diff --git a/src/uu/basename/src/basename.rs b/src/uu/basename/src/basename.rs
index 84521bdd1..7b02a7a83 100644
--- a/src/uu/basename/src/basename.rs
+++ b/src/uu/basename/src/basename.rs
@@ -111,6 +111,7 @@ fn basename(fullname: &str, suffix: &str) -> String {
     }
 }
 
+#[allow(clippy::manual_strip)] // can be replaced with strip_suffix once the minimum rust version is 1.45
 fn strip_suffix(name: &str, suffix: &str) -> String {
     if name == suffix {
         return name.to_owned();
diff --git a/src/uu/chgrp/src/chgrp.rs b/src/uu/chgrp/src/chgrp.rs
index b4c3360c5..592a0a905 100644
--- a/src/uu/chgrp/src/chgrp.rs
+++ b/src/uu/chgrp/src/chgrp.rs
@@ -286,7 +286,7 @@ impl Chgrper {
 
             ret = match wrap_chgrp(path, &meta, self.dest_gid, follow, self.verbosity.clone()) {
                 Ok(n) => {
-                    if n != "" {
+                    if !n.is_empty() {
                         show_info!("{}", n);
                     }
                     0
diff --git a/src/uu/chmod/src/chmod.rs b/src/uu/chmod/src/chmod.rs
index d9d8c8cf2..dc11be7b8 100644
--- a/src/uu/chmod/src/chmod.rs
+++ b/src/uu/chmod/src/chmod.rs
@@ -171,13 +171,13 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
 // of a prefix '-' if it's associated with MODE
 // e.g. "chmod -v -xw -R FILE" -> "chmod -v xw -R FILE"
 pub fn strip_minus_from_mode(args: &mut Vec<String>) -> bool {
-    for i in 0..args.len() {
-        if args[i].starts_with("-") {
-            if let Some(second) = args[i].chars().nth(1) {
+    for arg in args {
+        if arg.starts_with('-') {
+            if let Some(second) = arg.chars().nth(1) {
                 match second {
                     'r' | 'w' | 'x' | 'X' | 's' | 't' | 'u' | 'g' | 'o' | '0'..='7' => {
                         // TODO: use strip_prefix() once minimum rust version reaches 1.45.0
-                        args[i] = args[i][1..args[i].len()].to_string();
+                        *arg = arg[1..arg.len()].to_string();
                         return true;
                     }
                     _ => {}
diff --git a/src/uu/chown/src/chown.rs b/src/uu/chown/src/chown.rs
index 42010de03..0e3273b3b 100644
--- a/src/uu/chown/src/chown.rs
+++ b/src/uu/chown/src/chown.rs
@@ -391,7 +391,7 @@ impl Chowner {
                 self.verbosity.clone(),
             ) {
                 Ok(n) => {
-                    if n != "" {
+                    if !n.is_empty() {
                         show_info!("{}", n);
                     }
                     0
@@ -446,7 +446,7 @@ impl Chowner {
                 self.verbosity.clone(),
             ) {
                 Ok(n) => {
-                    if n != "" {
+                    if !n.is_empty() {
                         show_info!("{}", n);
                     }
                     0
diff --git a/src/uu/chroot/src/chroot.rs b/src/uu/chroot/src/chroot.rs
index 44c5dfa02..7e672da1e 100644
--- a/src/uu/chroot/src/chroot.rs
+++ b/src/uu/chroot/src/chroot.rs
@@ -104,7 +104,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         _ => {
             let mut vector: Vec<&str> = Vec::new();
             for (&k, v) in matches.args.iter() {
-                vector.push(k.clone());
+                vector.push(k);
                 vector.push(&v.vals[0].to_str().unwrap());
             }
             vector
@@ -133,7 +133,7 @@ fn set_context(root: &Path, options: &clap::ArgMatches) {
     let userspec = match userspec_str {
         Some(ref u) => {
             let s: Vec<&str> = u.split(':').collect();
-            if s.len() != 2 || s.iter().any(|&spec| spec == "") {
+            if s.len() != 2 || s.iter().any(|&spec| spec.is_empty()) {
                 crash!(1, "invalid userspec: `{}`", u)
             };
             s
@@ -142,16 +142,16 @@ fn set_context(root: &Path, options: &clap::ArgMatches) {
     };
 
     let (user, group) = if userspec.is_empty() {
-        (&user_str[..], &group_str[..])
+        (user_str, group_str)
     } else {
-        (&userspec[0][..], &userspec[1][..])
+        (userspec[0], userspec[1])
     };
 
     enter_chroot(root);
 
-    set_groups_from_str(&groups_str[..]);
-    set_main_group(&group[..]);
-    set_user(&user[..]);
+    set_groups_from_str(groups_str);
+    set_main_group(group);
+    set_user(user);
 }
 
 fn enter_chroot(root: &Path) {
diff --git a/src/uu/cp/src/cp.rs b/src/uu/cp/src/cp.rs
index 569ee78bc..4e245b298 100644
--- a/src/uu/cp/src/cp.rs
+++ b/src/uu/cp/src/cp.rs
@@ -132,7 +132,9 @@ macro_rules! prompt_yes(
 
 pub type CopyResult<T> = Result<T, Error>;
 pub type Source = PathBuf;
+pub type SourceSlice = Path;
 pub type Target = PathBuf;
+pub type TargetSlice = Path;
 
 /// Specifies whether when overwrite files
 #[derive(Clone, Eq, PartialEq)]
@@ -547,14 +549,13 @@ impl FromStr for Attribute {
 }
 
 fn add_all_attributes() -> Vec<Attribute> {
-    let mut attr = Vec::new();
+    use Attribute::*;
+
+    let mut attr = vec![Ownership, Timestamps, Context, Xattr, Links];
+
     #[cfg(unix)]
-    attr.push(Attribute::Mode);
-    attr.push(Attribute::Ownership);
-    attr.push(Attribute::Timestamps);
-    attr.push(Attribute::Context);
-    attr.push(Attribute::Xattr);
-    attr.push(Attribute::Links);
+    attr.insert(0, Mode);
+
     attr
 }
 
@@ -665,7 +666,7 @@ impl TargetType {
     ///
     /// Treat target as a dir if we have multiple sources or the target
     /// exists and already is a directory
-    fn determine(sources: &[Source], target: &Target) -> TargetType {
+    fn determine(sources: &[Source], target: &TargetSlice) -> TargetType {
         if sources.len() > 1 || target.is_dir() {
             TargetType::Directory
         } else {
@@ -714,7 +715,7 @@ fn parse_path_args(path_args: &[String], options: &Options) -> CopyResult<(Vec<S
 
 fn preserve_hardlinks(
     hard_links: &mut Vec<(String, u64)>,
-    source: &std::path::PathBuf,
+    source: &std::path::Path,
     dest: std::path::PathBuf,
     found_hard_link: &mut bool,
 ) -> CopyResult<()> {
@@ -788,7 +789,7 @@ fn preserve_hardlinks(
 /// Behavior depends on `options`, see [`Options`] for details.
 ///
 /// [`Options`]: ./struct.Options.html
-fn copy(sources: &[Source], target: &Target, options: &Options) -> CopyResult<()> {
+fn copy(sources: &[Source], target: &TargetSlice, options: &Options) -> CopyResult<()> {
     let target_type = TargetType::determine(sources, target);
     verify_target_type(target, &target_type)?;
 
@@ -840,7 +841,7 @@ fn copy(sources: &[Source], target: &Target, options: &Options) -> CopyResult<()
 
 fn construct_dest_path(
     source_path: &Path,
-    target: &Target,
+    target: &TargetSlice,
     target_type: &TargetType,
     options: &Options,
 ) -> CopyResult<PathBuf> {
@@ -870,8 +871,8 @@ fn construct_dest_path(
 }
 
 fn copy_source(
-    source: &Source,
-    target: &Target,
+    source: &SourceSlice,
+    target: &TargetSlice,
     target_type: &TargetType,
     options: &Options,
 ) -> CopyResult<()> {
@@ -912,7 +913,7 @@ fn adjust_canonicalization(p: &Path) -> Cow<Path> {
 ///
 /// Any errors encountered copying files in the tree will be logged but
 /// will not cause a short-circuit.
-fn copy_directory(root: &Path, target: &Target, options: &Options) -> CopyResult<()> {
+fn copy_directory(root: &Path, target: &TargetSlice, options: &Options) -> CopyResult<()> {
     if !options.recursive {
         return Err(format!("omitting directory '{}'", root.display()).into());
     }
@@ -1068,6 +1069,7 @@ fn copy_attribute(source: &Path, dest: &Path, attribute: &Attribute) -> CopyResu
 }
 
