diff --git a/Cargo.lock b/Cargo.lock
index d767526ab..6c30a182d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -669,9 +669,9 @@ checksum = "0e25ea47919b1560c4e3b7fe0aaab9becf5b84a10325ddf7db0f0ba5e1026499"
 
 [[package]]
 name = "digest"
-version = "0.6.2"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5b29bf156f3f4b3c4f610a25ff69370616ae6e0657d416de22645483e72af0a"
+checksum = "ecae1c064e29fcabb6c2e9939e53dc7da72ed90234ae36ebfe03a478742efbd1"
 dependencies = [
  "generic-array",
 ]
@@ -2608,6 +2608,7 @@ dependencies = [
  "lscolors",
  "number_prefix",
  "once_cell",
+ "selinux",
  "term_grid",
  "termsize",
  "unicode-width",
diff --git a/Cargo.toml b/Cargo.toml
index 7b1399abf..701dd8b4a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -148,7 +148,7 @@ feat_os_unix_musl = [
 # NOTE:
 # The selinux(-sys) crate requires `libselinux` headers and shared library to be accessible in the C toolchain at compile time.
 # Running a uutils compiled with `feat_selinux` requires an SELinux enabled Kernel at run time.
-feat_selinux = ["cp/selinux", "id/selinux", "selinux", "feat_require_selinux"]
+feat_selinux = ["cp/selinux", "id/selinux", "ls/selinux", "selinux", "feat_require_selinux"]
 # "feat_acl" == set of utilities providing support for acl (access control lists) if enabled with `--features feat_acl`.
 # NOTE:
 # On linux, the posix-acl/acl-sys crate requires `libacl` headers and shared library to be accessible in the C toolchain at compile time.
diff --git a/src/uu/arch/src/arch.rs b/src/uu/arch/src/arch.rs
index 478fef6f1..d23a11cc8 100644
--- a/src/uu/arch/src/arch.rs
+++ b/src/uu/arch/src/arch.rs
@@ -6,9 +6,6 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use platform_info::*;
 
 use clap::{crate_version, App};
diff --git a/src/uu/base32/src/base32.rs b/src/uu/base32/src/base32.rs
index 667fd927e..f4b4b49de 100644
--- a/src/uu/base32/src/base32.rs
+++ b/src/uu/base32/src/base32.rs
@@ -5,13 +5,10 @@
 // For the full copyright and license information, please view the LICENSE file
 // that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use std::io::{stdin, Read};
 
 use clap::App;
-use uucore::encoding::Format;
+use uucore::{encoding::Format, error::UResult};
 
 pub mod base_common;
 
@@ -24,27 +21,22 @@ static ABOUT: &str = "
  to attempt to recover from any other non-alphabet bytes in the
  encoded stream.
 ";
-static VERSION: &str = env!("CARGO_PKG_VERSION");
-
-static BASE_CMD_PARSE_ERROR: i32 = 1;
 
 fn usage() -> String {
     format!("{0} [OPTION]... [FILE]", uucore::execution_phrase())
 }
 
-pub fn uumain(args: impl uucore::Args) -> i32 {
+#[uucore_procs::gen_uumain]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let format = Format::Base32;
     let usage = usage();
-    let name = uucore::util_name();
 
-    let config_result: Result<base_common::Config, String> =
-        base_common::parse_base_cmd_args(args, name, VERSION, ABOUT, &usage);
-    let config = config_result.unwrap_or_else(|s| crash!(BASE_CMD_PARSE_ERROR, "{}", s));
+    let config: base_common::Config = base_common::parse_base_cmd_args(args, ABOUT, &usage)?;
 
     // Create a reference to stdin so we can return a locked stdin from
     // parse_base_cmd_args
     let stdin_raw = stdin();
-    let mut input: Box<dyn Read> = base_common::get_input(&config, &stdin_raw);
+    let mut input: Box<dyn Read> = base_common::get_input(&config, &stdin_raw)?;
 
     base_common::handle_input(
         &mut input,
@@ -52,12 +44,9 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         config.wrap_cols,
         config.ignore_garbage,
         config.decode,
-        name,
-    );
-
-    0
+    )
 }
 
 pub fn uu_app() -> App<'static, 'static> {
-    base_common::base_app(uucore::util_name(), VERSION, ABOUT)
+    base_common::base_app(ABOUT)
 }
diff --git a/src/uu/base32/src/base_common.rs b/src/uu/base32/src/base_common.rs
index 0fd0fa5c4..015925e12 100644
--- a/src/uu/base32/src/base_common.rs
+++ b/src/uu/base32/src/base_common.rs
@@ -11,13 +11,16 @@ use std::io::{stdout, Read, Write};
 
 use uucore::display::Quotable;
 use uucore::encoding::{wrap_print, Data, Format};
+use uucore::error::{FromIo, UResult, USimpleError, UUsageError};
 use uucore::InvalidEncodingHandling;
 
 use std::fs::File;
 use std::io::{BufReader, Stdin};
 use std::path::Path;
 
-use clap::{App, Arg};
+use clap::{crate_version, App, Arg};
+
+pub static BASE_CMD_PARSE_ERROR: i32 = 1;
 
 // Config.
 pub struct Config {
@@ -35,15 +38,14 @@ pub mod options {
 }
 
 impl Config {
-    pub fn from(app_name: &str, options: &clap::ArgMatches) -> Result<Config, String> {
+    pub fn from(options: &clap::ArgMatches) -> UResult<Config> {
         let file: Option<String> = match options.values_of(options::FILE) {
             Some(mut values) => {
                 let name = values.next().unwrap();
                 if let Some(extra_op) = values.next() {
-                    return Err(format!(
-                        "extra operand {}\nTry '{} --help' for more information.",
-                        extra_op.quote(),
-                        app_name
+                    return Err(UUsageError::new(
+                        BASE_CMD_PARSE_ERROR,
+                        format!("extra operand {}", extra_op.quote(),),
                     ));
                 }
 
@@ -51,7 +53,10 @@ impl Config {
                     None
                 } else {
                     if !Path::exists(Path::new(name)) {
-                        return Err(format!("{}: No such file or directory", name.maybe_quote()));
+                        return Err(USimpleError::new(
+                            BASE_CMD_PARSE_ERROR,
+                            format!("{}: No such file or directory", name.maybe_quote()),
+                        ));
                     }
                     Some(name.to_owned())
                 }
@@ -62,8 +67,12 @@ impl Config {
         let cols = options
             .value_of(options::WRAP)
             .map(|num| {
-                num.parse::<usize>()
-                    .map_err(|_| format!("invalid wrap size: {}", num.quote()))
+                num.parse::<usize>().map_err(|_| {
+                    USimpleError::new(
+                        BASE_CMD_PARSE_ERROR,
+                        format!("invalid wrap size: {}", num.quote()),
+                    )
+                })
             })
             .transpose()?;
 
@@ -76,23 +85,17 @@ impl Config {
     }
 }
 
-pub fn parse_base_cmd_args(
-    args: impl uucore::Args,
-    name: &str,
-    version: &str,
-    about: &str,
-    usage: &str,
-) -> Result<Config, String> {
-    let app = base_app(name, version, about).usage(usage);
+pub fn parse_base_cmd_args(args: impl uucore::Args, about: &str, usage: &str) -> UResult<Config> {
+    let app = base_app(about).usage(usage);
     let arg_list = args
         .collect_str(InvalidEncodingHandling::ConvertLossy)
         .accept_any();
-    Config::from(name, &app.get_matches_from(arg_list))
+    Config::from(&app.get_matches_from(arg_list))
 }
 
-pub fn base_app<'a>(name: &str, version: &'a str, about: &'a str) -> App<'static, 'a> {
-    App::new(name)
-        .version(version)
+pub fn base_app<'a>(about: &'a str) -> App<'static, 'a> {
+    App::new(uucore::util_name())
+        .version(crate_version!())
         .about(about)
         // Format arguments.
         .arg(
@@ -121,14 +124,15 @@ pub fn base_app<'a>(name: &str, version: &'a str, about: &'a str) -> App<'static
         .arg(Arg::with_name(options::FILE).index(1).multiple(true))
 }
 
-pub fn get_input<'a>(config: &Config, stdin_ref: &'a Stdin) -> Box<dyn Read + 'a> {
+pub fn get_input<'a>(config: &Config, stdin_ref: &'a Stdin) -> UResult<Box<dyn Read + 'a>> {
     match &config.to_read {
         Some(name) => {
-            let file_buf = crash_if_err!(1, File::open(Path::new(name)));
-            Box::new(BufReader::new(file_buf)) // as Box<dyn Read>
+            let file_buf =
+                File::open(Path::new(name)).map_err_context(|| name.maybe_quote().to_string())?;
+            Ok(Box::new(BufReader::new(file_buf))) // as Box<dyn Read>
         }
         None => {
-            Box::new(stdin_ref.lock()) // as Box<dyn Read>
+            Ok(Box::new(stdin_ref.lock())) // as Box<dyn Read>
         }
     }
 }
@@ -139,8 +143,7 @@ pub fn handle_input<R: Read>(
     line_wrap: Option<usize>,
     ignore_garbage: bool,
     decode: bool,
-    name: &str,
-) {
+) -> UResult<()> {
     let mut data = Data::new(input, format).ignore_garbage(ignore_garbage);
     if let Some(wrap) = line_wrap {
         data = data.line_wrap(wrap);
@@ -150,28 +153,23 @@ pub fn handle_input<R: Read>(
         match data.encode() {
             Ok(s) => {
                 wrap_print(&data, s);
+                Ok(())
             }
-            Err(_) => {
-                eprintln!(
-                    "{}: error: invalid input (length must be multiple of 4 characters)",
-                    name
-                );
-                exit!(1)
-            }
+            Err(_) => Err(USimpleError::new(
+                1,
+                "error: invalid input (length must be multiple of 4 characters)",
+            )),
         }
     } else {
         match data.decode() {
             Ok(s) => {
                 if stdout().write_all(&s).is_err() {
                     // on windows console, writing invalid utf8 returns an error
-                    eprintln!("{}: error: Cannot write non-utf8 data", name);
-                    exit!(1)
+                    return Err(USimpleError::new(1, "error: cannot write non-utf8 data"));
                 }
+                Ok(())
             }
-            Err(_) => {
-                eprintln!("{}: error: invalid input", name);
-                exit!(1)
-            }
+            Err(_) => Err(USimpleError::new(1, "error: invalid input")),
         }
     }
 }
diff --git a/src/uu/base64/src/base64.rs b/src/uu/base64/src/base64.rs
index ded157362..c041d6d69 100644
--- a/src/uu/base64/src/base64.rs
+++ b/src/uu/base64/src/base64.rs
@@ -6,13 +6,10 @@
 // For the full copyright and license information, please view the LICENSE file
 // that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use uu_base32::base_common;
 pub use uu_base32::uu_app;
 
