uutils/coreutils · error · std::io::Error

error writing 'standard output': {$err}

Error message

error writing 'standard output': {$err}

What it means

Error "error writing 'standard output': {$err}" thrown in uutils/coreutils.

Source

Thrown at src/uu/head/src/head.rs:209

        options.verbose = matches.get_flag(options::VERBOSE);
        options.line_ending = LineEnding::from_zero_flag(matches.get_flag(options::ZERO));
        options.presume_input_pipe = matches.get_flag(options::PRESUME_INPUT_PIPE);

        options.mode = Mode::from(matches)?;
        // #[allow(clippy::unwrap_used, reason = "clap provides '-' by default")] <https://github.com/rust-lang/rust/issues/15701>
        options.files = matches
            .get_many::<OsString>(options::FILES)
            .unwrap()
            .cloned()
            .collect();

        Ok(options)
    }
}

#[inline]
fn wrap_in_stdout_error(err: io::Error) -> io::Error {
    io::Error::new(
        err.kind(),
        translate!("head-error-writing-stdout", "err" => uucore::error::strip_errno(&err)),
    )
}

// zero-copy fast-path
#[cfg(any(target_os = "linux", target_os = "android"))]
fn print_n_bytes(input: impl AsFd, n: u64) -> io::Result<u64> {
    let out = io::stdout();
    uucore::pipes::send_n_bytes(input, &out, n).map_err(wrap_in_stdout_error)
}

#[cfg(not(any(target_os = "linux", target_os = "android")))]
fn print_n_bytes(input: impl Read, n: u64) -> io::Result<u64> {
    // Read the first `n` bytes from the `input` reader.
    let mut reader = input.take(n);

    // Write those bytes to `stdout`.

View on GitHub (pinned to 8b8cbfd51b)

Solutions

1. Check that stdout is writable and the consumer did not close the pipe (avoid SIGPIPE).
2. Free disk space if the error is ENOSPC when stdout is redirected to a file.

When it happens

Trigger: Occurs when head fails to write to standard output, typically because stdout was closed early (EPIPE) or an I/O error occurred.

Common situations: Piping head into a command that exits immediately (e.g. `head -n100 file | true`), or redirecting output to a full or failing device.

AI-assisted analysis of uutils/coreutils@8b8cbfd51b (2026-08-19). Data as JSON: /api/errors/dd308ae2b42646c4. Report an issue: GitHub.