 #[cfg(not(windows))]
+#[allow(clippy::unnecessary_wraps)] // needed for windows version
 fn symlink_file(source: &Path, dest: &Path, context: &str) -> CopyResult<()> {
     match std::os::unix::fs::symlink(source, dest).context(context) {
         Ok(_) => Ok(()),
diff --git a/src/uu/cut/src/cut.rs b/src/uu/cut/src/cut.rs
index 6b09b91d9..5bf310daa 100644
--- a/src/uu/cut/src/cut.rs
+++ b/src/uu/cut/src/cut.rs
@@ -406,7 +406,7 @@ fn cut_files(mut filenames: Vec<String>, mode: Mode) -> i32 {
                 continue;
             }
 
-            if !path.metadata().is_ok() {
+            if path.metadata().is_err() {
                 show_error!("{}: No such file or directory", filename);
                 continue;
             }
@@ -487,7 +487,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
                 .help("filter field columns from the input source")
                 .takes_value(true)
                 .allow_hyphen_values(true)
-                .value_name("LIST")                
+                .value_name("LIST")
                 .display_order(4),
         )
         .arg(
@@ -535,40 +535,36 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         matches.value_of(options::CHARACTERS),
         matches.value_of(options::FIELDS),
     ) {
-        (Some(byte_ranges), None, None) => {
-            list_to_ranges(&byte_ranges[..], complement).map(|ranges| {
-                Mode::Bytes(
-                    ranges,
-                    Options {
-                        out_delim: Some(
-                            matches
-                                .value_of(options::OUTPUT_DELIMITER)
-                                .unwrap_or_default()
-                                .to_owned(),
-                        ),
-                        zero_terminated: matches.is_present(options::ZERO_TERMINATED),
-                    },
-                )
-            })
-        }
-        (None, Some(char_ranges), None) => {
-            list_to_ranges(&char_ranges[..], complement).map(|ranges| {
-                Mode::Characters(
-                    ranges,
-                    Options {
-                        out_delim: Some(
-                            matches
-                                .value_of(options::OUTPUT_DELIMITER)
-                                .unwrap_or_default()
-                                .to_owned(),
-                        ),
-                        zero_terminated: matches.is_present(options::ZERO_TERMINATED),
-                    },
-                )
-            })
-        }
+        (Some(byte_ranges), None, None) => list_to_ranges(byte_ranges, complement).map(|ranges| {
+            Mode::Bytes(
+                ranges,
+                Options {
+                    out_delim: Some(
+                        matches
+                            .value_of(options::OUTPUT_DELIMITER)
+                            .unwrap_or_default()
+                            .to_owned(),
+                    ),
+                    zero_terminated: matches.is_present(options::ZERO_TERMINATED),
+                },
+            )
+        }),
+        (None, Some(char_ranges), None) => list_to_ranges(char_ranges, complement).map(|ranges| {
+            Mode::Characters(
+                ranges,
+                Options {
+                    out_delim: Some(
+                        matches
+                            .value_of(options::OUTPUT_DELIMITER)
+                            .unwrap_or_default()
+                            .to_owned(),
+                    ),
+                    zero_terminated: matches.is_present(options::ZERO_TERMINATED),
+                },
+            )
+        }),
         (None, None, Some(field_ranges)) => {
-            list_to_ranges(&field_ranges[..], complement).and_then(|ranges| {
+            list_to_ranges(field_ranges, complement).and_then(|ranges| {
                 let out_delim = match matches.value_of(options::OUTPUT_DELIMITER) {
                     Some(s) => {
                         if s.is_empty() {
diff --git a/src/uu/df/src/df.rs b/src/uu/df/src/df.rs
index 57caf7970..e898b187c 100644
--- a/src/uu/df/src/df.rs
+++ b/src/uu/df/src/df.rs
@@ -116,7 +116,6 @@ struct Options {
     show_listed_fs: bool,
     show_fs_type: bool,
     show_inode_instead: bool,
-    print_grand_total: bool,
     // block_size: usize,
     human_readable_base: i64,
     fs_selector: FsSelector,
@@ -286,7 +285,6 @@ impl Options {
             show_listed_fs: false,
             show_fs_type: false,
             show_inode_instead: false,
-            print_grand_total: false,
             // block_size: match env::var("BLOCKSIZE") {
             //     Ok(size) => size.parse().unwrap(),
             //     Err(_) => 512,
@@ -871,9 +869,6 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     if matches.is_present(OPT_ALL) {
         opt.show_all_fs = true;
     }
-    if matches.is_present(OPT_TOTAL) {
-        opt.print_grand_total = true;
-    }
     if matches.is_present(OPT_INODES) {
         opt.show_inode_instead = true;
     }
diff --git a/src/uu/du/src/du.rs b/src/uu/du/src/du.rs
index 615b66a4e..07635881a 100644
--- a/src/uu/du/src/du.rs
+++ b/src/uu/du/src/du.rs
@@ -322,7 +322,7 @@ fn convert_size_human(size: u64, multiplier: u64, _block_size: u64) -> String {
         }
     }
     if size == 0 {
-        return format!("0");
+        return "0".to_string();
     }
     format!("{}B", size)
 }
diff --git a/src/uu/expr/src/expr.rs b/src/uu/expr/src/expr.rs
index fee85dfe1..4a13812d3 100644
--- a/src/uu/expr/src/expr.rs
+++ b/src/uu/expr/src/expr.rs
@@ -51,7 +51,7 @@ fn print_expr_error(expr_error: &str) -> ! {
     crash!(2, "{}", expr_error)
 }
 
-fn evaluate_ast(maybe_ast: Result<Box<syntax_tree::ASTNode>, String>) -> Result<String, String> {
+fn evaluate_ast(maybe_ast: Result<Box<syntax_tree::AstNode>, String>) -> Result<String, String> {
     if maybe_ast.is_err() {
         Err(maybe_ast.err().unwrap())
     } else {
diff --git a/src/uu/expr/src/syntax_tree.rs b/src/uu/expr/src/syntax_tree.rs
index 3381c29bd..c81adf0c8 100644
--- a/src/uu/expr/src/syntax_tree.rs
+++ b/src/uu/expr/src/syntax_tree.rs
@@ -17,10 +17,10 @@ use onig::{Regex, RegexOptions, Syntax};
 use crate::tokens::Token;
 
 type TokenStack = Vec<(usize, Token)>;
-pub type OperandsList = Vec<Box<ASTNode>>;
+pub type OperandsList = Vec<Box<AstNode>>;
 
 #[derive(Debug)]
-pub enum ASTNode {
+pub enum AstNode {
     Leaf {
         token_idx: usize,
         value: String,
@@ -31,7 +31,7 @@ pub enum ASTNode {
         operands: OperandsList,
     },
 }
-impl ASTNode {
+impl AstNode {
     fn debug_dump(&self) {
         self.debug_dump_impl(1);
     }
@@ -40,7 +40,7 @@ impl ASTNode {
             print!("\t",);
         }
         match *self {
-            ASTNode::Leaf {
+            AstNode::Leaf {
                 ref token_idx,
                 ref value,
             } => println!(
@@ -49,7 +49,7 @@ impl ASTNode {
                 token_idx,
                 self.evaluate()
             ),
-            ASTNode::Node {
+            AstNode::Node {
                 ref token_idx,
                 ref op_type,
                 ref operands,
@@ -67,23 +67,23 @@ impl ASTNode {
         }
     }
 
-    fn new_node(token_idx: usize, op_type: &str, operands: OperandsList) -> Box<ASTNode> {
-        Box::new(ASTNode::Node {
+    fn new_node(token_idx: usize, op_type: &str, operands: OperandsList) -> Box<AstNode> {
+        Box::new(AstNode::Node {
             token_idx,
             op_type: op_type.into(),
             operands,
         })
     }
-    fn new_leaf(token_idx: usize, value: &str) -> Box<ASTNode> {
-        Box::new(ASTNode::Leaf {
+    fn new_leaf(token_idx: usize, value: &str) -> Box<AstNode> {
+        Box::new(AstNode::Leaf {
             token_idx,
             value: value.into(),
         })
     }
     pub fn evaluate(&self) -> Result<String, String> {
         match *self {
-            ASTNode::Leaf { ref value, .. } => Ok(value.clone()),
-            ASTNode::Node { ref op_type, .. } => match self.operand_values() {
+            AstNode::Leaf { ref value, .. } => Ok(value.clone()),
+            AstNode::Node { ref op_type, .. } => match self.operand_values() {
                 Err(reason) => Err(reason),
                 Ok(operand_values) => match op_type.as_ref() {
                     "+" => infix_operator_two_ints(
@@ -161,7 +161,7 @@ impl ASTNode {
         }
     }
     pub fn operand_values(&self) -> Result<Vec<String>, String> {
-        if let ASTNode::Node { ref operands, .. } = *self {
+        if let AstNode::Node { ref operands, .. } = *self {
             let mut out = Vec::with_capacity(operands.len());
             for operand in operands {
                 match operand.evaluate() {
@@ -178,7 +178,7 @@ impl ASTNode {
 
 pub fn tokens_to_ast(
     maybe_tokens: Result<Vec<(usize, Token)>, String>,
-) -> Result<Box<ASTNode>, String> {
+) -> Result<Box<AstNode>, String> {
     if maybe_tokens.is_err() {
         Err(maybe_tokens.err().unwrap())
     } else {
@@ -212,7 +212,7 @@ pub fn tokens_to_ast(
     }
 }
 