-use uucore::encoding::Format;
+use uucore::{encoding::Format, error::UResult};
 
 use std::io::{stdin, Read};
 
@@ -25,26 +22,22 @@ static ABOUT: &str = "
  to attempt to recover from any other non-alphabet bytes in the
  encoded stream.
 ";
-static VERSION: &str = env!("CARGO_PKG_VERSION");
-
-static BASE_CMD_PARSE_ERROR: i32 = 1;
 
 fn usage() -> String {
     format!("{0} [OPTION]... [FILE]", uucore::execution_phrase())
 }
 
-pub fn uumain(args: impl uucore::Args) -> i32 {
+#[uucore_procs::gen_uumain]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let format = Format::Base64;
     let usage = usage();
-    let name = uucore::util_name();
-    let config_result: Result<base_common::Config, String> =
-        base_common::parse_base_cmd_args(args, name, VERSION, ABOUT, &usage);
-    let config = config_result.unwrap_or_else(|s| crash!(BASE_CMD_PARSE_ERROR, "{}", s));
+
+    let config: base_common::Config = base_common::parse_base_cmd_args(args, ABOUT, &usage)?;
 
     // Create a reference to stdin so we can return a locked stdin from
     // parse_base_cmd_args
     let stdin_raw = stdin();
-    let mut input: Box<dyn Read> = base_common::get_input(&config, &stdin_raw);
+    let mut input: Box<dyn Read> = base_common::get_input(&config, &stdin_raw)?;
 
     base_common::handle_input(
         &mut input,
@@ -52,8 +45,5 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         config.wrap_cols,
         config.ignore_garbage,
         config.decode,
-        name,
-    );
-
-    0
+    )
 }
diff --git a/src/uu/basenc/src/basenc.rs b/src/uu/basenc/src/basenc.rs
index 86c251ad1..e4b24c351 100644
--- a/src/uu/basenc/src/basenc.rs
+++ b/src/uu/basenc/src/basenc.rs
@@ -8,13 +8,14 @@
 
 //spell-checker:ignore (args) lsbf msbf
 
-#[macro_use]
-extern crate uucore;
+use clap::{App, Arg};
+use uu_base32::base_common::{self, Config, BASE_CMD_PARSE_ERROR};
 
-use clap::{crate_version, App, Arg};
-use uu_base32::base_common::{self, Config};
-
-use uucore::{encoding::Format, InvalidEncodingHandling};
+use uucore::{
+    encoding::Format,
+    error::{UResult, UUsageError},
+    InvalidEncodingHandling,
+};
 
 use std::io::{stdin, Read};
 
@@ -26,8 +27,6 @@ static ABOUT: &str = "
  from any other non-alphabet bytes in the encoded stream.
 ";
 
-static BASE_CMD_PARSE_ERROR: i32 = 1;
-
 const ENCODINGS: &[(&str, Format)] = &[
     ("base64", Format::Base64),
     ("base64url", Format::Base64Url),
@@ -47,14 +46,14 @@ fn usage() -> String {
 }
 
 pub fn uu_app() -> App<'static, 'static> {
-    let mut app = base_common::base_app(uucore::util_name(), crate_version!(), ABOUT);
+    let mut app = base_common::base_app(ABOUT);
     for encoding in ENCODINGS {
         app = app.arg(Arg::with_name(encoding.0).long(encoding.0));
     }
     app
 }
 
-fn parse_cmd_args(args: impl uucore::Args) -> (Config, Format) {
+fn parse_cmd_args(args: impl uucore::Args) -> UResult<(Config, Format)> {
     let usage = usage();
     let matches = uu_app().usage(&usage[..]).get_matches_from(
         args.collect_str(InvalidEncodingHandling::ConvertLossy)
@@ -63,24 +62,19 @@ fn parse_cmd_args(args: impl uucore::Args) -> (Config, Format) {
     let format = ENCODINGS
         .iter()
         .find(|encoding| matches.is_present(encoding.0))
-        .unwrap_or_else(|| {
-            show_usage_error!("missing encoding type");
-            std::process::exit(1)
-        })
+        .ok_or_else(|| UUsageError::new(BASE_CMD_PARSE_ERROR, "missing encoding type"))?
         .1;
-    (
-        Config::from("basenc", &matches).unwrap_or_else(|s| crash!(BASE_CMD_PARSE_ERROR, "{}", s)),
-        format,
-    )
+    let config = Config::from(&matches)?;
+    Ok((config, format))
 }
 
-pub fn uumain(args: impl uucore::Args) -> i32 {
-    let name = uucore::util_name();
-    let (config, format) = parse_cmd_args(args);
+#[uucore_procs::gen_uumain]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
+    let (config, format) = parse_cmd_args(args)?;
     // Create a reference to stdin so we can return a locked stdin from
     // parse_base_cmd_args
     let stdin_raw = stdin();
-    let mut input: Box<dyn Read> = base_common::get_input(&config, &stdin_raw);
+    let mut input: Box<dyn Read> = base_common::get_input(&config, &stdin_raw)?;
 
     base_common::handle_input(
         &mut input,
@@ -88,8 +82,5 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         config.wrap_cols,
         config.ignore_garbage,
         config.decode,
-        name,
-    );
-
-    0
+    )
 }
diff --git a/src/uu/cat/src/cat.rs b/src/uu/cat/src/cat.rs
index baf8af6d5..308e11bfe 100644
--- a/src/uu/cat/src/cat.rs
+++ b/src/uu/cat/src/cat.rs
@@ -12,8 +12,6 @@
 
 #[cfg(unix)]
 extern crate unix_socket;
-#[macro_use]
-extern crate uucore;
 
 // last synced with: cat (GNU coreutils) 8.13
 use clap::{crate_version, App, Arg};
diff --git a/src/uu/chgrp/src/chgrp.rs b/src/uu/chgrp/src/chgrp.rs
index 1795ad0d5..c70e5e5c7 100644
--- a/src/uu/chgrp/src/chgrp.rs
+++ b/src/uu/chgrp/src/chgrp.rs
@@ -7,8 +7,6 @@
 
 // spell-checker:ignore (ToDO) COMFOLLOW Chowner RFILE RFILE's derefer dgid nonblank nonprint nonprinting
 
-#[macro_use]
-extern crate uucore;
 use uucore::display::Quotable;
 pub use uucore::entries;
 use uucore::error::{FromIo, UResult, USimpleError};
diff --git a/src/uu/chown/src/chown.rs b/src/uu/chown/src/chown.rs
index 1cd71d3f5..f24c4ec89 100644
--- a/src/uu/chown/src/chown.rs
+++ b/src/uu/chown/src/chown.rs
@@ -7,8 +7,6 @@
 
 // spell-checker:ignore (ToDO) COMFOLLOW Passwd RFILE RFILE's derefer dgid duid groupname
 
-#[macro_use]
-extern crate uucore;
 use uucore::display::Quotable;
 pub use uucore::entries::{self, Group, Locate, Passwd};
 use uucore::perms::{chown_base, options, IfFrom};
diff --git a/src/uu/cp/src/cp.rs b/src/uu/cp/src/cp.rs
index cd33f9fa6..518a2262c 100644
--- a/src/uu/cp/src/cp.rs
+++ b/src/uu/cp/src/cp.rs
@@ -49,6 +49,7 @@ use std::path::{Path, PathBuf, StripPrefixError};
 use std::str::FromStr;
 use std::string::ToString;
 use uucore::backup_control::{self, BackupMode};
+use uucore::error::{set_exit_code, ExitCode, UError, UResult};
 use uucore::fs::{canonicalize, MissingHandling, ResolveMode};
 use walkdir::WalkDir;
 
@@ -105,6 +106,12 @@ quick_error! {
     }
 }
 
+impl UError for Error {
+    fn code(&self) -> i32 {
+        EXIT_ERR
+    }
+}
+
 /// Continue next iteration of loop if result of expression is error
 macro_rules! or_continue(
     ($expr:expr) => (match $expr {
@@ -220,7 +227,6 @@ pub struct Options {
 
 static ABOUT: &str = "Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.";
 static LONG_HELP: &str = "";
-static EXIT_OK: i32 = 0;
 static EXIT_ERR: i32 = 1;
 
 fn usage() -> String {
@@ -446,7 +452,8 @@ pub fn uu_app() -> App<'static, 'static> {
              .multiple(true))
 }
 
-pub fn uumain(args: impl uucore::Args) -> i32 {
+#[uucore_procs::gen_uumain]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let usage = usage();
     let matches = uu_app()
         .after_help(&*format!(
@@ -457,11 +464,11 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         .usage(&usage[..])
         .get_matches_from(args);
 
-    let options = crash_if_err!(EXIT_ERR, Options::from_matches(&matches));
+    let options = Options::from_matches(&matches)?;
 
     if options.overwrite == OverwriteMode::NoClobber && options.backup != BackupMode::NoBackup {
         show_usage_error!("options --backup and --no-clobber are mutually exclusive");
-        return 1;
+        return Err(ExitCode(EXIT_ERR).into());
     }
 
     let paths: Vec<String> = matches
@@ -469,7 +476,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         .map(|v| v.map(ToString::to_string).collect())
         .unwrap_or_default();
 
-    let (sources, target) = crash_if_err!(EXIT_ERR, parse_path_args(&paths, &options));
+    let (sources, target) = parse_path_args(&paths, &options)?;
 
     if let Err(error) = copy(&sources, &target, &options) {
         match error {
@@ -479,10 +486,10 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
             // Else we caught a fatal bubbled-up error, log it to stderr
             _ => show_error!("{}", error),
         };
-        return EXIT_ERR;
+        set_exit_code(EXIT_ERR);
     }
 
