simplify return None

src/uu/date/src/format_modifiers.rs

@@ -105,9 +105,7 @@ struct ParsedSpec<'a> {
 /// valid specifier follows.
 fn parse_format_spec(s: &str) -> Option<ParsedSpec<'_>> {
     let bytes = s.as_bytes();
-    if bytes.first() != Some(&b'%') {
-        return None;
-    }
+    bytes.first().filter(|b| *b == &b'%')?;
 
     let mut pos = 1;
 
@@ -134,9 +132,7 @@ fn parse_format_spec(s: &str) -> Option<ParsedSpec<'_>> {
     while bytes.get(pos) == Some(&b':') && pos - spec_start < 3 {
         pos += 1;
     }
-    if bytes.get(pos).is_none_or(|c| !c.is_ascii_alphabetic()) {
-        return None;
-    }
+    bytes.get(pos).filter(|c| c.is_ascii_alphabetic())?;
     pos += 1;
     let spec = &s[spec_start..pos];
 

src/uu/fmt/src/parasplit.rs

@@ -252,10 +252,10 @@ impl Iterator for FileLines<'_> {
 
     fn next(&mut self) -> Option<Line> {
         let mut buf = Vec::new();
-        match self.reader.read_until(b'\n', &mut buf) {
-            Ok(0) | Err(_) => return None,
-            Ok(_) => {}
-        }
+        self.reader
+            .read_until(b'\n', &mut buf)
+            .ok()
+            .filter(|n| *n > 0)?;
         if buf.ends_with(b"\n") {
             buf.pop();
             if buf.ends_with(b"\r") {

src/uucore/src/lib/features/checksum/validate.rs

@@ -281,12 +281,13 @@ impl LineFormat {
         // find the next parenthesis  using byte search (not next whitespace) because openssl's
         // tagged format does not put a space before (filename)
 
-        let par_idx = rest.iter().position(|&b| b == b'(')?;
-        // If the parenthesis is the first character (minus whitespace, which has already been stripped out), then,
-        // it's not a validly formatted line.
-        if par_idx == 0 {
-            return None;
-        }
+        let par_idx = rest
+            .iter()
+            .position(|&b| b == b'(')
+            // If the parenthesis is the first character (minus whitespace, which has already been stripped out), then,
+            // it's not a validly formatted line.
+            .filter(|b| *b != 0)?;
+
         let sub_case = if rest[par_idx - 1] == b' ' {
             SubCase::Posix
         } else {

tests/by-util/test_df.rs

@@ -1099,13 +1099,11 @@ fn run_df_with_masked_proc(args: &str) -> Option<(bool, String, String)> {
     use std::process::Command;
 
     // Check if user namespaces are available
-    if !Command::new("unshare")
+    Command::new("unshare")
         .args(["-rm", "true"])
         .status()
-        .is_ok_and(|s| s.success())
-    {
-        return None;
-    }
+        .ok()
+        .filter(std::process::ExitStatus::success)?;
 
     let df_path = TestScenario::new("df").bin_path.clone();
     let output = Command::new("unshare")

tests/by-util/test_sort.rs

@@ -643,10 +643,8 @@ fn get_system_abmon(locale: &str) -> Option<Vec<String>> {
         .env("LC_ALL", locale)
         .arg("abmon")
         .output()
-        .ok()?;
-    if !output.status.success() {
-        return None;
-    }
+        .ok()
+        .filter(|s| s.status.success())?;
     let text = String::from_utf8(output.stdout).ok()?;
     let months: Vec<String> = text
         .trim()
@@ -2077,10 +2075,8 @@ fn test_human_numeric_blank_thousands_sep_locale() {
             .arg("thousands_sep")
             .env("LC_ALL", locale)
             .output()
-            .ok()?;
-        if !output.status.success() {
-            return None;
-        }
+            .ok()
+            .filter(|s| s.status.success())?;
         let sep = String::from_utf8_lossy(&output.stdout);
         let sep = sep.trim_end_matches(&['\n', '\r'][..]);
         if sep.is_empty() || sep.len() != 1 || !sep.chars().all(char::is_whitespace) {