diff --git a/src/cli.rs b/src/cli.rs
index b451f7a..5d7b628 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -1,5 +1,11 @@
+use std::error::Error;
+
 use clap::{Args, Parser, Subcommand};
 
+use crate::config;
+use crate::config::Profile;
+use crate::git;
+
 #[derive(Debug, Parser)]
 #[command(version, about = "a cli to change git users")]
 pub struct Cli {
@@ -9,13 +15,47 @@ pub struct Cli {
 
 #[derive(Debug, Subcommand)]
 pub enum Commands {
-    List,
+    List(ListArgs),
     Use(UseArgs),
     Add(AddArgs),
     Remove(RemoveArgs),
     Current(CurrentArgs),
 }
 
+impl Commands {
+    pub fn execute(self) -> Result<(), Box<dyn Error>> {
+        match self {
+            Commands::List(args) => args.execute(),
+            Commands::Use(args) => args.execute(),
+            Commands::Add(args) => args.execute(),
+            Commands::Remove(args) => args.execute(),
+            Commands::Current(args) => args.execute(),
+        }
+    }
+}
+
+#[derive(Debug, Args)]
+pub struct ListArgs;
+
+impl ListArgs {
+    fn execute(self) -> Result<(), Box<dyn Error>> {
+        let profiles = config::get_profile_list()?;
+        if profiles.is_empty() {
+            println!("no profiles found");
+            return Ok(());
+        }
+
+        println!("{:<15} {:<20} {:<25}", "profile", "name", "email");
+        for profile in profiles {
+            println!(
+                "{:<15} {:<20} {:<25}",
+                profile.name, profile.username, profile.email
+            );
+        }
+        Ok(())
+    }
+}
+
 #[derive(Debug, Args)]
 pub struct UseArgs {
     pub profile_name: String,
@@ -23,6 +63,23 @@ pub struct UseArgs {
     pub global: bool,
 }
 
+impl UseArgs {
+    fn execute(self) -> Result<(), Box<dyn Error>> {
+        let profiles = config::get_profile_list()?;
+        let profile = profiles.iter().find(|p| p.name == self.profile_name);
+        if profile.is_none() {
+            println!("profile not found");
+            return Ok(());
+        }
+
+        let profile = profile.unwrap();
+
+        git::set_git_config("user.name", &profile.username, self.global)?;
+        git::set_git_config("user.email", &profile.email, self.global)?;
+        Ok(())
+    }
+}
+
 #[derive(Debug, Args)]
 pub struct AddArgs {
     pub profile_name: String,
@@ -32,13 +89,55 @@ pub struct AddArgs {
     pub email: String,
 }
 
+impl AddArgs {
+    fn execute(self) -> Result<(), Box<dyn Error>> {
+        let mut profiles = config::get_profile_list()?;
+        let existing_profile = profiles.iter().position(|p| p.name == self.profile_name);
+        if existing_profile.is_some() {
+            println!("profile already exists");
+            return Ok(());
+        }
+        profiles.push(Profile {
+            name: self.profile_name,
+            username: self.name,
+            email: self.email,
+        });
+        config::write_profile_list(profiles)?;
+        println!("profile added");
+        Ok(())
+    }
+}
+
 #[derive(Debug, Args)]
 pub struct RemoveArgs {
     pub profile_name: String,
 }
 
+impl RemoveArgs {
+    fn execute(self) -> Result<(), Box<dyn Error>> {
+        let mut profiles = config::get_profile_list()?;
+        let index = profiles
+            .iter()
+            .position(|p| p.name == self.profile_name)
+            .expect("unable to find profile");
+        profiles.remove(index);
+        config::write_profile_list(profiles)?;
+        println!("profile removed");
+        Ok(())
+    }
+}
+
 #[derive(Debug, Args)]
 pub struct CurrentArgs {
     #[arg(short, long)]
     pub global: bool,
 }
+
+impl CurrentArgs {
+    fn execute(self) -> Result<(), Box<dyn Error>> {
+        let name = git::get_git_config("user.name", self.global)?;
+        let email = git::get_git_config("user.email", self.global)?;
+        println!("current user: {} ({})", name, email);
+        Ok(())
+    }
+}
diff --git a/src/config.rs b/src/config.rs
index 98af736..7229606 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,6 +1,7 @@
 use std::{
+    error::Error,
     fs::{self, File},
-    io::{BufReader, BufWriter, Error},
+    io::{BufReader, BufWriter},
     path::{Path, PathBuf},
 };
 