-    EXIT_OK
+    Ok(())
 }
 
 impl ClobberMode {
@@ -1124,7 +1131,7 @@ fn copy_attribute(source: &Path, dest: &Path, attribute: &Attribute) -> CopyResu
                 let xattrs = xattr::list(source)?;
                 for attr in xattrs {
                     if let Some(attr_value) = xattr::get(source, attr.clone())? {
-                        crash_if_err!(EXIT_ERR, xattr::set(dest, attr, &attr_value[..]));
+                        xattr::set(dest, attr, &attr_value[..])?;
                     }
                 }
             }
diff --git a/src/uu/csplit/src/csplit.rs b/src/uu/csplit/src/csplit.rs
index dbf65b71d..0d99154df 100644
--- a/src/uu/csplit/src/csplit.rs
+++ b/src/uu/csplit/src/csplit.rs
@@ -320,18 +320,19 @@ impl<'a> SplitWriter<'a> {
             let l = line?;
             match n.cmp(&(&ln + 1)) {
                 Ordering::Less => {
-                    if input_iter.add_line_to_buffer(ln, l).is_some() {
-                        panic!("the buffer is big enough to contain 1 line");
-                    }
+                    assert!(
+                        input_iter.add_line_to_buffer(ln, l).is_none(),
+                        "the buffer is big enough to contain 1 line"
+                    );
                     ret = Ok(());
                     break;
                 }
                 Ordering::Equal => {
-                    if !self.options.suppress_matched
-                        && input_iter.add_line_to_buffer(ln, l).is_some()
-                    {
-                        panic!("the buffer is big enough to contain 1 line");
-                    }
+                    assert!(
+                        self.options.suppress_matched
+                            || input_iter.add_line_to_buffer(ln, l).is_none(),
+                        "the buffer is big enough to contain 1 line"
+                    );
                     ret = Ok(());
                     break;
                 }
@@ -378,9 +379,10 @@ impl<'a> SplitWriter<'a> {
                     match (self.options.suppress_matched, offset) {
                         // no offset, add the line to the next split
                         (false, 0) => {
-                            if input_iter.add_line_to_buffer(ln, l).is_some() {
-                                panic!("the buffer is big enough to contain 1 line");
-                            }
+                            assert!(
+                                input_iter.add_line_to_buffer(ln, l).is_none(),
+                                "the buffer is big enough to contain 1 line"
+                            );
                         }
                         // a positive offset, some more lines need to be added to the current split
                         (false, _) => self.writeln(l)?,
@@ -425,9 +427,10 @@ impl<'a> SplitWriter<'a> {
                     if !self.options.suppress_matched {
                         // add 1 to the buffer size to make place for the matched line
                         input_iter.set_size_of_buffer(offset_usize + 1);
-                        if input_iter.add_line_to_buffer(ln, l).is_some() {
-                            panic!("should be big enough to hold every lines");
-                        }
+                        assert!(
+                            input_iter.add_line_to_buffer(ln, l).is_none(),
+                            "should be big enough to hold every lines"
+                        );
                     }
                     self.finish_split();
                     if input_iter.buffer_len() < offset_usize {
diff --git a/src/uu/dd/src/parseargs/unit_tests.rs b/src/uu/dd/src/parseargs/unit_tests.rs
index b898f1e5d..21900ee49 100644
--- a/src/uu/dd/src/parseargs/unit_tests.rs
+++ b/src/uu/dd/src/parseargs/unit_tests.rs
@@ -35,12 +35,11 @@ fn unimplemented_flags_should_error_non_linux() {
         }
     }
 
-    if !succeeded.is_empty() {
-        panic!(
-            "The following flags did not panic as expected: {:?}",
-            succeeded
-        );
-    }
+    assert!(
+        succeeded.is_empty(),
+        "The following flags did not panic as expected: {:?}",
+        succeeded
+    );
 }
 
 #[test]
@@ -64,12 +63,11 @@ fn unimplemented_flags_should_error() {
         }
     }
 
-    if !succeeded.is_empty() {
-        panic!(
-            "The following flags did not panic as expected: {:?}",
-            succeeded
-        );
-    }
+    assert!(
+        succeeded.is_empty(),
+        "The following flags did not panic as expected: {:?}",
+        succeeded
+    );
 }
 
 #[test]
diff --git a/src/uu/df/src/df.rs b/src/uu/df/src/df.rs
index 310d3c664..2f703542c 100644
--- a/src/uu/df/src/df.rs
+++ b/src/uu/df/src/df.rs
@@ -6,8 +6,6 @@
 // For the full copyright and license information, please view the LICENSE file
 // that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
 use uucore::error::UError;
 use uucore::error::UResult;
 #[cfg(unix)]
diff --git a/src/uu/dirname/src/dirname.rs b/src/uu/dirname/src/dirname.rs
index 601d93ac0..129c9369e 100644
--- a/src/uu/dirname/src/dirname.rs
+++ b/src/uu/dirname/src/dirname.rs
@@ -5,9 +5,6 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use clap::{crate_version, App, Arg};
 use std::path::Path;
 use uucore::display::print_verbatim;
diff --git a/src/uu/echo/src/echo.rs b/src/uu/echo/src/echo.rs
index 601fd8d48..a0e6c0d9c 100644
--- a/src/uu/echo/src/echo.rs
+++ b/src/uu/echo/src/echo.rs
@@ -6,9 +6,6 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use clap::{crate_version, App, Arg};
 use std::io::{self, Write};
 use std::iter::Peekable;
diff --git a/src/uu/expr/src/expr.rs b/src/uu/expr/src/expr.rs
index 2d82300ff..6e2a8701a 100644
--- a/src/uu/expr/src/expr.rs
+++ b/src/uu/expr/src/expr.rs
@@ -5,10 +5,8 @@
 //* For the full copyright and license information, please view the LICENSE
 //* file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use clap::{crate_version, App, Arg};
+use uucore::error::{UResult, USimpleError};
 use uucore::InvalidEncodingHandling;
 
 mod syntax_tree;
@@ -23,7 +21,8 @@ pub fn uu_app() -> App<'static, 'static> {
         .arg(Arg::with_name(HELP).long(HELP))
 }
 
-pub fn uumain(args: impl uucore::Args) -> i32 {
+#[uucore_procs::gen_uumain]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let args = args
         .collect_str(InvalidEncodingHandling::ConvertLossy)
         .accept_any();
@@ -32,13 +31,13 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
     // The following usage should work without escaping hyphens: `expr -15 = 1 +  2 \* \( 3 - -4 \)`
 
     if maybe_handle_help_or_version(&args) {
-        0
+        Ok(())
     } else {
         let token_strings = args[1..].to_vec();
 
         match process_expr(&token_strings) {
             Ok(expr_result) => print_expr_ok(&expr_result),
-            Err(expr_error) => print_expr_error(&expr_error),
+            Err(expr_error) => Err(USimpleError::new(2, &expr_error)),
         }
     }
 }
@@ -49,19 +48,15 @@ fn process_expr(token_strings: &[String]) -> Result<String, String> {
     evaluate_ast(maybe_ast)
 }
 
-fn print_expr_ok(expr_result: &str) -> i32 {
+fn print_expr_ok(expr_result: &str) -> UResult<()> {
     println!("{}", expr_result);
     if expr_result == "0" || expr_result.is_empty() {
-        1
+        Err(1.into())
     } else {
-        0
+        Ok(())
     }
 }
 
-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> {
     maybe_ast.and_then(|ast| ast.evaluate())
 }
diff --git a/src/uu/false/src/false.rs b/src/uu/false/src/false.rs
index 88ec1af06..783c7fa0d 100644
--- a/src/uu/false/src/false.rs
+++ b/src/uu/false/src/false.rs
@@ -5,9 +5,6 @@
 //  * For the full copyright and license information, please view the LICENSE
 //  * file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use clap::App;
 use uucore::error::UResult;
 
diff --git a/src/uu/hashsum/Cargo.toml b/src/uu/hashsum/Cargo.toml
index 9ea142c8b..7cb88dede 100644
--- a/src/uu/hashsum/Cargo.toml
+++ b/src/uu/hashsum/Cargo.toml
@@ -15,7 +15,7 @@ edition = "2018"
 path = "src/hashsum.rs"
 
 [dependencies]
-digest = "0.6.2"
+digest = "0.6.1"
 clap = { version = "2.33", features = ["wrap_help"] }
 hex = "0.2.0"
 libc = "0.2.42"
diff --git a/src/uu/hostid/src/hostid.rs b/src/uu/hostid/src/hostid.rs
index 4c9cafa35..309e15990 100644
--- a/src/uu/hostid/src/hostid.rs
+++ b/src/uu/hostid/src/hostid.rs
@@ -7,9 +7,6 @@
 
 // spell-checker:ignore (ToDO) gethostid
 
-#[macro_use]
-extern crate uucore;
-
 use clap::{crate_version, App};
 use libc::c_long;
 use uucore::error::UResult;
diff --git a/src/uu/hostname/src/hostname.rs b/src/uu/hostname/src/hostname.rs
index 2de6627e8..9c8504027 100644
--- a/src/uu/hostname/src/hostname.rs
+++ b/src/uu/hostname/src/hostname.rs
@@ -7,9 +7,6 @@
 
 // spell-checker:ignore (ToDO) MAKEWORD addrs hashset
 
-#[macro_use]
-extern crate uucore;
-
 use std::collections::hash_set::HashSet;
 use std::net::ToSocketAddrs;
 use std::str;
diff --git a/src/uu/kill/src/kill.rs b/src/uu/kill/src/kill.rs
index f269f7283..e9b7ee349 100644
--- a/src/uu/kill/src/kill.rs
+++ b/src/uu/kill/src/kill.rs
@@ -158,18 +158,13 @@ fn print_signal(signal_name_or_value: &str) -> UResult<()> {
 }
 
 fn print_signals() {
-    let mut pos = 0;
     for (idx, signal) in ALL_SIGNALS.iter().enumerate() {
-        pos += signal.len();
-        print!("{}", signal);
-        if idx > 0 && pos > 73 {
-            println!();
-            pos = 0;
-        } else {
-            pos += 1;
+        if idx > 0 {
             print!(" ");
         }
+        print!("{}", signal);
     }
+    println!();
 }
 
 fn list(arg: Option<String>) -> UResult<()> {
diff --git a/src/uu/ls/Cargo.toml b/src/uu/ls/Cargo.toml
index e907e8e02..629a7a2d8 100644
--- a/src/uu/ls/Cargo.toml
+++ b/src/uu/ls/Cargo.toml
@@ -27,6 +27,7 @@ uucore = { version = ">=0.0.8", package = "uucore", path = "../../uucore", featu
 uucore_procs = { version=">=0.0.6", package = "uucore_procs", path = "../../uucore_procs" }
 once_cell = "1.7.2"
 atty = "0.2"
+selinux = { version="0.2.1", optional = true }
 
 [target.'cfg(unix)'.dependencies]
 lazy_static = "1.4.0"
@@ -35,6 +36,9 @@ lazy_static = "1.4.0"
 name = "ls"
 path = "src/main.rs"
 