-fn maybe_dump_ast(result: &Result<Box<ASTNode>, String>) {
+fn maybe_dump_ast(result: &Result<Box<AstNode>, String>) {
     use std::env;
     if let Ok(debug_var) = env::var("EXPR_DEBUG_AST") {
         if debug_var == "1" {
@@ -238,11 +238,11 @@ fn maybe_dump_rpn(rpn: &TokenStack) {
     }
 }
 
-fn ast_from_rpn(rpn: &mut TokenStack) -> Result<Box<ASTNode>, String> {
+fn ast_from_rpn(rpn: &mut TokenStack) -> Result<Box<AstNode>, String> {
     match rpn.pop() {
         None => Err("syntax error (premature end of expression)".to_owned()),
 
-        Some((token_idx, Token::Value { value })) => Ok(ASTNode::new_leaf(token_idx, &value)),
+        Some((token_idx, Token::Value { value })) => Ok(AstNode::new_leaf(token_idx, &value)),
 
         Some((token_idx, Token::InfixOp { value, .. })) => {
             maybe_ast_node(token_idx, &value, 2, rpn)
@@ -262,7 +262,7 @@ fn maybe_ast_node(
     op_type: &str,
     arity: usize,
     rpn: &mut TokenStack,
-) -> Result<Box<ASTNode>, String> {
+) -> Result<Box<AstNode>, String> {
     let mut operands = Vec::with_capacity(arity);
     for _ in 0..arity {
         match ast_from_rpn(rpn) {
@@ -271,7 +271,7 @@ fn maybe_ast_node(
         }
     }
     operands.reverse();
-    Ok(ASTNode::new_node(token_idx, op_type, operands))
+    Ok(AstNode::new_node(token_idx, op_type, operands))
 }
 
 fn move_rest_of_ops_to_out(
diff --git a/src/uu/fmt/src/parasplit.rs b/src/uu/fmt/src/parasplit.rs
index f74a25413..950b3f66d 100644
--- a/src/uu/fmt/src/parasplit.rs
+++ b/src/uu/fmt/src/parasplit.rs
@@ -267,7 +267,7 @@ impl<'a> ParagraphStream<'a> {
                 #[allow(clippy::match_like_matches_macro)]
                 // `matches!(...)` macro not stabilized until rust v1.42
                 l_slice[..colon_posn].chars().all(|x| match x as usize {
-                    y if y < 33 || y > 126 => false,
+                    y if !(33..=126).contains(&y) => false,
                     _ => true,
                 })
             }
diff --git a/src/uu/fold/src/fold.rs b/src/uu/fold/src/fold.rs
index c35e996f2..fa703eade 100644
--- a/src/uu/fold/src/fold.rs
+++ b/src/uu/fold/src/fold.rs
@@ -66,7 +66,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
                 .takes_value(true),
         )
         .arg(Arg::with_name(options::FILE).hidden(true).multiple(true))
-        .get_matches_from(args.clone());
+        .get_matches_from(args);
 
     let bytes = matches.is_present(options::BYTES);
     let spaces = matches.is_present(options::SPACES);
diff --git a/src/uu/hashsum/src/hashsum.rs b/src/uu/hashsum/src/hashsum.rs
index ee7d2a0f7..2e31ddd25 100644
--- a/src/uu/hashsum/src/hashsum.rs
+++ b/src/uu/hashsum/src/hashsum.rs
@@ -78,7 +78,7 @@ fn detect_algo<'a>(
         "sha512sum" => ("SHA512", Box::new(Sha512::new()) as Box<dyn Digest>, 512),
         "b2sum" => ("BLAKE2", Box::new(Blake2b::new(64)) as Box<dyn Digest>, 512),
         "sha3sum" => match matches.value_of("bits") {
-            Some(bits_str) => match usize::from_str_radix(&bits_str, 10) {
+            Some(bits_str) => match (&bits_str).parse::<usize>() {
                 Ok(224) => (
                     "SHA3-224",
                     Box::new(Sha3_224::new()) as Box<dyn Digest>,
@@ -128,7 +128,7 @@ fn detect_algo<'a>(
             512,
         ),
         "shake128sum" => match matches.value_of("bits") {
-            Some(bits_str) => match usize::from_str_radix(&bits_str, 10) {
+            Some(bits_str) => match (&bits_str).parse::<usize>() {
                 Ok(bits) => (
                     "SHAKE128",
                     Box::new(Shake128::new()) as Box<dyn Digest>,
@@ -139,7 +139,7 @@ fn detect_algo<'a>(
             None => crash!(1, "--bits required for SHAKE-128"),
         },
         "shake256sum" => match matches.value_of("bits") {
-            Some(bits_str) => match usize::from_str_radix(&bits_str, 10) {
+            Some(bits_str) => match (&bits_str).parse::<usize>() {
                 Ok(bits) => (
                     "SHAKE256",
                     Box::new(Shake256::new()) as Box<dyn Digest>,
@@ -182,7 +182,7 @@ fn detect_algo<'a>(
                 }
                 if matches.is_present("sha3") {
                     match matches.value_of("bits") {
-                        Some(bits_str) => match usize::from_str_radix(&bits_str, 10) {
+                        Some(bits_str) => match (&bits_str).parse::<usize>() {
                             Ok(224) => set_or_crash(
                                 "SHA3-224",
                                 Box::new(Sha3_224::new()) as Box<dyn Digest>,
@@ -226,7 +226,7 @@ fn detect_algo<'a>(
                 }
                 if matches.is_present("shake128") {
                     match matches.value_of("bits") {
-                        Some(bits_str) => match usize::from_str_radix(&bits_str, 10) {
+                        Some(bits_str) => match (&bits_str).parse::<usize>() {
                             Ok(bits) => set_or_crash("SHAKE128", Box::new(Shake128::new()), bits),
                             Err(err) => crash!(1, "{}", err),
                         },
@@ -235,7 +235,7 @@ fn detect_algo<'a>(
                 }
                 if matches.is_present("shake256") {
                     match matches.value_of("bits") {
-                        Some(bits_str) => match usize::from_str_radix(&bits_str, 10) {
+                        Some(bits_str) => match (&bits_str).parse::<usize>() {
                             Ok(bits) => set_or_crash("SHAKE256", Box::new(Shake256::new()), bits),
                             Err(err) => crash!(1, "{}", err),
                         },
@@ -253,7 +253,7 @@ fn detect_algo<'a>(
 
 // TODO: return custom error type
 fn parse_bit_num(arg: &str) -> Result<usize, ParseIntError> {
-    usize::from_str_radix(arg, 10)
+    arg.parse()
 }
 
 fn is_valid_bit_num(arg: String) -> Result<(), String> {
diff --git a/src/uu/head/src/head.rs b/src/uu/head/src/head.rs
index 3500af544..807d04314 100644
--- a/src/uu/head/src/head.rs
+++ b/src/uu/head/src/head.rs
@@ -625,7 +625,7 @@ mod tests {
         assert_eq!(arg_outputs("head"), Ok("head".to_owned()));
     }
     #[test]
-    #[cfg(linux)]
+    #[cfg(target_os = "linux")]
     fn test_arg_iterate_bad_encoding() {
         let invalid = unsafe { std::str::from_utf8_unchecked(b"\x80\x81") };
         // this arises from a conversion from OsString to &str
diff --git a/src/uu/install/src/install.rs b/src/uu/install/src/install.rs
index e902862a8..a75ce45be 100644
--- a/src/uu/install/src/install.rs
+++ b/src/uu/install/src/install.rs
@@ -302,7 +302,7 @@ fn behavior(matches: &ArgMatches) -> Result<Behavior, i32> {
 
     let specified_mode: Option<u32> = if matches.is_present(OPT_MODE) {
         match matches.value_of(OPT_MODE) {
-            Some(x) => match mode::parse(&x[..], considering_dir) {
+            Some(x) => match mode::parse(x, considering_dir) {
                 Ok(y) => Some(y),
                 Err(err) => {
                     show_error!("Invalid mode string: {}", err);
@@ -429,7 +429,7 @@ fn standard(paths: Vec<String>, b: Behavior) -> i32 {
 /// _files_ must all exist as non-directories.
 /// _target_dir_ must be a directory.
 ///
-fn copy_files_into_dir(files: &[PathBuf], target_dir: &PathBuf, b: &Behavior) -> i32 {
+fn copy_files_into_dir(files: &[PathBuf], target_dir: &Path, b: &Behavior) -> i32 {
     if !target_dir.is_dir() {
         show_error!("target '{}' is not a directory", target_dir.display());
         return 1;
@@ -453,7 +453,7 @@ fn copy_files_into_dir(files: &[PathBuf], target_dir: &PathBuf, b: &Behavior) ->
             continue;
         }
 
