diff --git a/TODO.txt b/TODO.txt
index ab88343..9a4418c 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,6 +1,5 @@
 0.4
 - Run integration tests using multiple shells.
-- `rew x --null` example with propagation.
 - Better shell specific examples for `rew x`.
 - Add `rew x --quote` with examples.
 - Fix `--examples` order in generated docs.
@@ -14,4 +13,5 @@
 - Add here more TODOs for command replacement of old rew filters.
 
 1.0
+- Add `case` conversion command based on https://docs.rs/heck/latest/heck/
 - Setup man generator.
diff --git a/docs/reference/rew-x.md b/docs/reference/rew-x.md
index 052b809..4b9025c 100644
--- a/docs/reference/rew-x.md
+++ b/docs/reference/rew-x.md
@@ -409,3 +409,24 @@ rew x '{seq}:\n\t{}'
 </ul>
 </div>
 </div>
+
+All global options `-0, --null`, `--buf-size` and `--buf-mode` are propagated to rew subcommands. Do not forget configure NUL separator manually for any external commands.
+
+```sh
+rew x --null '{upper | sed --null-data "s/^.//g"}'
+```
+
+<div class="example-io">
+<div class="example-io-stream">
+<small><b>stdin:</b></small>
+<ul>
+<li><code>aa\0bb\0cc\0</code></li>
+</ul>
+</div>
+<div class="example-io-stream">
+<small><b>stdout:</b></small>
+<ul>
+<li><code>A\0B\0C\0</code></li>
+</ul>
+</div>
+</div>
diff --git a/src/commands/x.rs b/src/commands/x.rs
index 8925a71..c36c4a5 100644
--- a/src/commands/x.rs
+++ b/src/commands/x.rs
@@ -127,6 +127,12 @@ pub const META: Meta = command_meta! {
             input: &["first", "second", "third"],
             output: &["1:", "\tfirst", "2:", "\tsecond", "3:", "\tthird"],
         },
+        "All global options `-0, --null`, `--buf-size` and `--buf-mode` are propagated to rew subcommands. \
+         Do not forget configure NUL separator manually for any external commands.": {
+            args: &["--null", "{upper | sed --null-data 's/^.//g'}"],
+            input: &["aa", "bb", "cc"],
+            output: &["A", "B", "C"],
+        },
     ],
 };
 
diff --git a/src/examples.rs b/src/examples.rs
index 8000740..7e880a3 100644
--- a/src/examples.rs
+++ b/src/examples.rs
@@ -29,6 +29,12 @@ pub struct Example {
     pub output: &'static [&'static str],
 }
 
+impl Example {
+    pub fn has_null_arg(&self) -> bool {
+        self.args.iter().any(|arg| *arg == "-0" || *arg == "--null")
+    }
+}
+
 #[macro_export]
 macro_rules! examples {
     ($($text:literal: { args: $args:expr, input: $input:expr, output: $output:expr, }),*,) => {
@@ -102,9 +108,10 @@ fn write(writer: &mut impl Write, command: &str, examples: &[Example]) -> Result
         write_text(writer, example.text, term_width)?;
         writeln!(writer)?;
         write_command(writer, command, example.args)?;
-        write_io(writer, example.input, example.output)?;
+        write_io(writer, example)?;
     }
 
+    writeln!(writer)?;
     Ok(())
 }
 
@@ -163,13 +170,14 @@ fn write_command(writer: &mut impl Write, subcmd: &str, args: &[&str]) -> io::Re
     writeln!(writer, " {GREEN}╰{}╯{RESET}", "─".repeat(width))
 }
 
-fn write_io(writer: &mut impl Write, input: &[&str], output: &[&str]) -> io::Result<()> {
-    if input.is_empty() && output.is_empty() {
+fn write_io(writer: &mut impl Write, example: &Example) -> io::Result<()> {
+    if example.input.is_empty() && example.output.is_empty() {
         return Ok(());
     }
 
-    let input = normalize_lines(input);
-    let output = normalize_lines(output);
+    let null_separator = example.has_null_arg();
+    let input = normalize_lines(example.input, null_separator);
+    let output = normalize_lines(example.output, null_separator);
 
     let input_label = "stdin:";
     let output_label = "stdout:";
@@ -211,11 +219,17 @@ fn write_io_line(writer: &mut impl Write, lines: &[String], index: usize) -> io:
     write!(writer, " ")?;
 
     if let Some(line) = lines.get(index) {
-        write!(writer, "{GREEN}\"{RESET}{line}{GREEN}\"{RESET}{RESET}",)?;
-        writer.write_all(" ".repeat(max_line_width(lines) - line.width()).as_bytes())
-    } else {
-        write!(writer, "{}", " ".repeat(max_line_width(lines) + 2))
+        let line = line.replace("\\0", &format!("{YELLOW}\\0{RESET}"));
+        write!(writer, "{GREEN}\"{RESET}{line}{GREEN}\"{RESET}{RESET}")?;
     }
+
+    let padding = if let Some(line) = lines.get(index) {
+        max_line_width(lines) - line.width()
+    } else {
+        max_line_width(lines) + 2
+    };
+
+    write!(writer, "{}", " ".repeat(padding))
 }
 
 fn normalize_args(args: &[&str]) -> Vec<String> {
@@ -232,11 +246,17 @@ fn normalize_args(args: &[&str]) -> Vec<String> {
         .collect::<Vec<_>>()
 }
 