+[features]
+feat_selinux = ["selinux"]
+
 [package.metadata.cargo-udeps.ignore]
 # Necessary for "make all"
 normal = ["uucore_procs"]
diff --git a/src/uu/ls/src/ls.rs b/src/uu/ls/src/ls.rs
index c5c65334e..3fa3b4f8e 100644
--- a/src/uu/ls/src/ls.rs
+++ b/src/uu/ls/src/ls.rs
@@ -50,6 +50,11 @@ use unicode_width::UnicodeWidthStr;
 use uucore::libc::{S_IXGRP, S_IXOTH, S_IXUSR};
 use uucore::{fs::display_permissions, version_cmp::version_cmp};
 
+#[cfg(not(feature = "selinux"))]
+static CONTEXT_HELP_TEXT: &str = "print any security context of each file (not enabled)";
+#[cfg(feature = "selinux")]
+static CONTEXT_HELP_TEXT: &str = "print any security context of each file";
+
 fn usage() -> String {
     format!("{0} [OPTION]... [FILE]...", uucore::execution_phrase())
 }
@@ -129,6 +134,7 @@ pub mod options {
     pub static FULL_TIME: &str = "full-time";
     pub static HIDE: &str = "hide";
     pub static IGNORE: &str = "ignore";
+    pub static CONTEXT: &str = "context";
 }
 
 const DEFAULT_TERM_WIDTH: u16 = 80;
@@ -239,6 +245,8 @@ struct Config {
     quoting_style: QuotingStyle,
     indicator_style: IndicatorStyle,
     time_style: TimeStyle,
+    context: bool,
+    selinux_supported: bool,
 }
 
 // Fields that can be removed or added to the long format
@@ -250,9 +258,18 @@ struct LongFormat {
     numeric_uid_gid: bool,
 }
 
+struct PaddingCollection {
+    longest_link_count_len: usize,
+    longest_uname_len: usize,
+    longest_group_len: usize,
+    longest_context_len: usize,
+    longest_size_len: usize,
+}
+
 impl Config {
     #[allow(clippy::cognitive_complexity)]
     fn from(options: &clap::ArgMatches) -> UResult<Config> {
+        let context = options.is_present(options::CONTEXT);
         let (mut format, opt) = if let Some(format_) = options.value_of(options::FORMAT) {
             (
                 match format_ {
@@ -596,6 +613,17 @@ impl Config {
             quoting_style,
             indicator_style,
             time_style,
+            context,
+            selinux_supported: {
+                #[cfg(feature = "selinux")]
+                {
+                    selinux::kernel_support() != selinux::KernelSupport::Unsupported
+                }
+                #[cfg(not(feature = "selinux"))]
+                {
+                    false
+                }
+            },
         })
     }
 }
@@ -1157,6 +1185,12 @@ only ignore '.' and '..'.",
                 .overrides_with(options::FULL_TIME)
                 .help("like -l --time-style=full-iso"),
         )
+        .arg(
+            Arg::with_name(options::CONTEXT)
+                .short("Z")
+                .long(options::CONTEXT)
+                .help(CONTEXT_HELP_TEXT),
+        )
         // Positional arguments
         .arg(
             Arg::with_name(options::PATHS)
@@ -1181,6 +1215,7 @@ struct PathData {
     // PathBuf that all above data corresponds to
     p_buf: PathBuf,
     must_dereference: bool,
+    security_context: String,
 }
 
 impl PathData {
@@ -1224,12 +1259,19 @@ impl PathData {
             None => OnceCell::new(),
         };
 
+        let security_context = if config.context {
+            get_security_context(config, &p_buf, must_dereference)
+        } else {
+            String::new()
+        };
+
         Self {
             md: OnceCell::new(),
             ft,
             display_name,
             p_buf,
             must_dereference,
+            security_context,
         }
     }
 
@@ -1398,7 +1440,7 @@ fn get_metadata(entry: &Path, dereference: bool) -> std::io::Result<Metadata> {
 }
 
 fn display_dir_entry_size(entry: &PathData, config: &Config) -> (usize, usize, usize, usize) {
-    // TODO: Cache/memoize the display_* results so we don't have to recalculate them.
+    // TODO: Cache/memorize the display_* results so we don't have to recalculate them.
     if let Some(md) = entry.md() {
         (
             display_symlink_count(md).len(),
@@ -1411,31 +1453,40 @@ fn display_dir_entry_size(entry: &PathData, config: &Config) -> (usize, usize, u
     }
 }
 
-fn pad_left(string: String, count: usize) -> String {
+fn pad_left(string: &str, count: usize) -> String {
     format!("{:>width$}", string, width = count)
 }
 
-fn pad_right(string: String, count: usize) -> String {
+fn pad_right(string: &str, count: usize) -> String {
     format!("{:<width$}", string, width = count)
 }
 
 fn display_items(items: &[PathData], config: &Config, out: &mut BufWriter<Stdout>) {
+    // `-Z`, `--context`:
+    // Display the SELinux security context or '?' if none is found. When used with the `-l`
+    // option, print the security context to the left of the size column.
+
     if config.format == Format::Long {
         let (
             mut longest_link_count_len,
             mut longest_uname_len,
             mut longest_group_len,
+            mut longest_context_len,
             mut longest_size_len,
-        ) = (1, 1, 1, 1);
+        ) = (1, 1, 1, 1, 1);
         let mut total_size = 0;
 
         for item in items {
+            let context_len = item.security_context.len();
             let (link_count_len, uname_len, group_len, size_len) =
                 display_dir_entry_size(item, config);
             longest_link_count_len = link_count_len.max(longest_link_count_len);
             longest_size_len = size_len.max(longest_size_len);
             longest_uname_len = uname_len.max(longest_uname_len);
             longest_group_len = group_len.max(longest_group_len);
+            if config.context {
+                longest_context_len = context_len.max(longest_context_len);
+            }
             longest_size_len = size_len.max(longest_size_len);
             total_size += item.md().map_or(0, |md| get_block_size(md, config));
         }
@@ -1447,16 +1498,31 @@ fn display_items(items: &[PathData], config: &Config, out: &mut BufWriter<Stdout
         for item in items {
             display_item_long(
                 item,
-                longest_link_count_len,
-                longest_uname_len,
-                longest_group_len,
-                longest_size_len,
+                PaddingCollection {
+                    longest_link_count_len,
+                    longest_uname_len,
+                    longest_group_len,
+                    longest_context_len,
+                    longest_size_len,
+                },
                 config,
                 out,
             );
         }
     } else {
-        let names = items.iter().filter_map(|i| display_file_name(i, config));
+        let mut longest_context_len = 1;
+        let prefix_context = if config.context {
+            for item in items {
+                let context_len = item.security_context.len();
+                longest_context_len = context_len.max(longest_context_len);
+            }
+            Some(longest_context_len)
+        } else {
+            None
+        };
+        let names = items
+            .iter()
+            .filter_map(|i| display_file_name(i, config, prefix_context));
 
         match config.format {
             Format::Columns => display_grid(names, config.width, Direction::TopToBottom, out),
@@ -1581,15 +1647,13 @@ fn display_grid(
 ///    longest_link_count_len: usize,
 ///    longest_uname_len: usize,
 ///    longest_group_len: usize,
+///    longest_context_len: usize,
 ///    longest_size_len: usize,
 /// ```
 /// that decide the maximum possible character count of each field.
 fn display_item_long(
     item: &PathData,
-    longest_link_count_len: usize,
-    longest_uname_len: usize,
-    longest_group_len: usize,
-    longest_size_len: usize,
+    padding: PaddingCollection,
     config: &Config,
     out: &mut BufWriter<Stdout>,
 ) {
@@ -1610,16 +1674,23 @@ fn display_item_long(
 
     let _ = write!(
         out,
-        "{} {}",
+        "{}{} {}",
         display_permissions(md, true),
-        pad_left(display_symlink_count(md), longest_link_count_len),
+        if item.security_context.len() > 1 {
+            // GNU `ls` uses a "." character to indicate a file with a security context,
+            // but not other alternate access method.
+            "."
+        } else {
+            ""
+        },
+        pad_left(&display_symlink_count(md), padding.longest_link_count_len),
     );
 
     if config.long.owner {
         let _ = write!(
             out,
             " {}",
-            pad_right(display_uname(md, config), longest_uname_len)
+            pad_right(&display_uname(md, config), padding.longest_uname_len)
         );
     }
 
@@ -1627,7 +1698,15 @@ fn display_item_long(
         let _ = write!(
             out,
             " {}",
-            pad_right(display_group(md, config), longest_group_len)
+            pad_right(&display_group(md, config), padding.longest_group_len)
+        );
+    }
+
+    if config.context {
+        let _ = write!(
+            out,
+            " {}",
+            pad_right(&item.security_context, padding.longest_context_len)
         );
     }
 
@@ -1637,19 +1716,19 @@ fn display_item_long(
         let _ = write!(
             out,
             " {}",
-            pad_right(display_uname(md, config), longest_uname_len)
+            pad_right(&display_uname(md, config), padding.longest_uname_len)
         );
     }
 
     let _ = writeln!(
         out,
         " {} {} {}",
-        pad_left(display_size_or_rdev(md, config), longest_size_len),
+        pad_left(&display_size_or_rdev(md, config), padding.longest_size_len),
         display_date(md, config),
         // unwrap is fine because it fails when metadata is not available
         // but we already know that it is because it's checked at the
         // start of the function.
-        display_file_name(item, config).unwrap().contents,
+        display_file_name(item, config, None).unwrap().contents,
     );
 }
 
@@ -1873,21 +1952,22 @@ fn classify_file(path: &PathData) -> Option<char> {
 /// * `config.indicator_style` to append specific characters to `name` using [`classify_file`].
 /// * `config.format` to display symlink targets if `Format::Long`. This function is also
 ///   responsible for coloring symlink target names if `config.color` is specified.
+/// * `config.context` to prepend security context to `name` if compiled with `feat_selinux`.
 ///
 /// Note that non-unicode sequences in symlink targets are dealt with using
 /// [`std::path::Path::to_string_lossy`].
-fn display_file_name(path: &PathData, config: &Config) -> Option<Cell> {
+fn display_file_name(
+    path: &PathData,
+    config: &Config,
+    prefix_context: Option<usize>,
+) -> Option<Cell> {
     // This is our return value. We start by `&path.display_name` and modify it along the way.
     let mut name = escape_name(&path.display_name, &config.quoting_style);
 
     #[cfg(unix)]
     {
         if config.format != Format::Long && config.inode {
-            name = path
-                .md()
-                .map_or_else(|| "?".to_string(), |md| get_inode(md))
-                + " "
-                + &name;
+            name = path.md().map_or_else(|| "?".to_string(), get_inode) + " " + &name;
         }
     }
 