-        let mut targetpath = target_dir.clone().to_path_buf();
+        let mut targetpath = target_dir.to_path_buf();
         let filename = sourcepath.components().last().unwrap();
         targetpath.push(filename);
 
@@ -478,7 +478,7 @@ fn copy_files_into_dir(files: &[PathBuf], target_dir: &PathBuf, b: &Behavior) ->
 /// _file_ must exist as a non-directory.
 /// _target_ must be a non-directory
 ///
-fn copy_file_to_file(file: &PathBuf, target: &PathBuf, b: &Behavior) -> i32 {
+fn copy_file_to_file(file: &Path, target: &Path, b: &Behavior) -> i32 {
     if copy(file, &target, b).is_err() {
         1
     } else {
@@ -497,7 +497,7 @@ fn copy_file_to_file(file: &PathBuf, target: &PathBuf, b: &Behavior) -> i32 {
 ///
 /// If the copy system call fails, we print a verbose error and return an empty error value.
 ///
-fn copy(from: &PathBuf, to: &PathBuf, b: &Behavior) -> Result<(), ()> {
+fn copy(from: &Path, to: &Path, b: &Behavior) -> Result<(), ()> {
     if b.compare && !need_copy(from, to, b) {
         return Ok(());
     }
@@ -556,7 +556,7 @@ fn copy(from: &PathBuf, to: &PathBuf, b: &Behavior) -> Result<(), ()> {
         };
         let gid = meta.gid();
         match wrap_chown(
-            to.as_path(),
+            to,
             &meta,
             Some(owner_id),
             Some(gid),
@@ -582,7 +582,7 @@ fn copy(from: &PathBuf, to: &PathBuf, b: &Behavior) -> Result<(), ()> {
             Ok(g) => g,
             _ => crash!(1, "no such group: {}", b.group),
         };
-        match wrap_chgrp(to.as_path(), &meta, group_id, false, Verbosity::Normal) {
+        match wrap_chgrp(to, &meta, group_id, false, Verbosity::Normal) {
             Ok(n) => {
                 if !n.is_empty() {
                     show_info!("{}", n);
@@ -601,7 +601,7 @@ fn copy(from: &PathBuf, to: &PathBuf, b: &Behavior) -> Result<(), ()> {
         let modified_time = FileTime::from_last_modification_time(&meta);
         let accessed_time = FileTime::from_last_access_time(&meta);
 
-        match set_file_times(to.as_path(), accessed_time, modified_time) {
+        match set_file_times(to, accessed_time, modified_time) {
             Ok(_) => {}
             Err(e) => show_info!("{}", e),
         }
@@ -630,7 +630,7 @@ fn copy(from: &PathBuf, to: &PathBuf, b: &Behavior) -> Result<(), ()> {
 ///
 /// Crashes the program if a nonexistent owner or group is specified in _b_.
 ///
-fn need_copy(from: &PathBuf, to: &PathBuf, b: &Behavior) -> bool {
+fn need_copy(from: &Path, to: &Path, b: &Behavior) -> bool {
     let from_meta = match fs::metadata(from) {
         Ok(meta) => meta,
         Err(_) => return true,
diff --git a/src/uu/ln/src/ln.rs b/src/uu/ln/src/ln.rs
index 96a0df813..04358a415 100644
--- a/src/uu/ln/src/ln.rs
+++ b/src/uu/ln/src/ln.rs
@@ -303,7 +303,7 @@ fn exec(files: &[PathBuf], settings: &Settings) -> i32 {
     }
 }
 
-fn link_files_in_dir(files: &[PathBuf], target_dir: &PathBuf, settings: &Settings) -> i32 {
+fn link_files_in_dir(files: &[PathBuf], target_dir: &Path, settings: &Settings) -> i32 {
     if !target_dir.is_dir() {
         show_error!("target '{}' is not a directory", target_dir.display());
         return 1;
@@ -329,7 +329,7 @@ fn link_files_in_dir(files: &[PathBuf], target_dir: &PathBuf, settings: &Setting
                     };
                 }
             }
-            target_dir.clone()
+            target_dir.to_path_buf()
         } else {
             match srcpath.as_os_str().to_str() {
                 Some(name) => {
@@ -370,7 +370,7 @@ fn link_files_in_dir(files: &[PathBuf], target_dir: &PathBuf, settings: &Setting
     }
 }
 
-fn relative_path<'a>(src: &PathBuf, dst: &PathBuf) -> Result<Cow<'a, Path>> {
+fn relative_path<'a>(src: &Path, dst: &Path) -> Result<Cow<'a, Path>> {
     let abssrc = canonicalize(src, CanonicalizeMode::Normal)?;
     let absdst = canonicalize(dst, CanonicalizeMode::Normal)?;
     let suffix_pos = abssrc
@@ -390,7 +390,7 @@ fn relative_path<'a>(src: &PathBuf, dst: &PathBuf) -> Result<Cow<'a, Path>> {
     Ok(result.into())
 }
 
-fn link(src: &PathBuf, dst: &PathBuf, settings: &Settings) -> Result<()> {
+fn link(src: &Path, dst: &Path, settings: &Settings) -> Result<()> {
     let mut backup_path = None;
     let source: Cow<'_, Path> = if settings.relative {
         relative_path(&src, dst)?
@@ -453,13 +453,13 @@ fn read_yes() -> bool {
     }
 }
 
-fn simple_backup_path(path: &PathBuf, suffix: &str) -> PathBuf {
+fn simple_backup_path(path: &Path, suffix: &str) -> PathBuf {
     let mut p = path.as_os_str().to_str().unwrap().to_owned();
     p.push_str(suffix);
     PathBuf::from(p)
 }
 
-fn numbered_backup_path(path: &PathBuf) -> PathBuf {
+fn numbered_backup_path(path: &Path) -> PathBuf {
     let mut i: u64 = 1;
     loop {
         let new_path = simple_backup_path(path, &format!(".~{}~", i));
@@ -470,7 +470,7 @@ fn numbered_backup_path(path: &PathBuf) -> PathBuf {
     }
 }
 
-fn existing_backup_path(path: &PathBuf, suffix: &str) -> PathBuf {
+fn existing_backup_path(path: &Path, suffix: &str) -> PathBuf {
     let test_path = simple_backup_path(path, &".~1~".to_owned());
     if test_path.exists() {
         return numbered_backup_path(path);
diff --git a/src/uu/ls/src/ls.rs b/src/uu/ls/src/ls.rs
index fdc11144a..aebaa6b44 100644
--- a/src/uu/ls/src/ls.rs
+++ b/src/uu/ls/src/ls.rs
@@ -370,6 +370,7 @@ impl Config {
             })
             .or_else(|| termsize::get().map(|s| s.cols));
 
+        #[allow(clippy::needless_bool)]
         let show_control = if options.is_present(options::HIDE_CONTROL_CHARS) {
             false
         } else if options.is_present(options::SHOW_CONTROL_CHARS) {
@@ -1042,7 +1043,7 @@ fn sort_entries(entries: &mut Vec<PathBuf>, config: &Config) {
             .sort_by_key(|k| Reverse(get_metadata(k, config).map(|md| md.len()).unwrap_or(0))),
         // The default sort in GNU ls is case insensitive
         Sort::Name => entries.sort_by_key(|k| k.to_string_lossy().to_lowercase()),
-        Sort::Version => entries.sort_by(version_cmp::version_cmp),
+        Sort::Version => entries.sort_by(|a, b| version_cmp::version_cmp(a, b)),
         Sort::None => {}
     }
 
@@ -1076,7 +1077,7 @@ fn should_display(entry: &DirEntry, config: &Config) -> bool {
     true
 }
 
-fn enter_directory(dir: &PathBuf, config: &Config) {
+fn enter_directory(dir: &Path, config: &Config) {
     let mut entries: Vec<_> = safe_unwrap!(fs::read_dir(dir).and_then(Iterator::collect));
 
     entries.retain(|e| should_display(e, config));
@@ -1101,7 +1102,7 @@ fn enter_directory(dir: &PathBuf, config: &Config) {
     }
 }
 
