uutils · fnordahl · May 9, 2025 · May 9, 2025
diff --git a/src/bin/coreutils.rs b/src/bin/coreutils.rs
@@ -20,18 +20,18 @@ const VERSION: &str = env!("CARGO_PKG_VERSION");
 include!(concat!(env!("OUT_DIR"), "/uutils_map.rs"));
 
 fn usage<T>(utils: &UtilityMap<T>, name: &str) {
-    println!("{name} {VERSION} (multi-call binary)\n");
-    println!("Usage: {name} [function [arguments...]]");
-    println!("       {name} --list\n");
-    println!("Options:");
-    println!("      --list    lists all defined functions, one per row\n");
-    println!("Currently defined functions:\n");
+    eprintln!("{name} {VERSION} (multi-call binary)\n");
+    eprintln!("Usage: {name} [function [arguments...]]");
+    eprintln!("       {name} --list\n");
+    eprintln!("Options:");
+    eprintln!("      --list    lists all defined functions, one per row\n");
+    eprintln!("Currently defined functions:\n");
     #[allow(clippy::map_clone)]
     let mut utils: Vec<&str> = utils.keys().map(|&s| s).collect();
     utils.sort_unstable();
     let display_list = utils.join(", ");
     let width = cmp::min(textwrap::termwidth(), 100) - 4 * 2; // (opinion/heuristic) max 100 chars wide with 4 character side indentions
-    println!(
+    eprintln!(
         "{}",
         textwrap::indent(&textwrap::fill(&display_list, width), "    ")
     );

diff --git a/src/uu/cat/src/cat.rs b/src/uu/cat/src/cat.rs
@@ -450,6 +450,18 @@ fn cat_files(files: &[String], options: &OutputOptions) -> UResult<()> {
 
     for path in files {
         if let Err(err) = cat_path(path, options, &mut state, out_info.as_ref()) {
+            if let CatError::Io(ref err_io) = err {
+                if err_io.kind() == io::ErrorKind::BrokenPipe {
+                    continue;
+                }
+            }
+            #[cfg(any(target_os = "linux", target_os = "android"))]
+            if let CatError::Nix(ref err_nix) = err {
+                // spell-checker:disable-next-line
+                if *err_nix == nix::errno::Errno::EPIPE {
+                    continue;
+                }
+            }
             error_messages.push(format!("{}: {err}", path.maybe_quote()));
         }
     }

diff --git a/tests/by-util/test_cat.rs b/tests/by-util/test_cat.rs
@@ -716,3 +716,86 @@ fn test_child_when_pipe_in() {
 
     ts.ucmd().pipe_in("content").run().stdout_is("content");
 }
+
+#[cfg(target_os = "linux")]
+mod linux_only {
+    use uutests::util::{CmdResult, TestScenario, UCommand};
+
+    use std::fmt::Write;
+    use std::fs::File;
+    use std::process::Stdio;
+    use uutests::new_ucmd;
+    use uutests::util_name;
+
+    fn make_broken_pipe() -> File {
+        use libc::c_int;
+        use std::os::unix::io::FromRawFd;
+
+        let mut fds: [c_int; 2] = [0, 0];
+        assert!(
+            (unsafe { libc::pipe(std::ptr::from_mut::<c_int>(&mut fds[0])) } == 0),
+            "Failed to create pipe"
+        );
+
+        // Drop the read end of the pipe
+        let _ = unsafe { File::from_raw_fd(fds[0]) };
+
+        // Make the write end of the pipe into a Rust File
+        unsafe { File::from_raw_fd(fds[1]) }
+    }
+
+    fn run_cat(proc: &mut UCommand) -> (String, CmdResult) {
+        let content = (1..=100_000).fold(String::new(), |mut output, x| {
+            let _ = writeln!(output, "{x}");
+            output
+        });
+
+        let result = proc
+            .ignore_stdin_write_error()
+            .set_stdin(Stdio::piped())
+            .run_no_wait()
+            .pipe_in_and_wait(content.as_bytes());
+
+        (content, result)
+    }
+
+    fn expect_silent_success(result: &CmdResult) {
+        assert!(
+            result.succeeded(),
+            "Command was expected to succeed.\nstdout = {}\n stderr = {}",
+            std::str::from_utf8(result.stdout()).unwrap(),
+            std::str::from_utf8(result.stderr()).unwrap(),
+        );
+        assert!(
+            result.stderr_str().is_empty(),
+            "Unexpected data on stderr.\n stderr = {}",
+            std::str::from_utf8(result.stderr()).unwrap(),
+        );
+    }
+
+    fn expect_short(result: &CmdResult, contents: &str) {
+        let compare = result.stdout_str();
+        assert!(
+            compare.len() < contents.len(),
+            "Too many bytes ({}) written to stdout (should be a short count from {})",
+            compare.len(),
+            contents.len()
+        );
+        assert!(
+            contents.starts_with(&compare),
+            "Expected truncated output to be a prefix of the correct output, but it isn't.\n Correct: {contents}\n Compare: {compare}"
+        );
+    }
+
+    #[test]
+    fn test_pipe_error_default() {
+        let mut ucmd = new_ucmd!();
+
+        let proc = ucmd.set_stdout(make_broken_pipe());
+
+        let (content, output) = run_cat(proc);
+
+        expect_silent_success(&output);
+        expect_short(&output, &content);
+    }
+}
diff --git a/tests/test_util_name.rs b/tests/test_util_name.rs
@@ -120,8 +120,8 @@ fn util_invalid_name_help() {
         .unwrap();
     let output = child.wait_with_output().unwrap();
     assert_eq!(output.status.code(), Some(0));
-    assert_eq!(output.stderr, b"");
-    let output_str = String::from_utf8(output.stdout).unwrap();
+    assert_eq!(output.stdout, b"");
+    let output_str = String::from_utf8(output.stderr).unwrap();
     assert!(output_str.contains("(multi-call binary)"), "{output_str:?}");
     assert!(
         output_str.contains("Usage: invalid_name [function "),
@@ -159,8 +159,8 @@ fn util_non_utf8_name_help() {
         .unwrap();
     let output = child.wait_with_output().unwrap();
     assert_eq!(output.status.code(), Some(0));
-    assert_eq!(output.stderr, b"");
-    let output_str = String::from_utf8(output.stdout).unwrap();
+    assert_eq!(output.stdout, b"");
+    let output_str = String::from_utf8(output.stderr).unwrap();
     assert!(output_str.contains("(multi-call binary)"), "{output_str:?}");
     assert!(
         output_str.contains("Usage: <unknown binary name> [function "),