diff --git a/.vscode/settings.json b/.vscode/settings.json
index 728bf24..8d59ce2 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,6 +1,7 @@
 {
     "cSpell.words": [
         "Aspe",
+        "Aspm",
         "josekit",
         "PKCS",
         "Pkey"
diff --git a/Cargo.lock b/Cargo.lock
index bc60184..0b2d280 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -17,12 +17,73 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "anstream"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ca84f3628370c59db74ee214b3263d58f9aadd9b4fe7e711fd87dc452b7f163"
+dependencies = [
+ "anstyle",
+ "anstyle-parse",
+ "anstyle-query",
+ "anstyle-wincon",
+ "colorchoice",
+ "is-terminal",
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3a30da5c5f2d5e72842e00bcb57657162cdabef0931f40e2deb9b4140440cecd"
+
+[[package]]
+name = "anstyle-parse"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "938874ff5980b03a87c5524b3ae5b59cf99b1d6bc836848df7bc5ada9643c333"
+dependencies = [
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle-query"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ca11d4be1bab0c8bc8734a9aa7bf4ee8316d462a08c6ac5052f888fef5b494b"
+dependencies = [
+ "windows-sys 0.48.0",
+]
+
+[[package]]
+name = "anstyle-wincon"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "180abfa45703aebe0093f79badacc01b8fd4ea2e35118747e5811127f926e188"
+dependencies = [
+ "anstyle",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c7d0618f0e0b7e8ff11427422b64564d5fb0be1940354bfe2e0529b18a9d9b8"
 
+[[package]]
+name = "app_dirs2"
+version = "2.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7e7b35733e3a8c1ccb90385088dd5b6eaa61325cb4d1ad56e683b5224ff352e"
+dependencies = [
+ "jni",
+ "ndk-context",
+ "winapi",
+ "xdg",
+]
+
 [[package]]
 name = "arrayvec"
 version = "0.7.4"
@@ -51,6 +112,12 @@ dependencies = [
 [[package]]
 name = "aspm"
 version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "app_dirs2",
+ "clap",
+ "thiserror",
+]
 
 [[package]]
 name = "autocfg"
@@ -97,12 +164,76 @@ version = "1.0.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "50d30906286121d95be3d479533b458f87493b30a4b5f79a607db8f5d11aa91f"
 
+[[package]]
+name = "cesu8"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d43a04d8753f35258c91f8ec639f792891f748a1edbd759cf1dcea3382ad83c"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "clap"
+version = "4.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bba77a07e4489fb41bd90e8d4201c3eb246b3c2c9ea2ba0bddd6c1d1df87db7d"
+dependencies = [
+ "clap_builder",
+ "clap_derive",
+ "once_cell",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c9b4a88bb4bc35d3d6f65a21b0f0bafe9c894fa00978de242c555ec28bea1c0"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "bitflags",
+ "clap_lex",
+ "strsim",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8cd2b2a819ad6eec39e8f1d6b53001af1e5469f8c177579cdaeb313115b825f"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2da6da31387c7e4ef160ffab6d5e7f00c42626fe39aea70a7b0f1773f7dd6c1b"
+
+[[package]]
+name = "colorchoice"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
+
+[[package]]
+name = "combine"
+version = "4.6.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35ed6e9d84f0b51a7f52daf1c7d71dd136fd7a3f41a8462b8cdb8c78d920fad4"
+dependencies = [
+ "bytes",
+ "memchr",
+]
+
 [[package]]
 name = "core-foundation"
 version = "0.9.3"
@@ -348,6 +479,12 @@ version = "0.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2c6201b9ff9fd90a5a3bac2e56a830d0caa509576f0e503818ee82c181b3437a"
 
+[[package]]
+name = "heck"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
+
 [[package]]
 name = "hermit-abi"
 version = "0.2.6"
@@ -374,6 +511,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "home"
+version = "0.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5444c27eef6923071f7ebcc33e3444508466a76f7a2b93da00ed6e19f30c1ddb"
+dependencies = [
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "http"
 version = "0.2.9"
@@ -501,12 +647,46 @@ version = "2.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "12b6ee2129af8d4fb011108c73d99a1b83a85977f23b82460c0ae2e25bb4b57f"
 
+[[package]]
+name = "is-terminal"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adcf93614601c8129ddf72e2d5633df827ba6551541c6d8c59520a371475be1f"
+dependencies = [
+ "hermit-abi 0.3.1",
+ "io-lifetimes",
+ "rustix",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "453ad9f582a441959e5f0d088b02ce04cfe8d51a8eaf077f12ac6d3e94164ca6"
 
+[[package]]
+name = "jni"
+version = "0.21.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a87aa2bb7d2af34197c04845522473242e1aa17c12f4935d5856491a7fb8c97"
+dependencies = [
+ "cesu8",
+ "cfg-if",
+ "combine",
+ "jni-sys",
+ "log",
+ "thiserror",
+ "walkdir",
+ "windows-sys 0.45.0",
+]
+
+[[package]]
+name = "jni-sys"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8eaf4bc02d17cbdd7ff4c7438cafcdf7fb9a4613313ad11b4f8fefe7d3fa0130"
+
 [[package]]
 name = "josekit"
 version = "0.8.3"
@@ -608,6 +788,12 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "ndk-context"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "27b02d87554356db9e9a873add8782d4ea6e3e58ea071a9adb9a2e8ddb884a8b"
+
 [[package]]
 name = "num_cpus"
 version = "1.15.0"
@@ -829,6 +1015,15 @@ version = "1.0.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f91339c0467de62360649f8d3e185ca8de4224ff281f66000de5eb2a77a79041"
 