-fn get_metadata(entry: &PathBuf, config: &Config) -> std::io::Result<Metadata> {
+fn get_metadata(entry: &Path, config: &Config) -> std::io::Result<Metadata> {
     if config.dereference {
         entry.metadata().or_else(|_| entry.symlink_metadata())
     } else {
@@ -1109,7 +1110,7 @@ fn get_metadata(entry: &PathBuf, config: &Config) -> std::io::Result<Metadata> {
     }
 }
 
-fn display_dir_entry_size(entry: &PathBuf, config: &Config) -> (usize, usize) {
+fn display_dir_entry_size(entry: &Path, config: &Config) -> (usize, usize) {
     if let Ok(md) = get_metadata(entry, config) {
         (
             display_symlink_count(&md).len(),
@@ -1204,7 +1205,7 @@ fn display_grid(names: impl Iterator<Item = Cell>, width: u16, direction: Direct
 use uucore::fs::display_permissions;
 
 fn display_item_long(
-    item: &PathBuf,
+    item: &Path,
     strip: Option<&Path>,
     max_links: usize,
     max_size: usize,
diff --git a/src/uu/ls/src/version_cmp.rs b/src/uu/ls/src/version_cmp.rs
index 3cd5989f1..4cd39f916 100644
--- a/src/uu/ls/src/version_cmp.rs
+++ b/src/uu/ls/src/version_cmp.rs
@@ -1,8 +1,9 @@
-use std::{cmp::Ordering, path::PathBuf};
+use std::cmp::Ordering;
+use std::path::Path;
 
-/// Compare pathbufs in a way that matches the GNU version sort, meaning that
+/// Compare paths in a way that matches the GNU version sort, meaning that
 /// numbers get sorted in a natural way.
-pub(crate) fn version_cmp(a: &PathBuf, b: &PathBuf) -> Ordering {
+pub(crate) fn version_cmp(a: &Path, b: &Path) -> Ordering {
     let a_string = a.to_string_lossy();
     let b_string = b.to_string_lossy();
     let mut a = a_string.chars().peekable();
diff --git a/src/uu/mv/src/mv.rs b/src/uu/mv/src/mv.rs
index b481aeebc..f57178a09 100644
--- a/src/uu/mv/src/mv.rs
+++ b/src/uu/mv/src/mv.rs
@@ -335,7 +335,7 @@ fn exec(files: &[PathBuf], b: Behavior) -> i32 {
     0
 }
 
-fn move_files_into_dir(files: &[PathBuf], target_dir: &PathBuf, b: &Behavior) -> i32 {
+fn move_files_into_dir(files: &[PathBuf], target_dir: &Path, b: &Behavior) -> i32 {
     if !target_dir.is_dir() {
         show_error!("target ‘{}’ is not a directory", target_dir.display());
         return 1;
@@ -373,7 +373,7 @@ fn move_files_into_dir(files: &[PathBuf], target_dir: &PathBuf, b: &Behavior) ->
     }
 }
 
-fn rename(from: &PathBuf, to: &PathBuf, b: &Behavior) -> io::Result<()> {
+fn rename(from: &Path, to: &Path, b: &Behavior) -> io::Result<()> {
     let mut backup_path = None;
 
     if to.exists() {
@@ -429,7 +429,7 @@ fn rename(from: &PathBuf, to: &PathBuf, b: &Behavior) -> io::Result<()> {
 
 /// A wrapper around `fs::rename`, so that if it fails, we try falling back on
 /// copying and removing.
-fn rename_with_fallback(from: &PathBuf, to: &PathBuf) -> io::Result<()> {
+fn rename_with_fallback(from: &Path, to: &Path) -> io::Result<()> {
     if fs::rename(from, to).is_err() {
         // Get metadata without following symlinks
         let metadata = from.symlink_metadata()?;
@@ -464,7 +464,7 @@ fn rename_with_fallback(from: &PathBuf, to: &PathBuf) -> io::Result<()> {
 /// Move the given symlink to the given destination. On Windows, dangling
 /// symlinks return an error.
 #[inline]
-fn rename_symlink_fallback(from: &PathBuf, to: &PathBuf) -> io::Result<()> {
+fn rename_symlink_fallback(from: &Path, to: &Path) -> io::Result<()> {
     let path_symlink_points_to = fs::read_link(from)?;
     #[cfg(unix)]
     {
@@ -507,20 +507,20 @@ fn read_yes() -> bool {
     }
 }
 
-fn simple_backup_path(path: &PathBuf, suffix: &str) -> PathBuf {
+fn simple_backup_path(path: &Path, suffix: &str) -> PathBuf {
     let mut p = path.to_string_lossy().into_owned();
     p.push_str(suffix);
     PathBuf::from(p)
 }
 
-fn numbered_backup_path(path: &PathBuf) -> PathBuf {
+fn numbered_backup_path(path: &Path) -> PathBuf {
     (1_u64..)
         .map(|i| path.with_extension(format!("~{}~", i)))
         .find(|p| !p.exists())
         .expect("cannot create backup")
 }
 
-fn existing_backup_path(path: &PathBuf, suffix: &str) -> PathBuf {
+fn existing_backup_path(path: &Path, suffix: &str) -> PathBuf {
     let test_path = path.with_extension("~1~");
     if test_path.exists() {
         numbered_backup_path(path)
@@ -529,7 +529,7 @@ fn existing_backup_path(path: &PathBuf, suffix: &str) -> PathBuf {
     }
 }
 
-fn is_empty_dir(path: &PathBuf) -> bool {
+fn is_empty_dir(path: &Path) -> bool {
     match fs::read_dir(path) {
         Ok(contents) => contents.peekable().peek().is_none(),
         Err(_e) => false,
diff --git a/src/uu/od/src/od.rs b/src/uu/od/src/od.rs
index c3b39fca1..36eae66ab 100644
--- a/src/uu/od/src/od.rs
+++ b/src/uu/od/src/od.rs
@@ -118,7 +118,7 @@ struct OdOptions {
 }
 
 impl OdOptions {
-    fn new<'a>(matches: ArgMatches<'a>, args: Vec<String>) -> Result<OdOptions, String> {
+    fn new(matches: ArgMatches, args: Vec<String>) -> Result<OdOptions, String> {
         let byte_order = match matches.value_of(options::ENDIAN) {
             None => ByteOrder::Native,
             Some("little") => ByteOrder::Little,
diff --git a/src/uu/od/src/parse_inputs.rs b/src/uu/od/src/parse_inputs.rs
index 915aa1d92..533f4f106 100644
--- a/src/uu/od/src/parse_inputs.rs
+++ b/src/uu/od/src/parse_inputs.rs
@@ -63,7 +63,7 @@ pub fn parse_inputs(matches: &dyn CommandLineOpts) -> Result<CommandLineInputs,
                 }
                 if input_strings.len() == 2 {
                     return Ok(CommandLineInputs::FileAndOffset((
-                        input_strings[0].clone().to_owned(),
+                        input_strings[0].to_string(),
                         n,
                         None,
                     )));
@@ -106,7 +106,7 @@ pub fn parse_inputs_traditional(input_strings: Vec<&str>) -> Result<CommandLineI
                     Some(m),
                 ))),
                 (_, Ok(m)) => Ok(CommandLineInputs::FileAndOffset((
-                    input_strings[0].clone().to_owned(),
+                    input_strings[0].to_string(),
                     m,
                     None,
                 ))),
@@ -118,7 +118,7 @@ pub fn parse_inputs_traditional(input_strings: Vec<&str>) -> Result<CommandLineI
             let label = parse_offset_operand(&input_strings[2]);
             match (offset, label) {
                 (Ok(n), Ok(m)) => Ok(CommandLineInputs::FileAndOffset((
-                    input_strings[0].clone().to_owned(),
+                    input_strings[0].to_string(),
                     n,
                     Some(m),
                 ))),
diff --git a/src/uu/pinky/src/pinky.rs b/src/uu/pinky/src/pinky.rs
index 772e311d6..851a3cd42 100644
--- a/src/uu/pinky/src/pinky.rs
+++ b/src/uu/pinky/src/pinky.rs
@@ -15,7 +15,6 @@ use uucore::utmpx::{self, time, Utmpx};
 
 use std::io::prelude::*;
 use std::io::BufReader;
-use std::io::Result as IOResult;
 
 use std::fs::File;
 use std::os::unix::fs::MetadataExt;
@@ -136,12 +135,8 @@ The utmp file will be {}",
     };
 
     if do_short_format {
-        if let Err(e) = pk.short_pinky() {
-            show_usage_error!("{}", e);
-            1
-        } else {
-            0
-        }
+        pk.short_pinky();
+        0
     } else {
         pk.long_pinky()
     }
@@ -282,7 +277,7 @@ impl Pinky {
         println!();
     }
 
