diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 0000000..3c9a9cf
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,6 @@
+[profile.release]
+strip = true  # strip symbols from the binary
+opt-level = "z" # optimize for size
+lto = true # link time optimization
+codegen-units = 1 # decrease parallelization
+panic = "abort"
diff --git a/Cargo.lock b/Cargo.lock
index e5756f8..b51221d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,15 +2,139 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "arg"
+version = "0.1.0"
+dependencies = [
+ "arg 0.3.1",
+]
+
+[[package]]
+name = "arg"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae60fcba735ceff2193950be268184f45271dd9e9c0823e6d1e9c5d1070caf81"
+dependencies = [
+ "arg-derive",
+]
+
+[[package]]
+name = "arg-derive"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f5f4f6d38dfe8c7ddd11686611d41897abd43db81e28d3cfe8903d78ee5cb06b"
+dependencies = [
+ "quote",
+ "syn",
+ "tabwriter",
+]
+
 [[package]]
 name = "coreutils"
 version = "0.0.1"
 dependencies = [
+ "arg 0.1.0",
+ "exit-no-std",
  "sysexits",
 ]
 
+[[package]]
+name = "exit-no-std"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a608ccc67fac78c1916aa88ad75d6f6a3e353521844abce906c22a45d161d99"
+dependencies = [
+ "libc",
+ "pc-ints",
+ "winapi",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.138"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db6d7e329c562c5dfab7a46a2afabc8b987ab9a4834c9d1ca04dc54c1546cef8"
+
+[[package]]
+name = "pc-ints"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "422b0cc3a966f6e0987d2f948c234585bd917a1f16df1470e60c56ad6de2c085"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ea3d908b0e36316caf9e9e2c4625cdde190a7e6f440d794667ed17a1855e725"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbe448f377a7d6961e30f5955f9b8d106c3f5e449d493ee1b125c1d43c2b5179"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.105"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60b9b43d45702de4c839cb9b51d9f529c5dd26a4aff255b42b1ebc03e88ee908"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "sysexits"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "913b6c9c3fdc55ec78e76e281706cecfe0cfb4ba07545cbce8342ed943dcfa72"
+
+[[package]]
+name = "tabwriter"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36205cfc997faadcc4b0b87aaef3fbedafe20d38d4959a7ca6ff803564051111"
+dependencies = [
+ "unicode-width",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ceab39d59e4c9499d4e5a8ee0e2735b891bb7308ac83dfb4e80cad195c9f6f3"
+
+[[package]]
+name = "unicode-width"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0edd1e5b14653f783770bce4a4dabb4a5108a5370a5f5d8cfe8710c361f6c8b"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/Cargo.toml b/Cargo.toml
index 072d706..8d5deba 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,6 +10,7 @@ authors = [
 
 [dependencies]
 sysexits = "0.3.4"
+arg = { version = "0.1.0", path = "arg", package = "arg" }
 
 [[bin]]
 name = "cat"
diff --git a/arg/Cargo.lock b/arg/Cargo.lock
new file mode 100644
index 0000000..257fed8
--- /dev/null
+++ b/arg/Cargo.lock
@@ -0,0 +1,80 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "arg"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae60fcba735ceff2193950be268184f45271dd9e9c0823e6d1e9c5d1070caf81"
+dependencies = [
+ "arg-derive",
+]
+
+[[package]]
+name = "arg-derive"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f5f4f6d38dfe8c7ddd11686611d41897abd43db81e28d3cfe8903d78ee5cb06b"
+dependencies = [
+ "quote",
+ "syn",
+ "tabwriter",
+]
+
+[[package]]
+name = "arg-dynamic"
+version = "0.1.0"
+dependencies = [
+ "arg",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.47"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ea3d908b0e36316caf9e9e2c4625cdde190a7e6f440d794667ed17a1855e725"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbe448f377a7d6961e30f5955f9b8d106c3f5e449d493ee1b125c1d43c2b5179"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "syn"
+version = "1.0.105"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60b9b43d45702de4c839cb9b51d9f529c5dd26a4aff255b42b1ebc03e88ee908"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "tabwriter"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36205cfc997faadcc4b0b87aaef3fbedafe20d38d4959a7ca6ff803564051111"
+dependencies = [
+ "unicode-width",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ceab39d59e4c9499d4e5a8ee0e2735b891bb7308ac83dfb4e80cad195c9f6f3"
+
+[[package]]
+name = "unicode-width"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0edd1e5b14653f783770bce4a4dabb4a5108a5370a5f5d8cfe8710c361f6c8b"
diff --git a/arg/Cargo.toml b/arg/Cargo.toml
new file mode 100644
index 0000000..742bb4e
--- /dev/null
+++ b/arg/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "arg"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+arg = "0.3.1"
+
+[lib]
+crate-type = ["dylib"]
diff --git a/arg/src/lib.rs b/arg/src/lib.rs
new file mode 100644
index 0000000..32873cb
--- /dev/null
+++ b/arg/src/lib.rs
@@ -0,0 +1 @@
+pub use arg::*;
diff --git a/src/cat.rs b/src/cat.rs
new file mode 100644
index 0000000..a5b3d8a
--- /dev/null
+++ b/src/cat.rs
@@ -0,0 +1,72 @@
+// Copyright (c) 2022 Emma Tebibyte
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+use std::env;
+use std::fs::{File, read_to_string};
+use std::io;
+use std::io::{ BufRead, Write };
+use std::os::unix::io::FromRawFd;
+
+use arg::Args;
+
+use sysexits::ExitCode;
+
+#[derive(Args, Debug)]
+struct Arguments {
+  #[arg(short = "u")]
+  u: bool,
+
+  paths: Vec<String>,
+}
+
+fn main() -> ExitCode {
+  let mut arguments = env::args().collect::<Vec<String>>();
+  let argv0 = arguments.remove(0);
+
+  let args = Arguments::from_args(arguments
+    .iter()
+    .map(String::as_str)
+    .collect::<Vec<&str>>()
+  ).unwrap();
+
+  let mut val = String::new();
+  let mut output = String::new();
+
+  if args.paths.is_empty() {
+    match io::stdin().lock().read_line(&mut output) {
+      Ok(_) => { val.push_str(&output); },
+      Err(_) => {
+        eprintln!("Usage: {} [options...] [files...]", argv0);
+        return ExitCode::Usage;
+      },
+    };
+  } else {
+    for path in args.paths {
+      match read_to_string(&path) {
+        Ok(output) => { val.push_str(&output); },
+        Err(_) => {
+          eprintln!("{}: {}: No such file or directory.", argv0, &path);
+          return ExitCode::NoInput;
+        },
+      };
+    }
+  }
+  if args.u {
+    let mut stdout = unsafe { File::from_raw_fd(1) };
+    match stdout.write_all(&val.as_bytes()) {
+      Ok(_) => {},
+      Err(_) => {
+        eprintln!("{}: Cannot write to stdout", argv0);
+        return ExitCode::OsErr;
+      },
+    };
+  } else { print!("{}", &val); }
+
+  match io::stdout().flush() {
+    Ok(_) => return ExitCode::Ok,
+    Err(_) => {
+      eprintln!("{}: Cannot write to stdout", argv0);
+      return ExitCode::OsErr;
+    },
+  };
+}