diff --git a/snag.json b/snag.json
index 42a6ae2..d8f176b 100644
--- a/snag.json
+++ b/snag.json
@@ -2,7 +2,7 @@
 	"git": "/tmp/testgit",
 	"project": "/tmp/test",
 	"email": "user@site.domain",
-	"user": "snag",
+	"author": "snag",
 	"presnag": [
 		"/usr/bin/ls",
 		"/usr/local/bin/script.sh"
diff --git a/source/app.d b/source/app.d
index 97c24ba..7592ee2 100644
--- a/source/app.d
+++ b/source/app.d
@@ -11,14 +11,37 @@ int main(string[] args)
 	auto argumets = new Program(programName, snagVersion)
 		.add(new Command("init", "Initializing the repository for storing snapshots"))
 		.add(new Command("status", "Checking the status of tracked files"))
-		.add(new Command("create", "Create a new backup"))
-		.add(new Command("list", "List of backups")
+		.add(new Command("diff", "Show changed data"))
+		.add(new Command("create", "Create a new snapshot")
+			.add(new Option("c", "comment", "Specify comment")
+				.optional
+				.validateEachWith(
+					opt => opt.length > 0,
+					"cannot be empty"
+				)
+			)
+			.add(new Option("a", "author", "Specify author")
+				.optional
+				.validateEachWith(
+					opt => opt.length > 0,
+					"cannot be empty"
+				)
+			)
+			.add(new Option("e", "email", "Specify email")
+				.optional
+				.validateEachWith(
+					opt => opt.isValidEmail,
+					"must contain an email address"
+				)
+			)
+		)
+		.add(new Command("list", "List of snapshots")
 			.add(new Flag("c", "comment", "Show comment")
 				.name("comment")
 				.optional
 			)
-			.add(new Flag("u", "user", "Show user")
-				.name("user")
+			.add(new Flag("a", "author", "Show author")
+				.name("author")
 				.optional
 			)
 			.add(new Flag("e", "email", "Show email")
@@ -33,7 +56,7 @@ int main(string[] args)
 			.optional
 			.validateEachWith(
 				opt => opt.exists && opt.isFile,
-				"A JSON file path must be provided"
+				"must specify the path to the JSON file"
 			)
 		)
 		.parse(args);
@@ -56,16 +79,23 @@ int main(string[] args)
 			.on("init", init =>
 				snag.initialize()
 			)
+			.on("diff", diff =>
+				snag.diff()
+			)
 			.on("status", status =>
 				snag.status()
 			)
 			.on("create", create =>
-				snag.create()
+				snag.create(
+					create.option("comment", ""),
+					create.option("author", ""),
+					create.option("email", "")
+				)
 			)
 			.on("list", list =>
 				snag.list(
 					list.flag("comment"),
-					list.flag("user"),
+					list.flag("author"),
 					list.flag("email")
 				)
 			)
diff --git a/source/snag/config/config.d b/source/snag/config/config.d
index 2d25f51..75de340 100644
--- a/source/snag/config/config.d
+++ b/source/snag/config/config.d
@@ -3,8 +3,8 @@ module snag.config.config;
 import std.json;
 import std.file;
 import std.path;
-import std.regex;
 import std.string;
+import snag.lib;
 
 import snag.config.exception;
 
@@ -12,12 +12,7 @@ class SnagConfig {
 	private string _git;
 	private string _project;
 	private string _email;
-	private string _user;
-
-	private bool isValidEmail(string email) {
-		auto emailPattern = ctRegex!r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$";
-		return !matchFirst(email, emailPattern).empty;
-	}
+	private string _author;
 
 	this(string configFile) {
 		string jsonText;
@@ -87,21 +82,21 @@ class SnagConfig {
 				~ _email
 			);
 		
-		if ("user" !in jsonData)
+		if ("author" !in jsonData)
 			throw new SnagConfigException(
-				"The configuration file is missing the \"user\" parameter"
+				"The configuration file is missing the \"author\" parameter"
 			);
 
-		_user = jsonData["user"].str;
+		_author = jsonData["author"].str;
 
-		if (!_user.length)
+		if (!_author.length)
 			throw new SnagConfigException(
-				"The \"user\" parameter must contain an user name"
+				"The \"author\" parameter must contain an author name"
 			);
 	}
 
 	@property string git() const { return _git; }
 	@property string project() const { return _project; }
 	@property string email() const { return _email; }
-	@property string user() const { return _user; }
+	@property string author() const { return _author; }
 }
diff --git a/source/snag/core/core.d b/source/snag/core/core.d
index 5aae3ec..828563b 100644
--- a/source/snag/core/core.d
+++ b/source/snag/core/core.d
@@ -8,8 +8,8 @@ import std.array;
 import std.process;
 import std.algorithm;
 import std.string;
-import std.regex;
 
+import snag.lib;
 import snag.core.exception;
 
 class Snag {
@@ -17,11 +17,6 @@ class Snag {
 	private SnagConfig _config;
 	private string _date;
 