@@ -13,39 +14,36 @@ pub struct Profile {
     pub email: String,
 }
 
-fn get_config_dir() -> PathBuf {
-    let mut config_dir = dirs::config_dir().expect("unable to find config dir");
+fn get_config_dir() -> Result<PathBuf, Box<dyn Error>> {
+    let mut config_dir = dirs::config_dir().ok_or("unable to get config dir")?;
     config_dir.push("git-su");
-    config_dir
+    Ok(config_dir)
 }
 
-fn create_if_missing(file: &Path, content: &str) -> Result<(), Error> {
+fn create_if_missing(file: &Path, content: &str) -> Result<(), Box<dyn Error + 'static>> {
     if !file.exists() {
-        fs::write(file, content)
-    } else {
-        Ok(())
+        fs::write(file, content)?;
     }
-}
-
-pub fn get_profile_list() -> Result<Vec<Profile>, String> {
-    let config_dir = get_config_dir();
-    fs::create_dir_all(&config_dir).expect("unable to create config directory");
-    let profile_file = config_dir.join("profiles.json");
-    create_if_missing(profile_file.as_path(), "[]").expect("unable to create profile file");
-    let profile_file = File::open(&profile_file).expect("unable to open profile file");
-    let reader = BufReader::new(profile_file);
-    Ok(
-        serde_json::from_reader::<BufReader<File>, Vec<Profile>>(reader)
-            .expect("unable to parse json"),
-    )
-}
-
-pub fn write_profile_list(profiles: Vec<Profile>) -> Result<(), String> {
-    let config_dir = get_config_dir();
-    fs::create_dir_all(&config_dir).expect("unable to create config directory");
-    let profile_file = config_dir.join("profiles.json");
-    let profile_file = File::create(&profile_file).expect("unable to create profile file");
-    let writer = BufWriter::new(profile_file);
-    serde_json::to_writer_pretty(writer, &profiles).expect("unable to write json");
+    Ok(())
+}
+
+pub fn get_profile_list() -> Result<Vec<Profile>, Box<dyn Error>> {
+    let config_dir = get_config_dir()?;
+    fs::create_dir_all(&config_dir)?;
+    let profile_file = config_dir.join("profiles.json");
+    create_if_missing(profile_file.as_path(), "[]")?;
+    let profile_file = File::open(&profile_file)?;
+    let reader = BufReader::new(profile_file);
+    let profiles = serde_json::from_reader::<BufReader<File>, Vec<Profile>>(reader)?;
+    Ok(profiles)
+}
+
+pub fn write_profile_list(profiles: Vec<Profile>) -> Result<(), Box<dyn Error>> {
+    let config_dir = get_config_dir()?;
+    fs::create_dir_all(&config_dir)?;
+    let profile_file = config_dir.join("profiles.json");
+    let profile_file = File::create(&profile_file)?;
+    let writer = BufWriter::new(profile_file);
+    serde_json::to_writer_pretty(writer, &profiles)?;
     Ok(())
 }
diff --git a/src/git.rs b/src/git.rs
new file mode 100644
index 0000000..c79d68f
--- /dev/null
+++ b/src/git.rs
@@ -0,0 +1,35 @@
+use std::{error::Error, process::Command};
+
+pub fn get_git_config(key: &str, global: bool) -> Result<String, Box<dyn Error>> {
+    let args = if global {
+        vec!["config", "--global", key]
+    } else {
+        vec!["config", key]
+    };
+
+    let result = run_command("git", &args)?;
+    Ok(result.trim().to_string())
+}
+
+pub fn set_git_config(key: &str, value: &str, global: bool) -> Result<(), Box<dyn Error>> {
+    let args = if global {
+        vec!["config", "--global", key, value]
+    } else {
+        vec!["config", key, value]
+    };
+
+    let _ = run_command("git", &args)?;
+    Ok(())
+}
+
+fn run_command(command: &str, args: &[&str]) -> Result<String, Box<dyn Error>> {
+    let child = Command::new(command).args(args).output()?;
+
+    if child.status.success() {
+        let stdout = String::from_utf8(child.stdout)?;
+        Ok(stdout.to_owned())
+    } else {
+        let stderr = String::from_utf8(child.stderr)?;
+        Ok(stderr.to_owned())
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 9c2314e..f418d2f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,99 +1,14 @@
 use clap::Parser;
 