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "schannel"
 version = "0.1.21"
@@ -945,6 +1140,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
 [[package]]
 name = "syn"
 version = "2.0.22"
@@ -1144,6 +1345,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "utf8parse"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
+
 [[package]]
 name = "vcpkg"
 version = "0.2.15"
@@ -1156,6 +1363,16 @@ version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "walkdir"
+version = "2.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36df944cda56c7d8d8b7496af378e6b16de9284591917d307c9b4d313c44e698"
+dependencies = [
+ "same-file",
+ "winapi-util",
+]
+
 [[package]]
 name = "want"
 version = "0.3.1"
@@ -1263,6 +1480,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
@@ -1284,13 +1510,37 @@ dependencies = [
  "windows_x86_64_msvc 0.42.2",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.45.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75283be5efb2831d37ea142365f009c02ec203cd29a3ebecbc093d52315b66d0"
+dependencies = [
+ "windows-targets 0.42.2",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.48.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "677d2418bec65e3338edb076e806bc1ec15693c5d0104683f2efe857f61056a9"
 dependencies = [
- "windows-targets",
+ "windows-targets 0.48.0",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.42.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e5180c00cd44c9b1c88adb3693291f1cd93605ded80c250a75d472756b4d071"
+dependencies = [
+ "windows_aarch64_gnullvm 0.42.2",
+ "windows_aarch64_msvc 0.42.2",
+ "windows_i686_gnu 0.42.2",
+ "windows_i686_msvc 0.42.2",
+ "windows_x86_64_gnu 0.42.2",
+ "windows_x86_64_gnullvm 0.42.2",
+ "windows_x86_64_msvc 0.42.2",
 ]
 
 [[package]]
@@ -1400,3 +1650,12 @@ checksum = "80d0f4e272c85def139476380b12f9ac60926689dd2e01d4923222f40580869d"
 dependencies = [
  "winapi",
 ]
+
+[[package]]
+name = "xdg"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "688597db5a750e9cad4511cb94729a078e274308099a0382b5b8203bbc767fee"
+dependencies = [
+ "home",
+]
diff --git a/Cargo.toml b/Cargo.toml
index 975974b..4befaa3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,3 +9,9 @@ edition = "2021"
 
 [workspace]
 members = ["crates/*"]
+
+[dependencies]
+anyhow = "1.0.71"
+app_dirs2 = "2.5.5"
+clap = { version = "4.3.9", features = ["derive"] }
+thiserror = "1.0.40"
diff --git a/src/commands/mod.rs b/src/commands/mod.rs
new file mode 100644
index 0000000..8966f37
--- /dev/null
+++ b/src/commands/mod.rs
@@ -0,0 +1,5 @@
+use crate::AspmConfig;
+
+pub trait AspmSubcommand {
+	fn execute(&self, config: AspmConfig) -> u8;
+}
diff --git a/src/main.rs b/src/main.rs
index e0a21f5..ce56817 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,64 @@
+mod commands;
+
+use app_dirs2::{AppDataType, AppInfo};
+use clap::Parser;
+use thiserror::Error;
+
+use std::path::PathBuf;
+
+const APP_INFO: AppInfo = AppInfo {
+	name: env!("CARGO_CRATE_NAME"),
+	author: "Ty",
+};
+
+#[derive(Debug)]
+pub struct AspmConfig {
+	data_dir: PathBuf,
+}
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+struct AspmCommand {
+	/// The directory to use, overriding OS defaults. This can also be set with the ASPM_DATA_DIR environment variable.
+	/// The order of precedence is:
+	/// 1. Command line flag
+	/// 2. Environment variable
+	/// 3. OS default
+	#[arg(short, long, value_name = "FILE")]
+	data_dir: Option<PathBuf>,
+}
+
 fn main() {
-    todo!();
-}
\ No newline at end of file
+	match cli() {
+		Err(e) => eprintln!("An error occurred while running that command:\n{e}"),
+		_ => (),
+	}
+}
+
+fn cli() -> Result<(), AspmError> {
+	let parsed = AspmCommand::parse();
+
+	let config = AspmConfig {
+		data_dir: parsed.data_dir.unwrap_or(
+			std::env::var("ASPM_DATA_DIR").map(|s| s.into()).unwrap_or(
+				app_dirs2::get_app_root(AppDataType::UserData, &APP_INFO)
+					.map_err(|e| AspmError::UnknownError(e.into()))?,
+			),
+		),
+	};
+	// Check the dir (read and write)
+	std::fs::read_dir(&config.data_dir).or(Err(AspmError::DataDirReadError))?;
+	std::fs::create_dir_all(&config.data_dir).or(Err(AspmError::DataDirCreateError))?;
+
+	Ok(())
+}
+
+#[derive(Error, Debug)]
+enum AspmError {
+	#[error("The data directory was unable to be created, is it correct, and does the current user have permission to create it?")]
+	DataDirCreateError,
+	#[error("The data directory was unable to be read, is it correct, and does the current user have permission to read it?")]
+	DataDirReadError,
+	#[error("An unknown internal error occurred, please report this to the developer")]
+	UnknownError(#[source] anyhow::Error),
+}