-    fn short_pinky(&self) -> IOResult<()> {
+    fn short_pinky(&self) {
         if self.include_heading {
             self.print_heading();
         }
@@ -295,7 +290,6 @@ impl Pinky {
                 }
             }
         }
-        Ok(())
     }
 
     fn long_pinky(&self) -> i32 {
diff --git a/src/uu/printf/src/tokenize/num_format/formatters/base_conv/mod.rs b/src/uu/printf/src/tokenize/num_format/formatters/base_conv/mod.rs
index 79af9abd5..04d33b52c 100644
--- a/src/uu/printf/src/tokenize/num_format/formatters/base_conv/mod.rs
+++ b/src/uu/printf/src/tokenize/num_format/formatters/base_conv/mod.rs
@@ -199,8 +199,7 @@ pub fn arrnum_int_add(arrnum: &[u8], basenum: u8, base_ten_int_term: u8) -> Vec<
 }
 
 pub fn base_conv_vec(src: &[u8], radix_src: u8, radix_dest: u8) -> Vec<u8> {
-    let mut result: Vec<u8> = Vec::new();
-    result.push(0);
+    let mut result = vec![0];
     for i in src {
         result = arrnum_int_mult(&result, radix_dest, radix_src);
         result = arrnum_int_add(&result, radix_dest, *i);
@@ -226,8 +225,7 @@ pub fn base_conv_float(src: &[u8], radix_src: u8, radix_dest: u8) -> f64 {
     // to implement this for arbitrary string input.
     // until then, the below operates as an outline
     // of how it would work.
-    let mut result: Vec<u8> = Vec::new();
-    result.push(0);
+    let result: Vec<u8> = vec![0];
     let mut factor: f64 = 1_f64;
     let radix_src_float: f64 = f64::from(radix_src);
     let mut r: f64 = 0_f64;
diff --git a/src/uu/printf/src/tokenize/num_format/num_format.rs b/src/uu/printf/src/tokenize/num_format/num_format.rs
index 9a519e95e..812f51b5a 100644
--- a/src/uu/printf/src/tokenize/num_format/num_format.rs
+++ b/src/uu/printf/src/tokenize/num_format/num_format.rs
@@ -263,9 +263,5 @@ pub fn num_format(field: &FormatField, in_str_opt: Option<&String>) -> Option<St
         };
     // if we have a formatPrimitive, print its results
     // according to the field-char appropriate Formatter
-    if let Some(prim) = prim_opt {
-        Some(fmtr.primitive_to_str(&prim, field.clone()))
-    } else {
-        None
-    }
+    prim_opt.map(|prim| fmtr.primitive_to_str(&prim, field.clone()))
 }
diff --git a/src/uu/ptx/src/ptx.rs b/src/uu/ptx/src/ptx.rs
index 38327e4e3..69b3f7aa1 100644
--- a/src/uu/ptx/src/ptx.rs
+++ b/src/uu/ptx/src/ptx.rs
@@ -177,14 +177,14 @@ fn get_config(matches: &clap::ArgMatches) -> Config {
     }
     if matches.is_present(options::WIDTH) {
         let width_str = matches.value_of(options::WIDTH).expect(err_msg).to_string();
-        config.line_width = crash_if_err!(1, usize::from_str_radix(&width_str, 10));
+        config.line_width = crash_if_err!(1, (&width_str).parse::<usize>());
     }
     if matches.is_present(options::GAP_SIZE) {
         let gap_str = matches
             .value_of(options::GAP_SIZE)
             .expect(err_msg)
             .to_string();
-        config.gap_size = crash_if_err!(1, usize::from_str_radix(&gap_str, 10));
+        config.gap_size = crash_if_err!(1, (&gap_str).parse::<usize>());
     }
     if matches.is_present(options::FORMAT_ROFF) {
         config.format = OutFormat::Roff;
diff --git a/src/uu/readlink/src/readlink.rs b/src/uu/readlink/src/readlink.rs
index 727c2cce5..43a4ca656 100644
--- a/src/uu/readlink/src/readlink.rs
+++ b/src/uu/readlink/src/readlink.rs
@@ -13,7 +13,7 @@ extern crate uucore;
 use clap::{App, Arg};
 use std::fs;
 use std::io::{stdout, Write};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use uucore::fs::{canonicalize, CanonicalizeMode};
 
 const NAME: &str = "readlink";
@@ -160,8 +160,8 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     0
 }
 
-fn show(path: &PathBuf, no_newline: bool, use_zero: bool) {
-    let path = path.as_path().to_str().unwrap();
+fn show(path: &Path, no_newline: bool, use_zero: bool) {
+    let path = path.to_str().unwrap();
     if use_zero {
         print!("{}\0", path);
     } else if no_newline {
diff --git a/src/uu/realpath/src/realpath.rs b/src/uu/realpath/src/realpath.rs
index 5cc8f3d9a..37ff70fb2 100644
--- a/src/uu/realpath/src/realpath.rs
+++ b/src/uu/realpath/src/realpath.rs
@@ -12,7 +12,7 @@ extern crate uucore;
 
 use clap::{App, Arg};
 use std::fs;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use uucore::fs::{canonicalize, CanonicalizeMode};
 
 static ABOUT: &str = "print the resolved path";
@@ -82,7 +82,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     retcode
 }
 
-fn resolve_path(p: &PathBuf, strip: bool, zero: bool, quiet: bool) -> bool {
+fn resolve_path(p: &Path, strip: bool, zero: bool, quiet: bool) -> bool {
     let abs = canonicalize(p, CanonicalizeMode::Normal).unwrap();
 
     if strip {
diff --git a/src/uu/rm/src/rm.rs b/src/uu/rm/src/rm.rs
index 09671768b..94626b4e7 100644
--- a/src/uu/rm/src/rm.rs
+++ b/src/uu/rm/src/rm.rs
@@ -176,7 +176,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
                 } else if matches.is_present(OPT_PROMPT_MORE) {
                     InteractiveMode::Once
                 } else if matches.is_present(OPT_INTERACTIVE) {
-                    match &matches.value_of(OPT_INTERACTIVE).unwrap()[..] {
+                    match matches.value_of(OPT_INTERACTIVE).unwrap() {
                         "none" => InteractiveMode::None,
                         "once" => InteractiveMode::Once,
                         "always" => InteractiveMode::Always,
diff --git a/src/uu/seq/src/seq.rs b/src/uu/seq/src/seq.rs
index 671dd7e1c..c3bba1c78 100644
--- a/src/uu/seq/src/seq.rs
+++ b/src/uu/seq/src/seq.rs
@@ -102,7 +102,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     let mut largest_dec = 0;
     let mut padding = 0;
     let first = if numbers.len() > 1 {
-        let slice = &numbers[0][..];
+        let slice = numbers[0];
         let len = slice.len();
         let dec = slice.find('.').unwrap_or(len);
         largest_dec = len - dec;
@@ -118,7 +118,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         1.0
     };
     let increment = if numbers.len() > 2 {
-        let slice = &numbers[1][..];
+        let slice = numbers[1];
         let len = slice.len();
         let dec = slice.find('.').unwrap_or(len);
         largest_dec = cmp::max(largest_dec, len - dec);
@@ -134,11 +134,11 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         1.0
     };
     if increment == 0.0 {
-        show_error!("increment value: '{}'", &numbers[1][..]);
+        show_error!("increment value: '{}'", numbers[1]);
         return 1;
     }
     let last = {
-        let slice = &numbers[numbers.len() - 1][..];
+        let slice = numbers[numbers.len() - 1];
         padding = cmp::max(padding, slice.find('.').unwrap_or_else(|| slice.len()));
         match parse_float(slice) {
             Ok(n) => n,
diff --git a/src/uu/shred/src/shred.rs b/src/uu/shred/src/shred.rs
index 7e0e77184..b89d48a10 100644
--- a/src/uu/shred/src/shred.rs
+++ b/src/uu/shred/src/shred.rs
@@ -363,10 +363,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
 
     let force = matches.is_present(options::FORCE);
     let remove = matches.is_present(options::REMOVE);
-    let size_arg = match matches.value_of(options::SIZE) {
-        Some(s) => Some(s.to_string()),
-        None => None,
-    };
+    let size_arg = matches.value_of(options::SIZE).map(|s| s.to_string());
     let size = get_size(size_arg);
     let exact = matches.is_present(options::EXACT) && size.is_none(); // if -s is given, ignore -x
     let zero = matches.is_present(options::ZERO);
@@ -439,6 +436,7 @@ fn pass_name(pass_type: PassType) -> String {
     }
 }
 