@@ -1968,6 +2048,20 @@ fn display_file_name(path: &PathData, config: &Config) -> Option<Cell> {
         }
     }
 
+    // Prepend the security context to the `name` and adjust `width` in order
+    // to get correct alignment from later calls to`display_grid()`.
+    if config.context {
+        if let Some(pad_count) = prefix_context {
+            let security_context = if !matches!(config.format, Format::Commas) {
+                pad_left(&path.security_context, pad_count)
+            } else {
+                path.security_context.to_owned()
+            };
+            name = format!("{} {}", security_context, name);
+            width += security_context.len() + 1;
+        }
+    }
+
     Some(Cell {
         contents: name,
         width,
@@ -1992,3 +2086,44 @@ fn display_symlink_count(_metadata: &Metadata) -> String {
 fn display_symlink_count(metadata: &Metadata) -> String {
     metadata.nlink().to_string()
 }
+
+// This returns the SELinux security context as UTF8 `String`.
+// In the long term this should be changed to `OsStr`, see discussions at #2621/#2656
+#[allow(unused_variables)]
+fn get_security_context(config: &Config, p_buf: &Path, must_dereference: bool) -> String {
+    let substitute_string = "?".to_string();
+    if config.selinux_supported {
+        #[cfg(feature = "selinux")]
+        {
+            match selinux::SecurityContext::of_path(p_buf, must_dereference, false) {
+                Err(_r) => {
+                    // TODO: show the actual reason why it failed
+                    show_warning!("failed to get security context of: {}", p_buf.quote());
+                    substitute_string
+                }
+                Ok(None) => substitute_string,
+                Ok(Some(context)) => {
+                    let mut context = context.as_bytes();
+                    if context.ends_with(&[0]) {
+                        // TODO: replace with `strip_prefix()` when MSRV >= 1.51
+                        context = &context[..context.len() - 1]
+                    };
+                    String::from_utf8(context.to_vec()).unwrap_or_else(|e| {
+                        show_warning!(
+                            "getting security context of: {}: {}",
+                            p_buf.quote(),
+                            e.to_string()
+                        );
+                        String::from_utf8_lossy(context).into_owned()
+                    })
+                }
+            }
+        }
+        #[cfg(not(feature = "selinux"))]
+        {
+            substitute_string
+        }
+    } else {
+        substitute_string
+    }
+}
diff --git a/src/uu/mktemp/src/mktemp.rs b/src/uu/mktemp/src/mktemp.rs
index 81a3521e9..4318f0ad6 100644
--- a/src/uu/mktemp/src/mktemp.rs
+++ b/src/uu/mktemp/src/mktemp.rs
@@ -8,9 +8,6 @@
 
 // spell-checker:ignore (paths) GPGHome
 
-#[macro_use]
-extern crate uucore;
-
 use clap::{crate_version, App, Arg};
 use uucore::display::{println_verbatim, Quotable};
 use uucore::error::{FromIo, UError, UResult};
diff --git a/src/uu/more/src/more.rs b/src/uu/more/src/more.rs
index 3a601c1e8..d424d5a77 100644
--- a/src/uu/more/src/more.rs
+++ b/src/uu/more/src/more.rs
@@ -210,7 +210,7 @@ fn reset_term(stdout: &mut std::io::Stdout) {
 #[inline(always)]
 fn reset_term(_: &mut usize) {}
 
-fn more(buff: &str, mut stdout: &mut Stdout, next_file: Option<&str>, silent: bool) {
+fn more(buff: &str, stdout: &mut Stdout, next_file: Option<&str>, silent: bool) {
     let (cols, rows) = terminal::size().unwrap();
     let lines = break_buff(buff, usize::from(cols));
 
@@ -232,7 +232,7 @@ fn more(buff: &str, mut stdout: &mut Stdout, next_file: Option<&str>, silent: bo
                     code: KeyCode::Char('c'),
                     modifiers: KeyModifiers::CONTROL,
                 }) => {
-                    reset_term(&mut stdout);
+                    reset_term(stdout);
                     std::process::exit(0);
                 }
                 Event::Key(KeyEvent {
diff --git a/src/uu/od/src/output_info.rs b/src/uu/od/src/output_info.rs
index 49c2a09a2..cf050475a 100644
--- a/src/uu/od/src/output_info.rs
+++ b/src/uu/od/src/output_info.rs
@@ -145,13 +145,12 @@ impl OutputInfo {
         byte_size_block: usize,
         print_width_block: usize,
     ) -> [usize; MAX_BYTES_PER_UNIT] {
-        if byte_size_block > MAX_BYTES_PER_UNIT {
-            panic!(
-                "{}-bits types are unsupported. Current max={}-bits.",
-                8 * byte_size_block,
-                8 * MAX_BYTES_PER_UNIT
-            );
-        }
+        assert!(
+            byte_size_block <= MAX_BYTES_PER_UNIT,
+            "{}-bits types are unsupported. Current max={}-bits.",
+            8 * byte_size_block,
+            8 * MAX_BYTES_PER_UNIT
+        );
         let mut spacing = [0; MAX_BYTES_PER_UNIT];
 
         let mut byte_size = sf.byte_size();
diff --git a/src/uu/pwd/src/pwd.rs b/src/uu/pwd/src/pwd.rs
index 1138dba8e..8beb65dbd 100644
--- a/src/uu/pwd/src/pwd.rs
+++ b/src/uu/pwd/src/pwd.rs
@@ -5,9 +5,6 @@
 //  * For the full copyright and license information, please view the LICENSE
 //  * file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use clap::{crate_version, App, Arg};
 use std::env;
 use std::io;
diff --git a/src/uu/seq/src/seq.rs b/src/uu/seq/src/seq.rs
index aac8f2280..a76a23c4e 100644
--- a/src/uu/seq/src/seq.rs
+++ b/src/uu/seq/src/seq.rs
@@ -88,30 +88,65 @@ impl FromStr for Number {
         if s.starts_with('+') {
             s = &s[1..];
         }
+        let is_neg = s.starts_with('-');
 
-        match s.parse::<BigInt>() {
-            Ok(n) => {
-                // If `s` is '-0', then `parse()` returns
-                // `BigInt::zero()`, but we need to return
-                // `Number::MinusZero` instead.
-                if n == BigInt::zero() && s.starts_with('-') {
-                    Ok(Number::MinusZero)
-                } else {
-                    Ok(Number::BigInt(n))
+        match s.to_lowercase().find("0x") {
+            Some(i) if i <= 1 => match &s.as_bytes()[i + 2] {
+                    b'-' | b'+' => Err(format!(
+                    "invalid hexadecimal argument: {}\nTry '{} --help' for more information.",
+                    s.quote(),
+                    uucore::execution_phrase(),
+                )),
+                    // TODO: hexadecimal floating point parsing (see #2660)
+                    b'.' => Err(format!(
+                    "NotImplemented: hexadecimal floating point numbers: {}\nTry '{} --help' for more information.",
+                    s.quote(),
+                    uucore::execution_phrase(),
+                )),
+                    _ => {
+                        let num = BigInt::from_str_radix(&s[i + 2..], 16)
+                            .map_err(|_| format!(
+                    "invalid hexadecimal argument: {}\nTry '{} --help' for more information.",
+                    s.quote(),
+                    uucore::execution_phrase(),
+                ))?;
+                        match (is_neg, num == BigInt::zero()) {
+                            (true, true) => Ok(Number::MinusZero),
+                            (true, false) => Ok(Number::BigInt(-num)),
+                            (false, _) => Ok(Number::BigInt(num)),
+                        }
+                    }
+                },
+            Some(_) => Err(format!(
+                "invalid hexadecimal argument: {}\nTry '{} --help' for more information.",
+                s.quote(),
+                uucore::execution_phrase(),
+            )),
+
+            None => match s.parse::<BigInt>() {
+                Ok(n) => {
+                    // If `s` is '-0', then `parse()` returns
+                    // `BigInt::zero()`, but we need to return
+                    // `Number::MinusZero` instead.
+                    if n == BigInt::zero() && is_neg {
+                        Ok(Number::MinusZero)
+                    } else {
+                        Ok(Number::BigInt(n))
+                    }
                 }
-            }
-            Err(_) => match s.parse::<f64>() {
-                Ok(value) if value.is_nan() => Err(format!(
+                Err(_) => match s.parse::<f64>() {
+                    Ok(value) if value.is_nan() => Err(format!(
                     "invalid 'not-a-number' argument: {}\nTry '{} --help' for more information.",
                     s.quote(),
                     uucore::execution_phrase(),
                 )),
-                Ok(value) => Ok(Number::F64(value)),
-                Err(_) => Err(format!(
+                    Ok(value) => Ok(Number::F64(value)),
+                    Err(_) => Err(format!(
                     "invalid floating point argument: {}\nTry '{} --help' for more information.",
                     s.quote(),
                     uucore::execution_phrase(),
                 )),
+                },
             },
         }
     }
diff --git a/src/uu/sleep/src/sleep.rs b/src/uu/sleep/src/sleep.rs
index a70a524c4..80e8cd852 100644
--- a/src/uu/sleep/src/sleep.rs
+++ b/src/uu/sleep/src/sleep.rs
@@ -5,9 +5,6 @@
 //  * For the full copyright and license information, please view the LICENSE
 //  * file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use std::thread;
 use std::time::Duration;
 
diff --git a/src/uu/sort/src/sort.rs b/src/uu/sort/src/sort.rs
index fe286aa6d..bd79a6811 100644
--- a/src/uu/sort/src/sort.rs
+++ b/src/uu/sort/src/sort.rs
@@ -825,7 +825,7 @@ impl FieldSelector {
     fn parse(key: &str, global_settings: &GlobalSettings) -> UResult<Self> {
         let mut from_to = key.split(',');
         let (from, from_options) = Self::split_key_options(from_to.next().unwrap());
-        let to = from_to.next().map(|to| Self::split_key_options(to));
+        let to = from_to.next().map(Self::split_key_options);
         let options_are_empty = from_options.is_empty() && matches!(to, None | Some((_, "")));
 
         if options_are_empty {
diff --git a/src/uu/true/src/true.rs b/src/uu/true/src/true.rs
index 6b4a87bf1..b5fbf7c9d 100644
--- a/src/uu/true/src/true.rs
+++ b/src/uu/true/src/true.rs
@@ -5,9 +5,6 @@
 //  * For the full copyright and license information, please view the LICENSE
 //  * file that was distributed with this source code.
 
