diff --git a/README.md b/README.md
index fe6525e..33da00c 100644
--- a/README.md
+++ b/README.md
@@ -43,7 +43,7 @@ This began as, and continues to be, a learning exercise to better understand the
 | df | :white_large_square: |
 | dir | :white_large_square: |
 | dircolors | :white_large_square: |
-| dirname | :white_large_square: |
+| dirname | :white_check_mark: |
 | du | :white_large_square: |
 | echo | :white_large_square: |
 | env | :white_large_square: |
diff --git a/dirname/Cargo.toml b/dirname/Cargo.toml
index 3703bdb..dd10aa2 100644
--- a/dirname/Cargo.toml
+++ b/dirname/Cargo.toml
@@ -1,10 +1,12 @@
 [package]
 name = "dirname"
 version = "0.1.0"
-edition = "2021"
+edition = "2024"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
 clap = { workspace = true }
-shellexpand = "2.1.2"
+coreutils = { workspace = true }
+tabled = { workspace = true }
+serde_json = { workspace = true }
diff --git a/dirname/src/main.rs b/dirname/src/main.rs
index b5aa6c6..79bbb23 100644
--- a/dirname/src/main.rs
+++ b/dirname/src/main.rs
@@ -1,43 +1,86 @@
 use std::path::MAIN_SEPARATOR;
 
-use clap::Parser;
-
-/// A rust implementation of dirname
-#[derive(Parser, Debug)]
-#[command(author, version, about, long_about = None)]
-struct Args {
-    /// The path to return the directory of
-    paths: Vec<String>,
-}
+use clap::{Arg, ArgAction};
+use tabled::{builder::Builder, settings::Style};
+
+use coreutils::{clap_args, clap_base_command};
+
+clap_args!(Args {
+    flag zero: bool,
+    multi paths: Vec<String>,
+});
 
 fn main() {
-    let args = Args::parse();
+    let matches = clap_base_command()
+        .arg(
+            Arg::new("zero")
+                .short('z')
+                .long("zero")
+                .action(ArgAction::SetTrue)
+                .help("output a null-delimited list of dirnames (plain output only)"),
+        )
+        .arg(
+            Arg::new("paths")
+                .action(ArgAction::Append)
+                .help("the path(s) to return the directory of")
+                .required(true),
+        )
+        .get_matches();
 
-    for arg in &args.paths {
-        let path = shellexpand::tilde(&arg);
+    let args = Args::from_matches(&matches);
 
-        let dirname = get_dirname(&path);
-        println!("{}", dirname);
+    let mut dirnames = Vec::new();
+    for path in &args.paths {
+        let dirname = get_dirname(path);
+        dirnames.push(dirname);
     }
-}
 
-fn get_dirname(path: &str) -> String {
-    match path.rfind(MAIN_SEPARATOR) {
-        Some(idx) => {
-            if idx == 0 {
-                // The last separator is the first character, making it the dir
-                MAIN_SEPARATOR.to_string()
-            } else if !path.starts_with(MAIN_SEPARATOR) {
-                /*
-                if the string doesn't start with the separator, i.e., "foo/"
-                then the dirname is always '.'
-                */
-                '.'.to_string()
-            } else {
-                let dirname = &path[..idx];
-                dirname.to_string()
+    if let Some(output) = &args.output {
+        match output.as_str() {
+            "table" => {
+                let mut builder = Builder::new();
+                builder.push_column(["Dirname(s)"]);
+
+                for dirname in dirnames {
+                    builder.push_record([dirname]);
+                }
+                let mut table = builder.build();
+                println!("{}", table.with(Style::rounded()));
+            }
+            "json" => {
+                println!("{}", serde_json::to_string(&dirnames).unwrap());
+            }
+            "yaml" => {
+                println!("dirnames:");
+                for dirname in dirnames {
+                    println!("  - dirname: \"{}\"", dirname);
+                }
+            }
+            _ => {
+                for dirname in &dirnames {
+                    if args.zero {
+                        print!("{}\0", dirname);
+                    } else {
+                        println!("{}", dirname);
+                    }
+                }
             }
         }
+    }
+}
+
+fn get_dirname(path: &str) -> String {
+    // Strip trailing separators (but preserve root "/")
+    let trimmed = path.trim_end_matches(MAIN_SEPARATOR);
+    let trimmed = if trimmed.is_empty() {
+        &path[..1]
+    } else {
+        trimmed
+    };
+
+    match trimmed.rfind(MAIN_SEPARATOR) {
+        Some(0) => MAIN_SEPARATOR.to_string(),
+        Some(idx) => trimmed[..idx].to_string(),
         None => '.'.to_string(),
     }
 }
@@ -47,13 +90,60 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_dirname() {
-        // Assert that we got the stats we were expecting
+    fn test_root() {
         assert_eq!(get_dirname("/"), "/");
+    }
+
+    #[test]
+    fn test_absolute_single_component() {
         assert_eq!(get_dirname("/foo"), "/");
+    }
+
+    #[test]
+    fn test_bare_filename() {
         assert_eq!(get_dirname("foo"), ".");
+    }
+
+    #[test]
+    fn test_relative_with_trailing_slash() {
         assert_eq!(get_dirname("foo/"), ".");
+    }
+
+    #[test]
+    fn test_absolute_two_components() {
         assert_eq!(get_dirname("/home/stone"), "/home");
+    }
+
+    #[test]
+    fn test_absolute_three_components() {
         assert_eq!(get_dirname("/home/stone/bin"), "/home/stone");
     }
+
+    #[test]
+    fn test_relative_nested() {
+        assert_eq!(get_dirname("foo/bar"), "foo");
+        assert_eq!(get_dirname("foo/bar/baz"), "foo/bar");
+    }
+
+    #[test]
+    fn test_trailing_slashes_absolute() {
+        assert_eq!(get_dirname("/home/stone/"), "/home");
+        assert_eq!(get_dirname("/home/stone///"), "/home");
+    }
+
+    #[test]
+    fn test_trailing_slashes_root() {
+        assert_eq!(get_dirname("///"), "/");
+    }
+
+    #[test]
+    fn test_absolute_single_component_trailing_slash() {
+        assert_eq!(get_dirname("/foo/"), "/");
+    }
+
+    #[test]
+    fn test_dot_and_dotdot() {
+        assert_eq!(get_dirname("."), ".");
+        assert_eq!(get_dirname(".."), ".");
+    }
 }