diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index c39e374..955a7de 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -6,6 +6,7 @@ image: "rust:latest"
 variables:
   CARGO_HOME: $CI_PROJECT_DIR/.cargo
   PACKAGE_REGISTRY_URL: "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/generic/fif"
+  RUSTFLAGS: "-C debuginfo=0"
 
 cache:
   paths:
@@ -37,7 +38,7 @@ stages:
   script:
     - cargo install cargo-sweep
     - cargo sweep -i
-    - git -C $CI_PROJECT_DIR/.cargo/registry/index/github.com-1ecc6299db9ec823/ gc || true
+    - git -C $CI_PROJECT_DIR/.cargo/registry/index/github.com-1ecc6299db9ec823/ gc --aggressive || true
 
 # this builds a "base" version of fif with default features enabled. this is done separately from the main build step
 # for the purposes of caching - by building once *before* executing the parallel cargo-build step, we ensure that
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8385131..9cf868e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,10 +7,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ## Unreleased
 ### Changed
 - Updated [`new_mime_guess`] to 4.0.0
+- `--version` output now handles missing Git commit hashes, and specifies the target operating system
 ### Fixed
 - Disabled [`smartstring`] test on unsupported architectures
 ### Other
 - Use [`parking_lot`]'s `RwLock` instead of the built-in one for a slight performance increase
+- Added more command line argument tests
 
 ## v0.4.0 - 2021-10-14
 ### Added
diff --git a/Cargo.lock b/Cargo.lock
index 9bd0eae..c24cf83 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,12 +2,35 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "aho-corasick"
+version = "0.7.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e37cfd5e7657ada45f742d6e99ca5788580b5c529dc78faf11ece6dc702656f"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "arrayvec"
 version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "23b62fc65de8e4e7f52534fb52b0f3ed04746ae267519eef2a83941e8085068b"
 
+[[package]]
+name = "assert_cmd"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e996dc7940838b7ef1096b882e29ec30a3149a3a443cdc8dba19ed382eca1fe2"
+dependencies = [
+ "bstr",
+ "doc-comment",
+ "predicates",
+ "predicates-core",
+ "predicates-tree",
+ "wait-timeout",
+]
+
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -31,6 +54,17 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "bstr"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ba3569f383e8f1598449f1a423e72e99569137b47740b1da11ef19af3d5c3223"
+dependencies = [
+ "lazy_static",
+ "memchr",
+ "regex-automata",
+]
+
 [[package]]
 name = "byteorder"
 version = "1.4.3"
@@ -129,6 +163,12 @@ dependencies = [
  "lazy_static",
 ]
 
+[[package]]
+name = "difflib"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6184e33543162437515c2e2b48714794e37845ec9851711914eec9d308f6ebe8"
+
 [[package]]
 name = "dirs-next"
 version = "2.0.0"
@@ -150,6 +190,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "doc-comment"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fea41bba32d969b513997752735605054bc0dfa92b4c56bf1189f2e174be7a10"
+
 [[package]]
 name = "either"
 version = "1.6.1"
@@ -177,6 +223,7 @@ checksum = "de853764b47027c2e862a995c34978ffa63c1501f2e15f987ba11bd4f9bba193"
 name = "fif"
 version = "0.4.0"
 dependencies = [
+ "assert_cmd",
  "cfg-if",
  "clap",
  "clap_derive",
@@ -193,6 +240,7 @@ dependencies = [
  "parking_lot",
  "rand",
  "rayon",
+ "regex",
  "serde",
  "serde_json",
  "smartstring",
@@ -471,6 +519,33 @@ version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
 
+[[package]]
+name = "predicates"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95e5a7689e456ab905c22c2b48225bb921aba7c8dfa58440d68ba13f6222a715"
+dependencies = [
+ "difflib",
+ "itertools",
+ "predicates-core",
+]
+
+[[package]]
+name = "predicates-core"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57e35a3326b75e49aa85f5dc6ec15b41108cf5aee58eabb1f274dd18b73c2451"
+
+[[package]]
+name = "predicates-tree"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "338c7be2905b732ae3984a2f40032b5e94fd8f52505b186c7d4d68d193445df7"
+dependencies = [
+ "predicates-core",
+ "termtree",
+]
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -597,6 +672,29 @@ dependencies = [
  "redox_syscall",
 ]
 