-	private bool isValidHash(string hash) {
-		auto hashPattern = ctRegex!r"^[a-fA-F0-9]{7}$";
-		return !matchFirst(hash, hashPattern).empty;
-	}
-
 	this(SnagConfig config) {
 		_baseCommand = format(
 			"git --git-dir=%s --work-tree=%s",
@@ -58,7 +53,7 @@ class Snag {
 			"A Git repository initialization error occurred"
 		);
 		git(
-			["config", "user.name", _config.user],
+			["config", "user.name", _config.author],
 			"A Git repository initialization error occurred"
 		);
 		writeln(
@@ -84,7 +79,7 @@ class Snag {
 		});
 	}
 
-	void create() {
+	void create(string comment, string author, string email) {
 		auto result = git(
 			["status", "--porcelain"],
 			"An error occurred while checking the file tracking status"
@@ -96,11 +91,16 @@ class Snag {
 				"Current file state doesn't need to be archived again"
 			);
 
+		author.length && (environment["GIT_AUTHOR_NAME"] = author);
+		email.length && (environment["GIT_AUTHOR_EMAIL"] = email);
+
+		string message = comment.length ? comment : "Standard snapshot creation";
+
 		result = execute(_baseCommand ~ ["rev-parse", "--short", "HEAD"]);
 		if (result.status == 128) {
 			// Если это самый первый коммит после инициализации репозитория
 			git(["add", "."], "Failed to prepare files for archiving");
-			git(["commit", "-m", "test"], "Failed to create a backup");
+			git(["commit", "-m"] ~ message, "Failed to create a backup");
 			writeln("Backup was created successfully");
 			return;
 		} else if (result.status != 0)
@@ -139,7 +139,7 @@ class Snag {
 				"Failed to prepare files for archiving"
 			);
 			git(
-				["commit", "-m", "test"],
+				["commit", "-m"] ~ message,
 				"Failed to create a backup"
 			);
 			newSnapshot = git(
@@ -153,7 +153,7 @@ class Snag {
 				"Failed to prepare files for archiving"
 			);
 			git(
-				["commit", "-m", "test"],
+				["commit", "-m"] ~ message,
 				"Failed to create a backup"
 			);
 			newSnapshot = git(
@@ -172,7 +172,7 @@ class Snag {
 		writeln("Backup was created successfully: ", newSnapshot);
 	}
 
-	void list(bool comment, bool user, bool email) {
+	void list(bool comment, bool author, bool email) {
 		string currentSnapshot = git(
 			["rev-parse", "--short", "HEAD"],
 			"Failed to retrieve current snapshot information"
@@ -181,7 +181,7 @@ class Snag {
 		string format = "format:%h\t%ad";
 
 		comment && (format ~= "\t%s");
-		user && (format ~= "\t%an");
+		author && (format ~= "\t%an");
 		email && (format ~= "\t%ae");
 
 		git(
@@ -193,7 +193,7 @@ class Snag {
 			],
 			"Failed to retrieve the list of snapshots"
 		).output.split('\n').map!(line => line.split('\t')).array.each!(e =>
-        	writefln("%s\t%s",
+			writefln("%s\t%s",
 				currentSnapshot == e[0] ? "    >" : "",
 				e.join("\t")
 			)
@@ -227,4 +227,16 @@ class Snag {
 		);
 		writeln("Backup was restored successfully: ", hash);
 	}
+
+	void diff() {
+		auto result = git(
+			["diff"],
+			"Failed to retrieve changes"
+		);
+		if (result.output.length) {
+			result.output.write;
+			return;
+		}
+		writeln("No changes at the moment");
+	}
 }
diff --git a/source/snag/lib/lib.d b/source/snag/lib/lib.d
new file mode 100644
index 0000000..3277d0e
--- /dev/null
+++ b/source/snag/lib/lib.d
@@ -0,0 +1,13 @@
+module snag.lib.lib;
+
+import std.regex;
+
+bool isValidHash(string hash) {
+	auto hashPattern = ctRegex!r"^[a-fA-F0-9]{7}$";
+	return !matchFirst(hash, hashPattern).empty;
+}
+
+bool isValidEmail(string email) {
+	auto emailPattern = ctRegex!r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$";
+	return !matchFirst(email, emailPattern).empty;
+}
diff --git a/source/snag/lib/package.d b/source/snag/lib/package.d
new file mode 100644
index 0000000..46fa21c
--- /dev/null
+++ b/source/snag/lib/package.d
@@ -0,0 +1,3 @@
+module snag.lib;
+
+public import snag.lib.lib;
diff --git a/source/snag/package.d b/source/snag/package.d
index 22b28bf..ae8b15d 100644
--- a/source/snag/package.d
+++ b/source/snag/package.d
@@ -1,5 +1,6 @@
 module snag;
 
 public import snag.version_;
+public import snag.lib;
 public import snag.config;
 public import snag.core;
diff --git a/source/snag/version_.d b/source/snag/version_.d
index 2bdebb8..0c40657 100644
--- a/source/snag/version_.d
+++ b/source/snag/version_.d
@@ -1,3 +1,3 @@
 module snag.version_;
 
-enum snagVersion = "0.0.7";
+enum snagVersion = "0.0.8";