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nl: output number separator as bytes #9601

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1882ff5
nl: output number separator as bytes
cakebaker Dec 8, 2025
db52eac
nl: output content as bytes, not as string
cakebaker Dec 8, 2025
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24 changes: 16 additions & 8 deletions src/uu/nl/src/nl.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -409,16 +409,24 @@ fn nl<T: Read>(reader: &mut BufReader<T>, stats: &mut Stats, settings: &Settings
translate!("nl-error-line-number-overflow"),
));
};
writeln!(
writer,
"{}{}{}",
let mut buf = Vec::with_capacity(
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@ChrisDryden ChrisDryden Dec 10, 2025

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Amazing performance improvement, we should look for more changes like this in the codebase. For anyone looking in the future for more perf improvements its now at the point that a big percentage of the time is spent freeing the vec, and if you do .clear it actually just sets the len to 0 so that you can just use the same buffer in the loop and add more capacity if needed by checking buf.capacity().

settings.number_width + settings.number_separator.len() + line.len() + 1,
);

buf.extend(
settings
.number_format
.format(line_number, settings.number_width),
settings.number_separator.to_string_lossy(),
String::from_utf8_lossy(&line),
)
.map_err_context(|| translate!("nl-error-could-not-write"))?;
.format(line_number, settings.number_width)
.as_bytes(),
);
buf.extend(settings.number_separator.as_encoded_bytes());
buf.extend(&line);
buf.push(b'\n');

writer
.write_all(&buf)
.map_err_context(|| translate!("nl-error-could-not-write"))?;

// update line number for the potential next line
match line_number.checked_add(settings.line_increment) {
Some(new_line_number) => stats.line_number = Some(new_line_number),
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25 changes: 15 additions & 10 deletions tests/by-util/test_nl.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -209,23 +209,24 @@ fn test_number_separator() {
#[test]
#[cfg(target_os = "linux")]
fn test_number_separator_non_utf8() {
use std::{
ffi::{OsStr, OsString},
os::unix::ffi::{OsStrExt, OsStringExt},
};
use std::{ffi::OsString, os::unix::ffi::OsStringExt};

let separator_bytes = [0xFF, 0xFE];
let mut v = b"--number-separator=".to_vec();
v.extend_from_slice(&separator_bytes);

let arg = OsString::from_vec(v);
let separator = OsStr::from_bytes(&separator_bytes);

let mut expected = Vec::with_capacity(14);
expected.extend(b" 1");
expected.extend(separator_bytes);
expected.extend(b"test\n");

new_ucmd!()
.arg(arg)
.pipe_in("test")
.succeeds()
.stdout_is(format!(" 1{}test\n", separator.to_string_lossy()));
.stdout_is_bytes(expected);
}

#[test]
Expand Down Expand Up @@ -795,10 +796,14 @@ fn test_file_with_non_utf8_content() {

at.write_bytes(filename, content);

ucmd.arg(filename).succeeds().stdout_is(format!(
" 1\ta\n 2\t{}\n 3\tb\n",
String::from_utf8_lossy(invalid_utf8)
));
let mut expected = Vec::with_capacity(30);
expected.extend(b" 1\ta\n");
expected.extend(b" 2\t");
expected.extend(invalid_utf8);
expected.extend(b"\n");
expected.extend(b" 3\tb\n");

ucmd.arg(filename).succeeds().stdout_is_bytes(expected);
}

// Regression tests for issue #9132: repeated flags should use last value
Expand Down
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