diff --git a/src/tcl.rs b/src/tcl.rs
new file mode 100644
index 0000000..71d97fe
--- /dev/null
+++ b/src/tcl.rs
@@ -0,0 +1,34 @@
+// @name commands
+// @return Vec<String>
+// @brief Extract commands by semicolon and newline
+// @param tcl: &str
+pub fn commands(tcl: &str) -> Vec<String> {
+    let mut commands: Vec<String> = vec![];
+    let mut quote: bool = false;
+    let mut new_command: String = String::new();
+
+    for character in tcl.chars() {
+        if quote {
+            new_command.push(character);
+            if character == '"' {
+                quote = false;
+            }
+        } else {
+            match character {
+                '\n' | ';' => {
+                    commands.push(new_command.clone());
+                    new_command = String::new();
+                }
+                '"' => {
+                    new_command.push(character);
+                    quote = true;
+                }
+                _ => new_command.push(character),
+            }
+        }
+    }
+
+    commands.push(new_command);
+
+    return commands;
+}