-fn normalize_lines(lines: &[&str]) -> Vec<String> {
-    lines
+fn normalize_lines(lines: &[&str], null_separator: bool) -> Vec<String> {
+    let lines = lines
         .iter()
         .map(|line| line.replace('\t', "    "))
-        .collect::<Vec<_>>()
+        .collect::<Vec<_>>();
+
+    if null_separator {
+        vec![format!("{}\\0", lines.join("\\0"))]
+    } else {
+        lines
+    }
 }
 
 fn max_line_width(lines: &[String]) -> usize {
diff --git a/tests/examples.rs b/tests/examples.rs
index cc3afa3..7692fc6 100644
--- a/tests/examples.rs
+++ b/tests/examples.rs
@@ -6,6 +6,12 @@ use std::env;
 fn examples() {
     for meta in rew::commands::METAS {
         for example in meta.examples {
+            // Such examples require coreutils with NUL separator support
+            // which are not available on MacOS by default.
+            if cfg!(target_os = "macos") && example.has_null_arg() {
+                continue;
+            }
+
             println!("[{}] {}", meta.name, first_line(example.text));
 
             Command::cargo_bin(crate_name!())
@@ -13,10 +19,10 @@ fn examples() {
                 .env("SHELL", "sh") // Examples expect UNIX shell
                 .arg(meta.name)
                 .args(example.args)
-                .write_stdin(join_lines(example.input))
+                .write_stdin(join_lines(example.input, example.has_null_arg()))
                 .assert()
                 .success()
-                .stdout(join_lines(example.output))
+                .stdout(join_lines(example.output, example.has_null_arg()))
                 .stderr("");
         }
     }
@@ -26,6 +32,7 @@ fn first_line(text: &str) -> &str {
     text.split('\n').next().unwrap_or_default()
 }
 
-fn join_lines(lines: &[&str]) -> String {
-    format!("{}\n", lines.join("\n"))
+fn join_lines(lines: &[&str], null_separator: bool) -> String {
+    let separator = if null_separator { "\0" } else { "\n" };
+    format!("{}{separator}", lines.join(separator))
 }
diff --git a/xtask/src/docs.rs b/xtask/src/docs.rs
index a1ba708..f0437fc 100644
--- a/xtask/src/docs.rs
+++ b/xtask/src/docs.rs
@@ -290,11 +290,11 @@ fn write_example(writer: &mut impl Write, command: &Adapter<'_>, example: &Examp
         writeln!(writer, "<div class=\"example-io\">")?;
 
         if !example.input.is_empty() {
-            write_example_io(writer, "stdin", example.input)?;
+            write_example_io(writer, "stdin", example.input, example.has_null_arg())?;
         }
 
         if !example.output.is_empty() {
-            write_example_io(writer, "stdout", example.output)?;
+            write_example_io(writer, "stdout", example.output, example.has_null_arg())?;
         }
 
         writeln!(writer, "</div>")?;
@@ -303,21 +303,34 @@ fn write_example(writer: &mut impl Write, command: &Adapter<'_>, example: &Examp
     Ok(())
 }
 
-fn write_example_io(writer: &mut impl Write, title: &str, lines: &[&str]) -> Result<()> {
+fn write_example_io(
+    writer: &mut impl Write,
+    title: &str,
+    lines: &[&str],
+    null_separator: bool,
+) -> Result<()> {
     writeln!(writer, "<div class=\"example-io-stream\">")?;
     writeln!(writer, "<small><b>{title}:</b></small>")?;
     writeln!(writer, "<ul>")?;
 
-    for line in lines {
-        let line = line
-            .replace(' ', "\u{a0}") // Unbreakable spaces to prevent trimming by mdbook html renderer.
-            .replace('\t', "\u{a0}\u{a0}\u{a0}\u{a0}");
-
-        // <code> because mdbook html renderer cannot render empty `` (which we need for empty IO lines).
+    // We use <code> because mdbook cannot render empty `` which we need for empty IO lines.
+    if null_separator {
+        let line = format!("{}\\0", lines.join("\\0"));
+        let line = normalize_line(&line);
         writeln!(writer, "<li><code>{line}</code></li>")?;
+    } else {
+        for line in lines {
+            let line = normalize_line(line);
+            writeln!(writer, "<li><code>{line}</code></li>")?;
+        }
     }
 
     writeln!(writer, "</ul>")?;
     writeln!(writer, "</div>")?;
     Ok(())
 }
+
+fn normalize_line(line: &str) -> String {
+    line.replace(' ', "\u{a0}") // Unbreakable spaces to prevent trimming by mdbook html renderer.
+        .replace('\t', "\u{a0}\u{a0}\u{a0}\u{a0}")
+}