+#[allow(clippy::too_many_arguments)]
 fn wipe_file(
     path_str: &str,
     n_passes: usize,
@@ -472,12 +470,9 @@ fn wipe_file(
 
         let mut perms = metadata.permissions();
         perms.set_readonly(false);
-        match fs::set_permissions(path, perms) {
-            Err(e) => {
-                show_error!("{}", e);
-                return;
-            }
-            _ => {}
+        if let Err(e) = fs::set_permissions(path, perms) {
+            show_error!("{}", e);
+            return;
         }
     }
 
diff --git a/src/uu/stdbuf/src/libstdbuf/src/libstdbuf.rs b/src/uu/stdbuf/src/libstdbuf/src/libstdbuf.rs
index fa36d4ab5..d08427d98 100644
--- a/src/uu/stdbuf/src/libstdbuf/src/libstdbuf.rs
+++ b/src/uu/stdbuf/src/libstdbuf/src/libstdbuf.rs
@@ -35,8 +35,8 @@ extern "C" {
 
 fn set_buffer(stream: *mut FILE, value: &str) {
     let (mode, size): (c_int, size_t) = match value {
-        "0" => (_IONBF, 0 as size_t),
-        "L" => (_IOLBF, 0 as size_t),
+        "0" => (_IONBF, 0_usize),
+        "L" => (_IOLBF, 0_usize),
         input => {
             let buff_size: usize = match input.parse() {
                 Ok(num) => num,
diff --git a/src/uu/stdbuf/src/stdbuf.rs b/src/uu/stdbuf/src/stdbuf.rs
index a6c9f9dc5..8c65a5c7e 100644
--- a/src/uu/stdbuf/src/stdbuf.rs
+++ b/src/uu/stdbuf/src/stdbuf.rs
@@ -141,12 +141,10 @@ fn parse_size(size: &str) -> Option<u64> {
 
 fn check_option(matches: &ArgMatches, name: &str) -> Result<BufferType, ProgramOptionsError> {
     match matches.value_of(name) {
-        Some(value) => match &value[..] {
+        Some(value) => match value {
             "L" => {
                 if name == options::INPUT {
-                    Err(ProgramOptionsError(format!(
-                        "line buffering stdin is meaningless"
-                    )))
+                    Err(ProgramOptionsError("line buffering stdin is meaningless".to_string()))
                 } else {
                     Ok(BufferType::Line)
                 }
diff --git a/src/uu/sum/src/sum.rs b/src/uu/sum/src/sum.rs
index ed5655a3d..d0fbc7c0d 100644
--- a/src/uu/sum/src/sum.rs
+++ b/src/uu/sum/src/sum.rs
@@ -75,7 +75,7 @@ fn open(name: &str) -> Result<Box<dyn Read>> {
                     "Is a directory",
                 ));
             };
-            if !path.metadata().is_ok() {
+            if path.metadata().is_err() {
                 return Err(std::io::Error::new(
                     std::io::ErrorKind::NotFound,
                     "No such file or directory",
diff --git a/src/uu/tac/src/tac.rs b/src/uu/tac/src/tac.rs
index 68dae94e2..666ba3384 100644
--- a/src/uu/tac/src/tac.rs
+++ b/src/uu/tac/src/tac.rs
@@ -90,7 +90,7 @@ fn tac(filenames: Vec<String>, before: bool, _: bool, separator: &str) -> i32 {
             Box::new(stdin()) as Box<dyn Read>
         } else {
             let path = Path::new(filename);
-            if path.is_dir() || !path.metadata().is_ok() {
+            if path.is_dir() || path.metadata().is_err() {
                 show_error!(
                     "failed to open '{}' for reading: No such file or directory",
                     filename
diff --git a/src/uu/test/src/test.rs b/src/uu/test/src/test.rs
index 4394e4a8e..f882ff5ae 100644
--- a/src/uu/test/src/test.rs
+++ b/src/uu/test/src/test.rs
@@ -55,16 +55,16 @@ fn two(args: &[&[u8]], error: &mut bool) -> bool {
         b"-d" => path(args[1], PathCondition::Directory),
         b"-e" => path(args[1], PathCondition::Exists),
         b"-f" => path(args[1], PathCondition::Regular),
-        b"-g" => path(args[1], PathCondition::GroupIDFlag),
+        b"-g" => path(args[1], PathCondition::GroupIdFlag),
         b"-h" => path(args[1], PathCondition::SymLink),
         b"-L" => path(args[1], PathCondition::SymLink),
         b"-n" => one(&args[1..]),
-        b"-p" => path(args[1], PathCondition::FIFO),
+        b"-p" => path(args[1], PathCondition::Fifo),
         b"-r" => path(args[1], PathCondition::Readable),
         b"-S" => path(args[1], PathCondition::Socket),
         b"-s" => path(args[1], PathCondition::NonEmpty),
         b"-t" => isatty(args[1]),
-        b"-u" => path(args[1], PathCondition::UserIDFlag),
+        b"-u" => path(args[1], PathCondition::UserIdFlag),
         b"-w" => path(args[1], PathCondition::Writable),
         b"-x" => path(args[1], PathCondition::Executable),
         b"-z" => !one(&args[1..]),
@@ -322,13 +322,13 @@ enum PathCondition {
     Directory,
     Exists,
     Regular,
-    GroupIDFlag,
+    GroupIdFlag,
     SymLink,
-    FIFO,
+    Fifo,
     Readable,
     Socket,
     NonEmpty,
-    UserIDFlag,
+    UserIdFlag,
     Writable,
     Executable,
 }
@@ -390,13 +390,13 @@ fn path(path: &[u8], cond: PathCondition) -> bool {
         PathCondition::Directory => file_type.is_dir(),
         PathCondition::Exists => true,
         PathCondition::Regular => file_type.is_file(),
-        PathCondition::GroupIDFlag => metadata.mode() & S_ISGID != 0,
+        PathCondition::GroupIdFlag => metadata.mode() & S_ISGID != 0,
         PathCondition::SymLink => metadata.file_type().is_symlink(),
-        PathCondition::FIFO => file_type.is_fifo(),
+        PathCondition::Fifo => file_type.is_fifo(),
         PathCondition::Readable => perm(metadata, Permission::Read),
         PathCondition::Socket => file_type.is_socket(),
         PathCondition::NonEmpty => metadata.size() > 0,
-        PathCondition::UserIDFlag => metadata.mode() & S_ISUID != 0,
+        PathCondition::UserIdFlag => metadata.mode() & S_ISUID != 0,
         PathCondition::Writable => perm(metadata, Permission::Write),
         PathCondition::Executable => perm(metadata, Permission::Execute),
     }
@@ -416,13 +416,13 @@ fn path(path: &[u8], cond: PathCondition) -> bool {
         PathCondition::Directory => stat.is_dir(),
         PathCondition::Exists => true,
         PathCondition::Regular => stat.is_file(),
-        PathCondition::GroupIDFlag => false,
+        PathCondition::GroupIdFlag => false,
         PathCondition::SymLink => false,
-        PathCondition::FIFO => false,
+        PathCondition::Fifo => false,
         PathCondition::Readable => false, // TODO
         PathCondition::Socket => false,
         PathCondition::NonEmpty => stat.len() > 0,
-        PathCondition::UserIDFlag => false,
+        PathCondition::UserIdFlag => false,
         PathCondition::Writable => false,   // TODO
         PathCondition::Executable => false, // TODO
     }
diff --git a/src/uu/touch/src/touch.rs b/src/uu/touch/src/touch.rs
index 39405900e..f0c3c12d2 100644
--- a/src/uu/touch/src/touch.rs
+++ b/src/uu/touch/src/touch.rs
@@ -137,7 +137,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
 
     let (mut atime, mut mtime) = if matches.is_present(options::sources::REFERENCE) {
         stat(
-            &matches.value_of(options::sources::REFERENCE).unwrap()[..],
+            matches.value_of(options::sources::REFERENCE).unwrap(),
             !matches.is_present(options::NO_DEREF),
         )
     } else if matches.is_present(options::sources::DATE)
diff --git a/src/uu/tr/src/expand.rs b/src/uu/tr/src/expand.rs
index e71cf262c..73612a065 100644
--- a/src/uu/tr/src/expand.rs
+++ b/src/uu/tr/src/expand.rs
@@ -24,7 +24,7 @@ use std::ops::RangeInclusive;
 fn parse_sequence(s: &str) -> (char, usize) {
     let c = s.chars().next().expect("invalid escape: empty string");
 