-#[macro_use]
-extern crate uucore;
-
 use clap::App;
 use uucore::error::UResult;
 
diff --git a/src/uu/unlink/src/unlink.rs b/src/uu/unlink/src/unlink.rs
index 1b4e4c998..58bb5442c 100644
--- a/src/uu/unlink/src/unlink.rs
+++ b/src/uu/unlink/src/unlink.rs
@@ -7,9 +7,6 @@
 
 /* last synced with: unlink (GNU coreutils) 8.21 */
 
-#[macro_use]
-extern crate uucore;
-
 use std::fs::remove_file;
 use std::path::Path;
 
diff --git a/src/uu/uptime/src/uptime.rs b/src/uu/uptime/src/uptime.rs
index f649b96b6..eabcd1abf 100644
--- a/src/uu/uptime/src/uptime.rs
+++ b/src/uu/uptime/src/uptime.rs
@@ -11,8 +11,6 @@
 use chrono::{Local, TimeZone, Utc};
 use clap::{crate_version, App, Arg};
 
-#[macro_use]
-extern crate uucore;
 // import crate time from utmpx
 pub use uucore::libc;
 use uucore::libc::time_t;
diff --git a/src/uu/users/src/users.rs b/src/uu/users/src/users.rs
index d374df181..d0768d8d1 100644
--- a/src/uu/users/src/users.rs
+++ b/src/uu/users/src/users.rs
@@ -11,6 +11,7 @@
 use std::path::Path;
 
 use clap::{crate_version, App, Arg};
+use uucore::error::UResult;
 use uucore::utmpx::{self, Utmpx};
 
 static ABOUT: &str = "Print the user names of users currently logged in to the current host";
@@ -29,7 +30,8 @@ If FILE is not specified, use {}.  /var/log/wtmp as FILE is common.",
     )
 }
 
-pub fn uumain(args: impl uucore::Args) -> i32 {
+#[uucore_procs::gen_uumain]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
     let usage = usage();
     let after_help = get_long_usage();
 
@@ -59,7 +61,7 @@ pub fn uumain(args: impl uucore::Args) -> i32 {
         println!("{}", users.join(" "));
     }
 
-    0
+    Ok(())
 }
 
 pub fn uu_app() -> App<'static, 'static> {
diff --git a/src/uu/whoami/src/whoami.rs b/src/uu/whoami/src/whoami.rs
index 830b86e63..0820588ee 100644
--- a/src/uu/whoami/src/whoami.rs
+++ b/src/uu/whoami/src/whoami.rs
@@ -9,8 +9,6 @@
 
 #[macro_use]
 extern crate clap;
-#[macro_use]
-extern crate uucore;
 
 use clap::App;
 
diff --git a/src/uu/yes/src/yes.rs b/src/uu/yes/src/yes.rs
index 03ae4e415..bbedc0af1 100644
--- a/src/uu/yes/src/yes.rs
+++ b/src/uu/yes/src/yes.rs
@@ -12,8 +12,6 @@ use std::io::{self, Write};
 
 #[macro_use]
 extern crate clap;
-#[macro_use]
-extern crate uucore;
 
 use clap::{App, Arg};
 use uucore::error::{UResult, USimpleError};
diff --git a/src/uucore/src/lib/features.rs b/src/uucore/src/lib/features.rs
index 42d8ffbe7..546cbea87 100644
--- a/src/uucore/src/lib/features.rs
+++ b/src/uucore/src/lib/features.rs
@@ -10,7 +10,7 @@ pub mod fsext;
 pub mod ringbuffer;
 
 // * (platform-specific) feature-gated modules
-// ** non-windows
+// ** non-windows (i.e. Unix + Fuchsia)
 #[cfg(all(not(windows), feature = "mode"))]
 pub mod mode;
 
diff --git a/src/uucore/src/lib/features/fsext.rs b/src/uucore/src/lib/features/fsext.rs
index 7525d9e41..97c1da79c 100644
--- a/src/uucore/src/lib/features/fsext.rs
+++ b/src/uucore/src/lib/features/fsext.rs
@@ -26,16 +26,12 @@ const MAX_PATH: usize = 266;
 static EXIT_ERR: i32 = 1;
 
 #[cfg(windows)]
-use std::ffi::OsString;
+use std::ffi::OsStr;
 #[cfg(windows)]
 use std::os::windows::ffi::OsStrExt;
 #[cfg(windows)]
-use std::os::windows::ffi::OsStringExt;
-#[cfg(windows)]
 use winapi::shared::minwindef::DWORD;
 #[cfg(windows)]
-use winapi::um::errhandlingapi::GetLastError;
-#[cfg(windows)]
 use winapi::um::fileapi::GetDiskFreeSpaceW;
 #[cfg(windows)]
 use winapi::um::fileapi::{
@@ -47,11 +43,12 @@ use winapi::um::handleapi::INVALID_HANDLE_VALUE;
 #[cfg(windows)]
 use winapi::um::winbase::DRIVE_REMOTE;
 
+// Warning: the pointer has to be used *immediately* or the Vec
+// it points to will be dropped!
 #[cfg(windows)]
 macro_rules! String2LPWSTR {
     ($str: expr) => {
-        OsString::from($str.clone())
-            .as_os_str()
+        OsStr::new(&$str)
             .encode_wide()
             .chain(Some(0))
             .collect::<Vec<u16>>()
@@ -62,10 +59,8 @@ macro_rules! String2LPWSTR {
 #[cfg(windows)]
 #[allow(non_snake_case)]
 fn LPWSTR2String(buf: &[u16]) -> String {
-    let len = unsafe { libc::wcslen(buf.as_ptr()) };
-    OsString::from_wide(&buf[..len as usize])
-        .into_string()
-        .unwrap()
+    let len = buf.iter().position(|&n| n == 0).unwrap();
+    String::from_utf16(&buf[..len]).unwrap()
 }
 
 use self::time::Timespec;
@@ -77,7 +72,6 @@ use std::borrow::Cow;
 use std::convert::{AsRef, From};
 #[cfg(unix)]
 use std::ffi::CString;
-#[cfg(unix)]
 use std::io::Error as IOError;
 #[cfg(unix)]
 use std::mem;
@@ -157,16 +151,14 @@ impl MountInfo {
     fn set_missing_fields(&mut self) {
         #[cfg(unix)]
         {
+            use std::os::unix::fs::MetadataExt;
             // We want to keep the dev_id on Windows
             // but set dev_id
-            let path = CString::new(self.mount_dir.clone()).unwrap();
-            unsafe {
-                let mut stat = mem::zeroed();
-                if libc::stat(path.as_ptr(), &mut stat) == 0 {
-                    self.dev_id = (stat.st_dev as i32).to_string();
-                } else {
-                    self.dev_id = "".to_string();
-                }
+            if let Ok(stat) = std::fs::metadata(&self.mount_dir) {
+                // Why do we cast this to i32?
+                self.dev_id = (stat.dev() as i32).to_string()
+            } else {
+                self.dev_id = "".to_string();
             }
         }
         // set MountInfo::dummy
@@ -247,8 +239,7 @@ impl MountInfo {
         volume_name.pop();
         unsafe {
             QueryDosDeviceW(
-                OsString::from(volume_name.clone())
-                    .as_os_str()
+                OsStr::new(&volume_name)
                     .encode_wide()
                     .chain(Some(0))
                     .skip(4)
@@ -445,9 +436,11 @@ pub fn read_fs_list() -> Vec<MountInfo> {
             FindFirstVolumeW(volume_name_buf.as_mut_ptr(), volume_name_buf.len() as DWORD)
         };
         if INVALID_HANDLE_VALUE == find_handle {
-            crash!(EXIT_ERR, "FindFirstVolumeW failed: {}", unsafe {
-                GetLastError()
-            });
+            crash!(
+                EXIT_ERR,
+                "FindFirstVolumeW failed: {}",
+                IOError::last_os_error()
+            );
         }
         let mut mounts = Vec::<MountInfo>::new();
         loop {
@@ -466,8 +459,9 @@ pub fn read_fs_list() -> Vec<MountInfo> {
                     volume_name_buf.len() as DWORD,
                 )
             } {
-                let err = unsafe { GetLastError() };
-                if err != winapi::shared::winerror::ERROR_NO_MORE_FILES {
+                let err = IOError::last_os_error();
+                if err.raw_os_error() != Some(winapi::shared::winerror::ERROR_NO_MORE_FILES as i32)
+                {
                     crash!(EXIT_ERR, "FindNextVolumeW failed: {}", err);
                 }
                 break;
@@ -527,7 +521,7 @@ impl FsUsage {
             crash!(
                 EXIT_ERR,
                 "GetVolumePathNamesForVolumeNameW failed: {}",
-                unsafe { GetLastError() }
+                IOError::last_os_error()
             );
         }
 
@@ -547,9 +541,11 @@ impl FsUsage {
         };
         if 0 == success {
             // Fails in case of CD for example
-            //crash!(EXIT_ERR, "GetDiskFreeSpaceW failed: {}", unsafe {
-            //GetLastError()
-            //});
+            // crash!(
+            //     EXIT_ERR,
+            //     "GetDiskFreeSpaceW failed: {}",
+            //     IOError::last_os_error()
+            // );
         }
 
         let bytes_per_cluster = sectors_per_cluster as u64 * bytes_per_sector as u64;
diff --git a/src/uucore/src/lib/features/mode.rs b/src/uucore/src/lib/features/mode.rs
index 02e78ba9b..72083e799 100644
--- a/src/uucore/src/lib/features/mode.rs
+++ b/src/uucore/src/lib/features/mode.rs
@@ -143,6 +143,13 @@ pub fn parse_mode(mode: &str) -> Result<mode_t, String> {
 }
 
 pub fn get_umask() -> u32 {
+    // There's no portable way to read the umask without changing it.
+    // We have to replace it and then quickly set it back, hopefully before
+    // some other thread is affected.
+    // On modern Linux kernels the current umask could instead be read
+    // from /proc/self/status. But that's a lot of work.
+    // SAFETY: umask always succeeds and doesn't operate on memory. Races are
+    // possible but it can't violate Rust's guarantees.
     let mask = unsafe { umask(0) };
     unsafe { umask(mask) };
     mask as u32
diff --git a/src/uucore/src/lib/features/process.rs b/src/uucore/src/lib/features/process.rs
index fc4b7ed48..d0f530a5a 100644
--- a/src/uucore/src/lib/features/process.rs
+++ b/src/uucore/src/lib/features/process.rs
@@ -19,6 +19,8 @@ use std::process::ExitStatus as StdExitStatus;
 use std::thread;
 use std::time::{Duration, Instant};
 
