 fn get_verified_options() -> Result<Opt, String> {
     let opt = Opt::from_args();
-    let hash_methods =
-        opt.hash.is_some() as i32 + opt.get_paste() as i32 + opt.hash_file.is_some() as i32;
+    let hash_methods = opt.hash.is_some() as i32 + opt.hash_file.is_some() as i32;
     if hash_methods > 1 {
         if opt.hash.is_some() {
             eprintln!("* specified as command line argument");
         }
-        if opt.get_paste() {
-            eprintln!("* paste from clipboard (-p)")
-        }
         if opt.hash_file.is_some() {
             eprintln!("* check hash from file (-c)")
         }