-    if '0' <= c && c <= '7' {
+    if ('0'..='7').contains(&c) {
         let mut v = c.to_digit(8).unwrap();
         let mut consumed = 1;
         let bits_per_digit = 3;
diff --git a/src/uu/tsort/src/tsort.rs b/src/uu/tsort/src/tsort.rs
index 3440972a2..967a9514a 100644
--- a/src/uu/tsort/src/tsort.rs
+++ b/src/uu/tsort/src/tsort.rs
@@ -16,8 +16,8 @@ use std::io::{stdin, BufRead, BufReader, Read};
 use std::path::Path;
 
 static VERSION: &str = env!("CARGO_PKG_VERSION");
-static SUMMARY: &str = "Topological sort the strings in FILE. 
-Strings are defined as any sequence of tokens separated by whitespace (tab, space, or newline). 
+static SUMMARY: &str = "Topological sort the strings in FILE.
+Strings are defined as any sequence of tokens separated by whitespace (tab, space, or newline).
 If FILE is not passed in, stdin is used instead.";
 static USAGE: &str = "tsort [OPTIONS] FILE";
 
@@ -32,13 +32,16 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         .version(VERSION)
         .usage(USAGE)
         .about(SUMMARY)
-        .arg(Arg::with_name(options::FILE).hidden(true))
+        .arg(
+            Arg::with_name(options::FILE)
+                .default_value("-")
+                .hidden(true),
+        )
         .get_matches_from(args);
 
-    let input = match matches.value_of(options::FILE) {
-        Some(v) => v,
-        None => "-",
-    };
+    let input = matches
+        .value_of(options::FILE)
+        .expect("Value is required by clap");
 
     let mut stdin_buf;
     let mut file_buf;
diff --git a/src/uu/tty/src/tty.rs b/src/uu/tty/src/tty.rs
index 18d69db46..815c6f96b 100644
--- a/src/uu/tty/src/tty.rs
+++ b/src/uu/tty/src/tty.rs
@@ -65,9 +65,9 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         }
     }
 
-    return if is_stdin_interactive() {
+    if is_stdin_interactive() {
         libc::EXIT_SUCCESS
     } else {
         libc::EXIT_FAILURE
-    };
+    }
 }
diff --git a/src/uu/unexpand/src/unexpand.rs b/src/uu/unexpand/src/unexpand.rs
index 5b08c33cf..3d80bd6e9 100644
--- a/src/uu/unexpand/src/unexpand.rs
+++ b/src/uu/unexpand/src/unexpand.rs
@@ -149,10 +149,8 @@ fn next_tabstop(tabstops: &[usize], col: usize) -> Option<usize> {
         Some(tabstops[0] - col % tabstops[0])
     } else {
         // find next larger tab
-        match tabstops.iter().find(|&&t| t > col) {
-            Some(t) => Some(t - col),
-            None => None, // if there isn't one in the list, tab becomes a single space
-        }
+        // if there isn't one in the list, tab becomes a single space
+        tabstops.iter().find(|&&t| t > col).map(|t| t-col)
     }
 }
 
diff --git a/src/uu/wc/src/count_bytes.rs b/src/uu/wc/src/count_bytes.rs
index 0c3b5edb7..7f06f8171 100644
--- a/src/uu/wc/src/count_bytes.rs
+++ b/src/uu/wc/src/count_bytes.rs
@@ -72,30 +72,27 @@ pub(crate) fn count_bytes_fast<T: WordCountable>(handle: &mut T) -> WcResult<usi
     #[cfg(unix)]
     {
         let fd = handle.as_raw_fd();
-        match fstat(fd) {
-            Ok(stat) => {
-                // If the file is regular, then the `st_size` should hold
-                // the file's size in bytes.
-                if (stat.st_mode & S_IFREG) != 0 {
-                    return Ok(stat.st_size as usize);
-                }
-                #[cfg(any(target_os = "linux", target_os = "android"))]
-                {
-                    // Else, if we're on Linux and our file is a FIFO pipe
-                    // (or stdin), we use splice to count the number of bytes.
-                    if (stat.st_mode & S_IFIFO) != 0 {
-                        if let Ok(n) = count_bytes_using_splice(fd) {
-                            return Ok(n);
-                        }
+        if let Ok(stat) = fstat(fd) {
+            // If the file is regular, then the `st_size` should hold
+            // the file's size in bytes.
+            if (stat.st_mode & S_IFREG) != 0 {
+                return Ok(stat.st_size as usize);
+            }
+            #[cfg(any(target_os = "linux", target_os = "android"))]
+            {
+                // Else, if we're on Linux and our file is a FIFO pipe
+                // (or stdin), we use splice to count the number of bytes.
+                if (stat.st_mode & S_IFIFO) != 0 {
+                    if let Ok(n) = count_bytes_using_splice(fd) {
+                        return Ok(n);
                     }
                 }
             }
-            _ => {}
         }
     }
 
     // Fall back on `read`, but without the overhead of counting words and lines.
-    let mut buf = [0 as u8; BUF_SIZE];
+    let mut buf = [0_u8; BUF_SIZE];
     let mut byte_count = 0;
     loop {
         match handle.read(&mut buf) {
diff --git a/src/uu/wc/src/wc.rs b/src/uu/wc/src/wc.rs
index 22463caa4..59ca10141 100644
--- a/src/uu/wc/src/wc.rs
+++ b/src/uu/wc/src/wc.rs
@@ -138,11 +138,8 @@ impl AddAssign for WordCount {
 }
 
 impl WordCount {
-    fn with_title<'a>(self, title: &'a str) -> TitledWordCount<'a> {
-        return TitledWordCount {
-            title: title,
-            count: self,
-        };
+    fn with_title(self, title: &str) -> TitledWordCount {
+        TitledWordCount { title, count: self }
     }
 }
 
@@ -251,7 +248,7 @@ fn is_word_separator(byte: u8) -> bool {
 fn word_count_from_reader<T: WordCountable>(
     mut reader: T,
     settings: &Settings,
-    path: &String,
+    path: &str,
 ) -> WcResult<WordCount> {
     let only_count_bytes = settings.show_bytes
         && (!(settings.show_chars
@@ -333,18 +330,18 @@ fn word_count_from_reader<T: WordCountable>(
     })
 }
 
-fn word_count_from_path(path: &String, settings: &Settings) -> WcResult<WordCount> {
+fn word_count_from_path(path: &str, settings: &Settings) -> WcResult<WordCount> {
     if path == "-" {
         let stdin = io::stdin();
         let stdin_lock = stdin.lock();
-        return Ok(word_count_from_reader(stdin_lock, settings, path)?);
+        word_count_from_reader(stdin_lock, settings, path)
     } else {
         let path_obj = Path::new(path);
         if path_obj.is_dir() {
-            return Err(WcError::IsDirectory(path.clone()));
+            Err(WcError::IsDirectory(path.to_owned()))
         } else {
             let file = File::open(path)?;
-            return Ok(word_count_from_reader(file, settings, path)?);
+            word_count_from_reader(file, settings, path)
         }
     }
 }
@@ -425,7 +422,7 @@ fn print_stats(
     }
 
     if result.title == "-" {
-        writeln!(stdout_lock, "")?;
+        writeln!(stdout_lock)?;
     } else {
         writeln!(stdout_lock, " {}", result.title)?;
     }
diff --git a/src/uu/who/src/who.rs b/src/uu/who/src/who.rs
index 8c7ff3211..9444985dc 100644
--- a/src/uu/who/src/who.rs
+++ b/src/uu/who/src/who.rs
@@ -222,7 +222,6 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         need_runlevel,
         need_users,
         my_line_only,
-        has_records: false,
         args: matches.free,
     };
 
@@ -247,7 +246,6 @@ struct Who {
     need_runlevel: bool,
     need_users: bool,
     my_line_only: bool,
-    has_records: bool,
     args: Vec<String>,
 }
 
@@ -321,8 +319,7 @@ impl Who {
             println!("{}", users.join(" "));
             println!("# users={}", users.len());
         } else {
-            let mut records = Utmpx::iter_all_records().read_from(f).peekable();
-            self.has_records = records.peek().is_some();
+            let records = Utmpx::iter_all_records().read_from(f).peekable();
 
             if self.include_heading {
                 self.print_heading()
diff --git a/src/uucore/src/lib/features/perms.rs b/src/uucore/src/lib/features/perms.rs
index 66db15451..36f56206d 100644
--- a/src/uucore/src/lib/features/perms.rs
+++ b/src/uucore/src/lib/features/perms.rs
@@ -31,9 +31,9 @@ fn chgrp<P: AsRef<Path>>(path: P, dgid: gid_t, follow: bool) -> IOResult<()> {
     let s = CString::new(path.as_os_str().as_bytes()).unwrap();
     let ret = unsafe {
         if follow {
-            libc::chown(s.as_ptr(), (0 as gid_t).wrapping_sub(1), dgid)
+            libc::chown(s.as_ptr(), 0_u32.wrapping_sub(1), dgid)
         } else {
-            lchown(s.as_ptr(), (0 as gid_t).wrapping_sub(1), dgid)
+            lchown(s.as_ptr(), 0_u32.wrapping_sub(1), dgid)
         }
     };
     if ret == 0 {