diff --git a/env/env.rs b/env/env.rs
index fad68a21c..f74f80db2 100644
--- a/env/env.rs
+++ b/env/env.rs
@@ -92,13 +92,13 @@ fn main() {
                 }
             }
         } else if opt.starts_with("--") {
-            match *opt {
-                ~"--help" => { usage(prog); return }
-                ~"--version" => { version(); return }
+            match opt.as_slice() {
+                "--help" => { usage(prog); return }
+                "--version" => { version(); return }
 
-                ~"--ignore-environment" => opts.ignore_env = true,
-                ~"--null" => opts.null = true,
-                ~"--unset" => {
+                "--ignore-environment" => opts.ignore_env = true,
+                "--null" => opts.null = true,
+                "--unset" => {
                     let var = iter.next();
 
                     match var {
diff --git a/head/head.rs b/head/head.rs
index 4f1cf4848..8ed5212b5 100644
--- a/head/head.rs
+++ b/head/head.rs
@@ -128,7 +128,7 @@ fn obsolete (options: &mut ~[~str]) -> Option<uint> {
 }
 
 fn head<T: Reader> (reader: &mut BufferedReader<T>, line_count:uint) {
-    for line in reader.lines().take(line_count) { print!("{:s}", line); }
+    for line in reader.lines().take(line_count) { print!("{}", line); }
 }
 
 fn version () {
diff --git a/rm/rm.rs b/rm/rm.rs
index 9cec82474..ec9b987ab 100644
--- a/rm/rm.rs
+++ b/rm/rm.rs
@@ -87,10 +87,10 @@ fn main() {
             } else if matches.opt_present("I") {
                 InteractiveOnce
             } else if matches.opt_present("interactive") {
-                match matches.opt_str("interactive").unwrap() {
-                    ~"none" => InteractiveNone,
-                    ~"once" => InteractiveOnce,
-                    ~"always" => InteractiveAlways,
+                match matches.opt_str("interactive").unwrap().as_slice() {
+                    "none" => InteractiveNone,
+                    "once" => InteractiveOnce,
+                    "always" => InteractiveAlways,
                     val => {
                         crash!(1, "Invalid argument to interactive ({})", val)
                     }
diff --git a/sleep/sleep.rs b/sleep/sleep.rs
index bd7138449..98b2c75be 100644
--- a/sleep/sleep.rs
+++ b/sleep/sleep.rs
@@ -88,7 +88,7 @@ fn sleep(args: &[~str]) {
 }
 
 fn match_suffix(arg: &mut ~str) -> Result<int, ~str> {
-    let result = match (*arg).pop_char() {
+    let result = match (*arg).pop_char().unwrap() {
         's' | 'S' => Ok(1),
         'm' | 'M' => Ok(60),
         'h' | 'H' => Ok(60 * 60),