+// SAFETY: These functions always succeed and return simple integers.
+
 /// `geteuid()` returns the effective user ID of the calling process.
 pub fn geteuid() -> uid_t {
     unsafe { libc::geteuid() }
@@ -96,6 +98,9 @@ impl fmt::Display for ExitStatus {
 /// Missing methods for Child objects
 pub trait ChildExt {
     /// Send a signal to a Child process.
+    ///
+    /// Caller beware: if the process already exited then you may accidentally
+    /// send the signal to an unrelated process that recycled the PID.
     fn send_signal(&mut self, signal: usize) -> io::Result<()>;
 
     /// Wait for a process to finish or return after the specified duration.
diff --git a/src/uucore/src/lib/lib.rs b/src/uucore/src/lib/lib.rs
index 79cc2afc3..3d2d867bd 100644
--- a/src/uucore/src/lib/lib.rs
+++ b/src/uucore/src/lib/lib.rs
@@ -41,7 +41,7 @@ pub use crate::features::fsext;
 pub use crate::features::ringbuffer;
 
 // * (platform-specific) feature-gated modules
-// ** non-windows
+// ** non-windows (i.e. Unix + Fuchsia)
 #[cfg(all(not(windows), feature = "mode"))]
 pub use crate::features::mode;
 // ** unix-only
diff --git a/src/uucore_procs/src/lib.rs b/src/uucore_procs/src/lib.rs
index 092a4a66c..13b1dae3b 100644
--- a/src/uucore_procs/src/lib.rs
+++ b/src/uucore_procs/src/lib.rs
@@ -101,7 +101,7 @@ pub fn gen_uumain(_args: TokenStream, stream: TokenStream) -> TokenStream {
                 Err(e) => {
                     let s = format!("{}", e);
                     if s != "" {
-                        show_error!("{}", s);
+                        uucore::show_error!("{}", s);
                     }
                     if e.usage() {
                         eprintln!("Try '{} --help' for more information.", uucore::execution_phrase());
diff --git a/tests/by-util/test_base32.rs b/tests/by-util/test_base32.rs
index 5c74c5b59..ffe2cf74c 100644
--- a/tests/by-util/test_base32.rs
+++ b/tests/by-util/test_base32.rs
@@ -113,12 +113,18 @@ fn test_wrap_bad_arg() {
 
 #[test]
 fn test_base32_extra_operand() {
+    let ts = TestScenario::new(util_name!());
+
     // Expect a failure when multiple files are specified.
-    new_ucmd!()
+    ts.ucmd()
         .arg("a.txt")
         .arg("b.txt")
         .fails()
-        .stderr_only("base32: extra operand 'b.txt'\nTry 'base32 --help' for more information.");
+        .stderr_only(format!(
+            "{0}: extra operand 'b.txt'\nTry '{1} {0} --help' for more information.",
+            ts.util_name,
+            ts.bin_path.to_string_lossy()
+        ));
 }
 
 #[test]
diff --git a/tests/by-util/test_base64.rs b/tests/by-util/test_base64.rs
index a860aae91..87aa0db44 100644
--- a/tests/by-util/test_base64.rs
+++ b/tests/by-util/test_base64.rs
@@ -95,12 +95,18 @@ fn test_wrap_bad_arg() {
 
 #[test]
 fn test_base64_extra_operand() {
+    let ts = TestScenario::new(util_name!());
+
     // Expect a failure when multiple files are specified.
-    new_ucmd!()
+    ts.ucmd()
         .arg("a.txt")
         .arg("b.txt")
         .fails()
-        .stderr_only("base64: extra operand 'b.txt'\nTry 'base64 --help' for more information.");
+        .stderr_only(format!(
+            "{0}: extra operand 'b.txt'\nTry '{1} {0} --help' for more information.",
+            ts.util_name,
+            ts.bin_path.to_string_lossy()
+        ));
 }
 
 #[test]
diff --git a/tests/by-util/test_kill.rs b/tests/by-util/test_kill.rs
index f5166c428..40b9cec67 100644
--- a/tests/by-util/test_kill.rs
+++ b/tests/by-util/test_kill.rs
@@ -56,6 +56,12 @@ fn test_kill_list_all_signals() {
         .stdout_contains("HUP");
 }
 
+#[test]
+fn test_kill_list_final_new_line() {
+    let re = Regex::new("\\n$").unwrap();
+    assert!(re.is_match(new_ucmd!().arg("-l").succeeds().stdout_str()));
+}
+
 #[test]
 fn test_kill_list_all_signals_as_table() {
     // Check for a few signals.  Do not try to be comprehensive.
diff --git a/tests/by-util/test_ls.rs b/tests/by-util/test_ls.rs
index 4082a5015..56711d6e0 100644
--- a/tests/by-util/test_ls.rs
+++ b/tests/by-util/test_ls.rs
@@ -347,6 +347,7 @@ fn test_ls_long_format() {
         // A line of the output should be:
         // One of the characters -bcCdDlMnpPsStTx?
         // rwx, with - for missing permissions, thrice.
+        // Zero or one "." for indicating a file with security context
         // A number, preceded by column whitespace, and followed by a single space.
         // A username, currently [^ ], followed by column whitespace, twice (or thrice for Hurd).
         // A number, followed by a single space.
@@ -356,13 +357,13 @@ fn test_ls_long_format() {
         // and followed by a single space.
         // Whatever comes after is irrelevant to this specific test.
         scene.ucmd().arg(arg).arg("test-long-dir").succeeds().stdout_matches(&Regex::new(
-            r"\n[-bcCdDlMnpPsStTx?]([r-][w-][xt-]){3} +\d+ [^ ]+ +[^ ]+( +[^ ]+)? +\d+ [A-Z][a-z]{2} {0,2}\d{0,2} {0,2}[0-9:]+ "
+            r"\n[-bcCdDlMnpPsStTx?]([r-][w-][xt-]){3}\.? +\d+ [^ ]+ +[^ ]+( +[^ ]+)? +\d+ [A-Z][a-z]{2} {0,2}\d{0,2} {0,2}[0-9:]+ "
         ).unwrap());
     }
 
     // This checks for the line with the .. entry. The uname and group should be digits.
     scene.ucmd().arg("-lan").arg("test-long-dir").succeeds().stdout_matches(&Regex::new(
-        r"\nd([r-][w-][xt-]){3} +\d+ \d+ +\d+( +\d+)? +\d+ [A-Z][a-z]{2} {0,2}\d{0,2} {0,2}[0-9:]+ \.\."
+        r"\nd([r-][w-][xt-]){3}\.? +\d+ \d+ +\d+( +\d+)? +\d+ [A-Z][a-z]{2} {0,2}\d{0,2} {0,2}[0-9:]+ \.\."
     ).unwrap());
 }
 
@@ -370,6 +371,7 @@ fn test_ls_long_format() {
 /// This test is mainly about coloring, but, the recursion, symlink `->` processing,
 /// and `.` and `..` being present in `-a` all need to work for the test to pass.
 /// This test does not really test anything provided by `-l` but the file names and symlinks.
+#[cfg(all(feature = "ln", feature = "mkdir", feature = "touch"))]
 #[test]
 #[cfg(all(feature = "ln", feature = "mkdir", feature = "touch"))]
 fn test_ls_long_symlink_color() {
@@ -636,55 +638,57 @@ fn test_ls_long_formats() {
     let at = &scene.fixtures;
     at.touch(&at.plus_as_string("test-long-formats"));
 
+    // Zero or one "." for indicating a file with security context
+
     // Regex for three names, so all of author, group and owner
-    let re_three = Regex::new(r"[xrw-]{9} \d ([-0-9_a-z]+ ){3}0").unwrap();
+    let re_three = Regex::new(r"[xrw-]{9}\.? \d ([-0-9_a-z]+ ){3}0").unwrap();
 
     #[cfg(unix)]
-    let re_three_num = Regex::new(r"[xrw-]{9} \d (\d+ ){3}0").unwrap();
+    let re_three_num = Regex::new(r"[xrw-]{9}\.? \d (\d+ ){3}0").unwrap();
 
     // Regex for two names, either:
     // - group and owner
     // - author and owner
     // - author and group
-    let re_two = Regex::new(r"[xrw-]{9} \d ([-0-9_a-z]+ ){2}0").unwrap();
+    let re_two = Regex::new(r"[xrw-]{9}\.? \d ([-0-9_a-z]+ ){2}0").unwrap();
 
     #[cfg(unix)]
-    let re_two_num = Regex::new(r"[xrw-]{9} \d (\d+ ){2}0").unwrap();
+    let re_two_num = Regex::new(r"[xrw-]{9}\.? \d (\d+ ){2}0").unwrap();
 
     // Regex for one name: author, group or owner
-    let re_one = Regex::new(r"[xrw-]{9} \d [-0-9_a-z]+ 0").unwrap();
+    let re_one = Regex::new(r"[xrw-]{9}\.? \d [-0-9_a-z]+ 0").unwrap();
 
     #[cfg(unix)]
-    let re_one_num = Regex::new(r"[xrw-]{9} \d \d+ 0").unwrap();
+    let re_one_num = Regex::new(r"[xrw-]{9}\.? \d \d+ 0").unwrap();
 
     // Regex for no names
-    let re_zero = Regex::new(r"[xrw-]{9} \d 0").unwrap();
+    let re_zero = Regex::new(r"[xrw-]{9}\.? \d 0").unwrap();
 
-    let result = scene
+    scene
         .ucmd()
         .arg("-l")
         .arg("--author")
         .arg("test-long-formats")
-        .succeeds();
-    assert!(re_three.is_match(result.stdout_str()));
+        .succeeds()
+        .stdout_matches(&re_three);
 
-    let result = scene
+    scene
         .ucmd()
         .arg("-l1")
         .arg("--author")
         .arg("test-long-formats")
-        .succeeds();
-    assert!(re_three.is_match(result.stdout_str()));
+        .succeeds()
+        .stdout_matches(&re_three);
 
     #[cfg(unix)]
     {
-        let result = scene
+        scene
             .ucmd()
             .arg("-n")
             .arg("--author")
             .arg("test-long-formats")
-            .succeeds();
-        assert!(re_three_num.is_match(result.stdout_str()));
+            .succeeds()
+            .stdout_matches(&re_three_num);
     }
 
     for arg in &[
@@ -694,22 +698,22 @@ fn test_ls_long_formats() {
         "-lG --author",           // only author and owner
         "-l --no-group --author", // only author and owner
     ] {
-        let result = scene
+        scene
             .ucmd()
             .args(&arg.split(' ').collect::<Vec<_>>())
             .arg("test-long-formats")
-            .succeeds();
-        assert!(re_two.is_match(result.stdout_str()));
+            .succeeds()
+            .stdout_matches(&re_two);
 
