diff --git a/crates/jmrenamer/Cargo.toml b/crates/jmrenamer/Cargo.toml
index 62a666d..e65773e 100644
--- a/crates/jmrenamer/Cargo.toml
+++ b/crates/jmrenamer/Cargo.toml
@@ -4,4 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+clap = { version = "4.3.8", features = ["derive"] }
 jmmt = { path = "../jmmt" }
diff --git a/crates/jmrenamer/src/main.rs b/crates/jmrenamer/src/main.rs
index 3329b35..f97ca1f 100644
--- a/crates/jmrenamer/src/main.rs
+++ b/crates/jmrenamer/src/main.rs
@@ -6,16 +6,27 @@ use jmmt::hash::filename::*;
 use jmmt::read::package_toc::read_package_toc;
 use std::{fs, path::Path};
 
-// TODO: A mode that will re-name everything back? This wouldn't be too hard to implement
+use clap::{Subcommand, Parser};
 
-fn main() {
-	// A relatively simple idiot-check. Later on utilities might have a shared library
-	// of code which validates game root stuff and can open it up/etc.
-	if !Path::new("DATA").is_dir() {
-		println!("This program should be run in the root of an extracted copy.");
-		return ();
-	}
 
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+#[command(propagate_version = true)]
+struct Cli {
+	#[command(subcommand)]
+	command: Commands,
+}
+
+#[derive(Subcommand)]
+enum Commands {
+	/// Rename the files in the DATA directory to the original filenames.
+	Clear,
+
+	/// Rename the files to the .DAT filenames that the game expects.
+	Unclear,
+}
+
+fn do_clear() {
 	let package_toc_filename = format!("DATA/{}", dat_filename("package.toc"));
 
 	match read_package_toc(Path::new(package_toc_filename.as_str()).to_path_buf()) {
@@ -42,7 +53,7 @@ fn main() {
 							return ();
 						}
 					};
-					println!("moved {} -> {}", src_path.display(), dest_path.display());
+					println!("Clearnamed {} -> {}", src_path.display(), dest_path.display());
 				}
 			}
 
@@ -64,3 +75,77 @@ fn main() {
 		}
 	}
 }
+
+fn do_unclear() {
+	let package_toc_filename = String::from("DATA/package.toc");
+
+	match read_package_toc(Path::new(package_toc_filename.as_str()).to_path_buf()) {
+		Ok(toc) => {
+			for toc_entry in toc {
+
+				let dat_clearname = format!(
+					"DATA/{}",
+					toc_entry
+						.file_name()
+						.expect("How did invalid ASCII get here?")
+				);
+				let src_path = Path::new(dat_clearname.as_str());
+
+
+				let dat_dest = format!(
+					"DATA/{}",
+					dat_filename_from_hash(toc_entry.file_name_hash())
+				);
+				
+				let dest_path = Path::new(dat_dest.as_str());
+
+				if src_path.exists() {
+					match fs::rename(src_path, dest_path) {
+						Ok(_) => {}
+						Err(error) => {
+							println!("Error renaming {}: {}", src_path.display(), error);
+							return ();
+						}
+					};
+					println!("Uncleared {} -> {}", src_path.display(), dest_path.display());
+				}
+			}
+
+			let package_toc_dat_filename = format!("DATA/{}", dat_filename("package.toc"));
+			match fs::rename(
+				Path::new("DATA/package.toc"),
+				Path::new(package_toc_dat_filename.as_str()),
+			) {
+				Ok(_) => {}
+				Err(error) => {
+					println!("Error renaming TOC file: {}", error);
+					return ();
+				}
+			};
+		}
+
+		Err(error) => {
+			println!("Error reading package.toc file: {}", error);
+			return ();
+		}
+	}
+}
+
+fn main() {
+	// A relatively simple idiot-check. Later on utilities might have a shared library
+	// of code which validates game root stuff and can open it up/etc.
+	if !Path::new("DATA").is_dir() {
+		println!("This program should be run in the root of an extracted copy.");
+		return ();
+	}
+
+	let cli = Cli::parse();
+
+
+	match &cli.command {
+		Commands::Clear =>
+			do_clear(),
+		Commands::Unclear => 
+			do_unclear()
+	}
+}