+[[package]]
+name = "regex"
+version = "1.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d07a8629359eb56f1e2fb1652bb04212c072a87ba68546a04065d525673ac461"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
+
+[[package]]
+name = "regex-syntax"
+version = "0.6.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
+
 [[package]]
 name = "remove_dir_all"
 version = "0.5.3"
@@ -739,6 +837,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "termtree"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13a4ec180a2de59b57434704ccfad967f789b12737738798fa08798cd5824c16"
+
 [[package]]
 name = "textwrap"
 version = "0.12.1"
@@ -820,6 +924,15 @@ version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "wait-timeout"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f200f5b12eb75f8c1ed65abd4b2db8a6e1b138a20de009dacee265a2498f3f6"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "walkdir"
 version = "2.3.2"
diff --git a/Cargo.toml b/Cargo.toml
index 2ba2e3b..a155ca1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -78,6 +78,8 @@ features = ["termcolor", "atty"]
 [dev-dependencies]
 tempfile = "3.2.0"
 rand = "0.8.3"
+assert_cmd = "2.0.2"
+regex = "1.5.4"
 
 [profile.release]
 lto = "thin"
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
index 3b77b09..5e624e8 100644
--- a/src/tests/mod.rs
+++ b/src/tests/mod.rs
@@ -294,6 +294,7 @@ fn exclude_set_overrides_include_set() {
 #[test]
 /// Ensure that badly formed command line arguments are rejected.
 fn rejects_bad_args() {
+	use assert_cmd::Command;
 	let tests = [
 		// Non-existent flags:
 		vec!["fif", "-abcdefghijklmnopqrstuvwxyz"],
@@ -314,10 +315,67 @@ fn rejects_bad_args() {
 	];
 
 	for test in &tests {
+		// first, try testing the flags against the Parameters struct...
 		assert!(Parameters::try_parse_from(test).is_err(), "Failed to reject {:?}", test);
+		// ...then, make sure it actually works against the binary
+		let mut cmd = Command::cargo_bin("fif").unwrap();
+		cmd.args(test).assert().failure();
 	}
 }
 
+#[test]
+/// Ensure that a few simple, well-formed command line argument cases pass
+fn accepts_good_args() {
+	use assert_cmd::Command;
+
+	// all of these commands pass either the version or help flag, ensuring that they won't fail for reasons relating
+	// to filesystem access
+	let tests = [
+		vec!["-V"],
+		vec!["--version"],
+		vec!["-E", "images", "--version"],
+		vec!["-h"],
+		vec!["--help"],
+		vec!["dir_name", "--version"],
+	];
+
+	for test in &tests {
+		let mut cmd = Command::cargo_bin("fif").unwrap();
+		cmd.args(test).assert().success();
+	}
+}
+
+#[test]
+/// Ensures that output from the `-V` and `--version` flags is formatted properly.
+fn check_version_output() {
+	use std::string::String;
+	use assert_cmd::Command;
+	use regex::Regex;
+
+	// test `-V` matches the format of "fif x.y.z"
+	let mut cmd = Command::cargo_bin("fif").unwrap();
+	let output = cmd.arg("-V").ok().unwrap().stdout;
+	let output = String::from_utf8(output).unwrap();
+	assert!(
+		Regex::new(r#"fif v(\d\.){2}\d"#).unwrap().is_match(&output.trim()),
+		"\"{}\" does not match the expected `-v` format!",
+		output
+	);
+
+
+	// test `--version` matches the format of "fif x.y.z (OS, example backend, commit #1234abc)"
+	let mut cmd = Command::cargo_bin("fif").unwrap();
+	let output = cmd.arg("--version").ok().unwrap().stdout;
+	let output = String::from_utf8(output).unwrap();
+	assert!(
+		Regex::new(r#"fif v(\d\.){2}\d \(.+, .+ backend, (unknown commit|commit #[\da-f]{7})\)"#)
+			.unwrap()
+			.is_match(&output.trim()),
+		"\"{}\" does not match the expected `--version` format!",
+		output.trim()
+	);
+}
+
 #[test]
 /// Generate random series of bytes and try to identify them. This test makes no assertions and can only fail if the
 /// mime database somehow panics or hangs.
diff --git a/src/utils.rs b/src/utils.rs
index 51ad095..4477889 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -36,7 +36,7 @@ pub static CLAP_LONG_VERSION: Lazy<String> = Lazy::new(|| {
 		_ => String::from("unknown commit"),
 	};
 
-	format!("v{} ({} backend, {})", VERSION.unwrap_or("???"), BACKEND, commit).into()
+	format!("v{} ({}, {} backend, {})", VERSION.unwrap_or("???"), os_name(), BACKEND, commit).into()
 });
 
 /// A [`Mime`] representing the "application/zip" MIME type.