-use crate::cli::Commands;
-use crate::config::Profile;
-
 mod cli;
 mod config;
-mod utils;
+mod git;
 
 fn main() {
     let args = cli::Cli::parse();
 
-    match args.command {
-        Commands::List => {
-            let profiles = config::get_profile_list().expect("unable to get list of profiles");
-            if profiles.is_empty() {
-                println!("no profiles found");
-                return;
-            }
-
-            println!("{:<15} {:<20} {:<25}", "profile", "name", "email");
-            for profile in profiles {
-                println!(
-                    "{:<15} {:<20} {:<25}",
-                    profile.name, profile.username, profile.email
-                );
-            }
-        }
-        Commands::Use(args) => {
-            let profiles = config::get_profile_list().expect("unable to get list of profiles");
-            let profile = profiles.iter().find(|p| p.name == args.profile_name);
-            if profile.is_none() {
-                println!("profile not found");
-                return;
-            }
-
-            let profile = profile.unwrap();
-
-            utils::run_command(
-                "git",
-                &add_global_if(&["config", "user.name", &profile.username], args.global),
-            )
-            .expect("command failed");
-            utils::run_command(
-                "git",
-                &add_global_if(&["config", "user.email", &profile.email], args.global),
-            )
-            .expect("command failed");
-        }
-        Commands::Add(args) => {
-            let mut profiles = config::get_profile_list().expect("unable to get list of profiles");
-            let existing_profile = profiles.iter().position(|p| p.name == args.profile_name);
-            if existing_profile.is_some() {
-                println!("profile already exists");
-                return;
-            }
-            profiles.push(Profile {
-                name: args.profile_name,
-                username: args.name,
-                email: args.email,
-            });
-            config::write_profile_list(profiles).expect("unable to write profile file");
-            println!("profile added")
-        }
-        Commands::Remove(args) => {
-            let mut profiles = config::get_profile_list().expect("unable to get list of profiles");
-            let index = profiles
-                .iter()
-                .position(|p| p.name == args.profile_name)
-                .expect("unable to find profile");
-            profiles.remove(index);
-            config::write_profile_list(profiles).expect("unable to write profile file");
-            println!("profile removed")
-        }
-        Commands::Current(args) => {
-            let mut name =
-                utils::run_command("git", &add_global_if(&["config", "user.name"], args.global))
-                    .expect("command failed");
-            let mut email = utils::run_command(
-                "git",
-                &add_global_if(&["config", "user.email"], args.global),
-            )
-            .expect("command failed");
-
-            name.pop();
-            email.pop();
-
-            println!("current user: {} ({})", name, email);
-        }
+    if let Err(why) = args.command.execute() {
+        eprintln!("error: {}", why);
+        std::process::exit(1);
     }
 }
-
-fn add_global_if<'a>(args: &[&'a str], global: bool) -> Vec<&'a str> {
-    let mut result = args.to_vec();
-    if global {
-        result.insert(1, "--global");
-    }
-    result
-}
diff --git a/src/utils.rs b/src/utils.rs
deleted file mode 100644
index 2742826..0000000
--- a/src/utils.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-use std::process::Command;
-
-pub fn run_command(command: &str, args: &[&str]) -> Result<String, String> {
-    let child = Command::new(command)
-        .args(args)
-        .output()
-        .expect("failed to execute process");
-
-    if child.status.success() {
-        let stdout = String::from_utf8(child.stdout).unwrap();
-        Ok(stdout.to_owned())
-    } else {
-        let stderr = String::from_utf8(child.stderr).unwrap();
-        Err(stderr)
-    }
-}