         #[cfg(unix)]
         {
-            let result = scene
+            scene
                 .ucmd()
                 .arg("-n")
                 .args(&arg.split(' ').collect::<Vec<_>>())
                 .arg("test-long-formats")
-                .succeeds();
-            assert!(re_two_num.is_match(result.stdout_str()));
+                .succeeds()
+                .stdout_matches(&re_two_num);
         }
     }
 
@@ -723,22 +727,22 @@ fn test_ls_long_formats() {
         "-l --no-group", // only owner
         "-gG --author",  // only author
     ] {
-        let result = scene
+        scene
             .ucmd()
             .args(&arg.split(' ').collect::<Vec<_>>())
             .arg("test-long-formats")
-            .succeeds();
-        assert!(re_one.is_match(result.stdout_str()));
+            .succeeds()
+            .stdout_matches(&re_one);
 
         #[cfg(unix)]
         {
-            let result = scene
+            scene
                 .ucmd()
                 .arg("-n")
                 .args(&arg.split(' ').collect::<Vec<_>>())
                 .arg("test-long-formats")
-                .succeeds();
-            assert!(re_one_num.is_match(result.stdout_str()));
+                .succeeds()
+                .stdout_matches(&re_one_num);
         }
     }
 
@@ -755,22 +759,22 @@ fn test_ls_long_formats() {
         "-og1",
         "-og1l",
     ] {
-        let result = scene
+        scene
             .ucmd()
             .args(&arg.split(' ').collect::<Vec<_>>())
             .arg("test-long-formats")
-            .succeeds();
-        assert!(re_zero.is_match(result.stdout_str()));
+            .succeeds()
+            .stdout_matches(&re_zero);
 
         #[cfg(unix)]
         {
-            let result = scene
+            scene
                 .ucmd()
                 .arg("-n")
                 .args(&arg.split(' ').collect::<Vec<_>>())
                 .arg("test-long-formats")
-                .succeeds();
-            assert!(re_zero.is_match(result.stdout_str()));
+                .succeeds()
+                .stdout_matches(&re_zero);
         }
     }
 }
@@ -1248,7 +1252,7 @@ fn test_ls_inode() {
     at.touch(file);
 
     let re_short = Regex::new(r" *(\d+) test_inode").unwrap();
-    let re_long = Regex::new(r" *(\d+) [xrw-]{10} \d .+ test_inode").unwrap();
+    let re_long = Regex::new(r" *(\d+) [xrw-]{10}\.? \d .+ test_inode").unwrap();
 
     let result = scene.ucmd().arg("test_inode").arg("-i").succeeds();
     assert!(re_short.is_match(result.stdout_str()));
@@ -2272,3 +2276,68 @@ fn test_ls_dangling_symlinks() {
         .succeeds() // this should fail, though at the moment, ls lacks a way to propagate errors encountered during display
         .stdout_contains(if cfg!(windows) { "dangle" } else { "? dangle" });
 }
+
+#[test]
+#[cfg(feature = "feat_selinux")]
+fn test_ls_context1() {
+    use selinux::{self, KernelSupport};
+    if selinux::kernel_support() == KernelSupport::Unsupported {
+        println!("test skipped: Kernel has no support for SElinux context",);
+        return;
+    }
+
+    let file = "test_ls_context_file";
+    let expected = format!("unconfined_u:object_r:user_tmp_t:s0 {}\n", file);
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.touch(file);
+    ucmd.args(&["-Z", file]).succeeds().stdout_is(expected);
+}
+
+#[test]
+#[cfg(feature = "feat_selinux")]
+fn test_ls_context2() {
+    use selinux::{self, KernelSupport};
+    if selinux::kernel_support() == KernelSupport::Unsupported {
+        println!("test skipped: Kernel has no support for SElinux context",);
+        return;
+    }
+    let ts = TestScenario::new(util_name!());
+    for c_flag in &["-Z", "--context"] {
+        ts.ucmd()
+            .args(&[c_flag, &"/"])
+            .succeeds()
+            .stdout_only(unwrap_or_return!(expected_result(&ts, &[c_flag, &"/"])).stdout_str());
+    }
+}
+
+#[test]
+#[cfg(feature = "feat_selinux")]
+fn test_ls_context_format() {
+    use selinux::{self, KernelSupport};
+    if selinux::kernel_support() == KernelSupport::Unsupported {
+        println!("test skipped: Kernel has no support for SElinux context",);
+        return;
+    }
+    let ts = TestScenario::new(util_name!());
+    // NOTE:
+    // --format=long/verbose matches the output of GNU's ls for --context
+    // except for the size count which may differ to the size count reported by GNU's ls.
+    for word in &[
+        "across",
+        "commas",
+        "horizontal",
+        // "long",
+        "single-column",
+        // "verbose",
+        "vertical",
+    ] {
+        let format = format!("--format={}", word);
+        ts.ucmd()
+            .args(&[&"-Z", &format.as_str(), &"/"])
+            .succeeds()
+            .stdout_only(
+                unwrap_or_return!(expected_result(&ts, &[&"-Z", &format.as_str(), &"/"]))
+                    .stdout_str(),
+            );
+    }
+}
diff --git a/tests/by-util/test_seq.rs b/tests/by-util/test_seq.rs
index 27b5f99bc..6ed3cb67d 100644
--- a/tests/by-util/test_seq.rs
+++ b/tests/by-util/test_seq.rs
@@ -1,6 +1,69 @@
 use crate::common::util::*;
 use std::io::Read;
 
+#[test]
+fn test_hex_rejects_sign_after_identifier() {
+    new_ucmd!()
+        .args(&["0x-123ABC"])
+        .fails()
+        .no_stdout()
+        .stderr_contains("invalid hexadecimal argument: '0x-123ABC'")
+        .stderr_contains("for more information.");
+    new_ucmd!()
+        .args(&["0x+123ABC"])
+        .fails()
+        .no_stdout()
+        .stderr_contains("invalid hexadecimal argument: '0x+123ABC'")
+        .stderr_contains("for more information.");
+    new_ucmd!()
+        .args(&["-0x-123ABC"])
+        .fails()
+        .no_stdout()
+        .stderr_contains("invalid hexadecimal argument: '-0x-123ABC'")
+        .stderr_contains("for more information.");
+    new_ucmd!()
+        .args(&["-0x+123ABC"])
+        .fails()
+        .no_stdout()
+        .stderr_contains("invalid hexadecimal argument: '-0x+123ABC'")
+        .stderr_contains("for more information.");
+}
+
+#[test]
+fn test_hex_lowercase_uppercase() {
+    new_ucmd!()
+        .args(&["0xa", "0xA"])
+        .succeeds()
+        .stdout_is("10\n");
+    new_ucmd!()
+        .args(&["0Xa", "0XA"])
+        .succeeds()
+        .stdout_is("10\n");
+}
+
+#[test]
+fn test_hex_big_number() {
+    new_ucmd!()
+        .args(&[
+            "0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
+            "0x100000000000000000000000000000000",
+        ])
+        .succeeds()
+        .stdout_is(
+            "340282366920938463463374607431768211455\n340282366920938463463374607431768211456\n",
+        );
+}
+
+#[test]
+fn test_hex_identifier_in_wrong_place() {
+    new_ucmd!()
+        .args(&["1234ABCD0x"])
+        .fails()
+        .no_stdout()
+        .stderr_contains("invalid hexadecimal argument: '1234ABCD0x'")
+        .stderr_contains("for more information.");
+}
+
 #[test]
 fn test_rejects_nan() {
     let ts = TestScenario::new(util_name!());
diff --git a/tests/common/util.rs b/tests/common/util.rs
index f3cdec010..8e9078e9c 100644
--- a/tests/common/util.rs
+++ b/tests/common/util.rs
@@ -1169,7 +1169,7 @@ pub fn check_coreutil_version(
                 if s.contains(&format!("(GNU coreutils) {}", version_expected)) {
                     Ok(format!("{}: {}", UUTILS_INFO, s.to_string()))
                 } else if s.contains("(GNU coreutils)") {
-                    let version_found = s.split_whitespace().last().unwrap()[..4].parse::<f32>().unwrap_or_default();
+                    let version_found = parse_coreutil_version(s);
                     let version_expected = version_expected.parse::<f32>().unwrap_or_default();
                     if version_found > version_expected {
                     Ok(format!("{}: version for the reference coreutil '{}' is higher than expected; expected: {}, found: {}", UUTILS_INFO, util_name, version_expected, version_found))
@@ -1182,6 +1182,20 @@ pub fn check_coreutil_version(
         )
 }
 
+// simple heuristic to parse the coreutils SemVer string, e.g. "id (GNU coreutils) 8.32.263-0475"
+fn parse_coreutil_version(version_string: &str) -> f32 {
+    version_string
+        .split_whitespace()
+        .last()
+        .unwrap()
+        .split('.')
+        .take(2)
+        .collect::<Vec<_>>()
+        .join(".")
+        .parse::<f32>()
+        .unwrap_or_default()
+}
+
 /// This runs the GNU coreutils `util_name` binary in `$PATH` in order to
 /// dynamically gather reference values on the system.
 /// If the `util_name` in `$PATH` doesn't include a coreutils version string,
@@ -1474,6 +1488,36 @@ mod tests {
         res.normalized_newlines_stdout_is("A\r\nB\nC\n");
     }
 
+    #[test]
+    #[cfg(unix)]
+    fn test_parse_coreutil_version() {
+        use std::assert_eq;
+        assert_eq!(
+            parse_coreutil_version("id (GNU coreutils) 9.0.123-0123").to_string(),
+            "9"
+        );
+        assert_eq!(
+            parse_coreutil_version("id (GNU coreutils) 8.32.263-0475").to_string(),
+            "8.32"
+        );
+        assert_eq!(
+            parse_coreutil_version("id (GNU coreutils) 8.25.123-0123").to_string(),
+            "8.25"
+        );
+        assert_eq!(
+            parse_coreutil_version("id (GNU coreutils) 9.0").to_string(),
+            "9"
+        );
+        assert_eq!(
+            parse_coreutil_version("id (GNU coreutils) 8.32").to_string(),
+            "8.32"
+        );
+        assert_eq!(
+            parse_coreutil_version("id (GNU coreutils) 8.25").to_string(),
+            "8.25"
+        );
+    }
+
     #[test]
     #[cfg(unix)]
     fn test_check_coreutil_version() {