diff --git a/src/cli.rs b/src/cli.rs
index 30c18b9..9cefa8c 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -6,6 +6,9 @@ use std::path::PathBuf;
 #[clap(author, version, about, long_about = None)]
 pub struct Cli {
     #[clap(value_parser)]
-    pub map_file: PathBuf,
+    pub map_file: Option<PathBuf>,
+    /// List devices and exit
+    #[clap(long, short, action)]
+    pub list: bool,
 }
 
diff --git a/src/config/device.rs b/src/config/device.rs
index b9ee9e0..965dc5e 100644
--- a/src/config/device.rs
+++ b/src/config/device.rs
@@ -55,17 +55,14 @@ impl TryFrom<DeviceConfigSerializer> for DeviceConfig {
     fn try_from(v: DeviceConfigSerializer) -> Result<Self, Self::Error> {
         Ok(DeviceConfig {
             identifier: {
-                if v.name.is_some() {
-                    Identifier::Name(v.name.unwrap())
-                }
-                else if v.regex.is_some() {
-                    Identifier::Regex(regex::Regex::new(&v.regex.unwrap())?)
-                }
-                else if v.addr.is_some() {
-                    Identifier::Addr(v.addr.unwrap())
-                }
-                else {
-                    Identifier::All
+                match (v.name, v.regex, v.addr) {
+                    (Some(_), Some(_), _      ) => return Err(Error::IncompatibleArgs("name","regex")),
+                    (Some(_), None   , Some(_)) => return Err(Error::IncompatibleArgs("name","addr")),
+                    (None   , Some(_), Some(_)) => return Err(Error::IncompatibleArgs("regex","addr")),
+                    (Some(n), None,    None   ) => Identifier::Name(n),
+                    (None,    Some(r), None   ) => Identifier::Regex(regex::Regex::new(&r)?),
+                    (None,    None   , Some(a)) => Identifier::Addr(a),
+                    (None,    None,    None   ) => Identifier::All,
                 }
             },
             max_connections: v.max_connections,
diff --git a/src/error.rs b/src/error.rs
index c1d5c75..861a4d1 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -31,6 +31,10 @@ pub enum Error {
     RemapTooBig(f64),
     #[error("remap value is too low. Minimum value is {}", i64::MIN)]
     RemapTooLow(f64),
+    #[error("'{0}' and '{1}' are incompatible")]
+    IncompatibleArgs(&'static str, &'static str),
+    #[error("no map file was provided")]
+    NoArgument,
     #[error("pipe error")]
     Pipe,
     #[error("unknown error")]
diff --git a/src/main.rs b/src/main.rs
index 4650771..360867d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,13 +21,29 @@ use cli::Cli;
 
 fn main() {
     let c = Cli::parse();
+    if c.list {
+        err_handle(run::list_devices());
+        return;
+    }
+    let map_file = err_handle(
+        c.map_file.ok_or(Error::NoArgument)
+    );
     loop {
-        match run_file(&c.map_file) {
-            Ok(_) => (),
-            Err(err) => {
-                eprintln!("Error: {}", err);
-                std::process::exit(1);
-            }
+        err_handle(
+            run_file(&map_file)
+        );
+    }
+}
+
+fn err_handle<T,E>(r: Result<T, E>) -> T
+where
+    E: std::fmt::Display
+{
+    match r {
+        Ok(v) => v,
+        Err(err) => {
+            eprintln!("Error: {}", err);
+            std::process::exit(1);
         }
     }
 }
diff --git a/src/midi/mod.rs b/src/midi/mod.rs
index 6e00571..9326a9e 100644
--- a/src/midi/mod.rs
+++ b/src/midi/mod.rs
@@ -45,6 +45,15 @@ pub enum MidiPortHandler {
     ALSA(MidiPort<alsa::DeviceAddr>),
 }
 
+impl std::fmt::Display for MidiPortHandler {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            MidiPortHandler::ALSA(p) => write!(f, "{} {}:{}", p.name, p.addr.client, p.addr.port),
+            _ => todo!(),
+        }
+    }
+}
+
 pub enum MidiHandler {
     ALSA(MidiInputAlsa),
 }
diff --git a/src/run.rs b/src/run.rs
index cdb3dc4..c0b3621 100644
--- a/src/run.rs
+++ b/src/run.rs
@@ -24,6 +24,15 @@ pub fn cross_shell(cmd: &str) -> Vec<String> {
     ).collect()
 }
 
+pub fn list_devices() -> Result<(), Error> {
+    let input = MidiHandler::new("rmidimap")?;
+    let ports = input.ports()?;
+    for p in ports {
+        println!("{}", p);
+    }
+    Ok(())
+}
+
 pub fn run_config(conf: &Config) -> Result<(), Error> {
     let cfevmap: Vec<DeviceRunItem> = conf.devices.iter().map(|x|
         (x, EventMap::from(x),