diff --git a/src/extension/mod.rs b/src/extension/mod.rs
index e90f62b..139dea2 100644
--- a/src/extension/mod.rs
+++ b/src/extension/mod.rs
@@ -1,6 +1,7 @@
 use serde_yaml::Mapping;
 
 mod date;
+mod shell;
 
 pub trait Extension {
     fn name(&self) -> String;
@@ -10,5 +11,6 @@ pub trait Extension {
 pub fn get_extensions() -> Vec<Box<dyn Extension>> {
     vec![
         Box::new(date::DateExtension::new()),
+        Box::new(shell::ShellExtension::new()),
     ]
 }
\ No newline at end of file
diff --git a/src/extension/shell.rs b/src/extension/shell.rs
new file mode 100644
index 0000000..6b54b81
--- /dev/null
+++ b/src/extension/shell.rs
@@ -0,0 +1,49 @@
+use serde_yaml::{Mapping, Value};
+use std::process::Command;
+use log::{warn, error};
+
+pub struct ShellExtension {}
+
+impl ShellExtension {
+    pub fn new() -> ShellExtension {
+        ShellExtension{}
+    }
+}
+
+impl super::Extension for ShellExtension {
+    fn name(&self) -> String {
+        String::from("shell")
+    }
+
+    fn calculate(&self, params: &Mapping) -> Option<String> {
+        let cmd = params.get(&Value::from("cmd"));
+        if cmd.is_none() {
+            warn!("No 'cmd' parameter specified for shell variable");
+            return None
+        }
+        let cmd = cmd.unwrap().as_str().unwrap();
+
+        let output = if cfg!(target_os = "windows") {
+            Command::new("cmd")
+                .args(&["/C", cmd])
+                .output()
+        } else {
+            Command::new("sh")
+                .arg("-c")
+                .arg(cmd)
+                .output()
+        };
+
+        match output {
+            Ok(output) => {
+                let output_str = String::from_utf8_lossy(output.stdout.as_slice());
+
+                Some(output_str.into_owned())
+            },
+            Err(e) => {
+                error!("Could not execute cmd '{}', error: {}", cmd, e);
+                None
+            },
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/res/config.yaml b/src/res/config.yaml
index 2e5676f..906bbd9 100644
--- a/src/res/config.yaml
+++ b/src/res/config.yaml
@@ -23,7 +23,7 @@ matches:
   # Accented letters
   - trigger: "e'"
     replace: "è"
-  - trigger: "e/"
+  - trigger: "e//"
     replace: "é"
   - trigger: "a'"
     replace: "à"