diff --git a/src/main.rs b/src/main.rs
index 5ee91bd..7346551 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,7 +22,10 @@ fn main() -> Result<()> {
         }
 
         let mut tokenizer = Tokenizer::new(PathBuf::from(&path))?;
-        println!("{:?}", tokenizer.tokenize()?);
+        let tokens = tokenizer.tokenize()?;
+        for token in &tokens {
+            println!("{}: {:?}", token.error_prefix(&path), token);
+        }
         return Ok(());
     }
 
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index 12e189c..158f492 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -4,12 +4,25 @@ use anyhow::Result;
 
 use crate::reader::{CharReader, CharType};
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub enum Token {
-    Text(String),
-    CommentMark,
-    HelpMark,
-    EqualSign,
+    Text(usize, usize, String),
+    CommentMark(usize, usize),
+    HelpMark(usize, usize),
+    EqualSign(usize, usize),
+}
+
+impl Token {
+    pub fn error_prefix(&self, path: &String) -> String {
+        let (line, column) = match self {
+            Token::Text(x, y, _) => (x, y),
+            Token::CommentMark(x, y) => (x, y),
+            Token::HelpMark(x, y) => (x, y),
+            Token::EqualSign(x, y) => (x, y),
+        };
+
+        format!("{path}:{line}:{column}")
+    }
 }
 
 pub struct Tokenizer {
@@ -23,6 +36,30 @@ impl Tokenizer {
         })
     }
 
+    fn text(&self, buffer: String, eol: bool, prepends_help: bool) -> Token {
+        let adjust = match (eol, prepends_help) {
+            (true, false) => -1,
+            (false, true) => 2,
+            _ => 0,
+        } + (buffer.len() as i8);
+
+        Token::Text(
+            self.reader.line,
+            self.reader.column - (adjust as usize),
+            buffer.trim().to_string(),
+        )
+    }
+
+    fn equal_sign(&self) -> Token {
+        Token::EqualSign(self.reader.line, self.reader.column)
+    }
+    fn comment_mark(&self) -> Token {
+        Token::CommentMark(self.reader.line, self.reader.column)
+    }
+    fn help_mark(&self) -> Token {
+        Token::HelpMark(self.reader.line, self.reader.column - 2)
+    }
+
     fn next_tokens(&mut self) -> Result<Vec<Token>> {
         let mut buffer = "".to_string();
         loop {
@@ -33,23 +70,27 @@ impl Tokenizer {
                     if buffer.is_empty() {
                         continue;
                     }
-                    return Ok(vec![Token::Text(buffer.trim().to_string())]);
+                    return Ok(vec![self.text(buffer, true, false)]);
                 }
                 CharType::Char(c) => {
                     let mut token: Option<Token> = None;
+                    let mut prepends_help = false;
                     if c == '=' {
-                        token = Some(Token::EqualSign);
-                    } else if c == '#' && self.reader.column == 1 {
-                        token = Some(Token::CommentMark);
-                    } else if c == ' ' && buffer.ends_with("  #") {
-                        buffer = buffer.strip_suffix("  #").unwrap_or("").to_string();
-                        token = Some(Token::HelpMark);
+                        token = Some(self.equal_sign());
+                    } else if c == '#' {
+                        if self.reader.column == 1 {
+                            token = Some(self.comment_mark());
+                        } else if buffer.ends_with("  ") {
+                            buffer = buffer.strip_suffix("  ").unwrap_or("").to_string();
+                            prepends_help = true;
+                            token = Some(self.help_mark());
+                        }
                     }
                     if let Some(t) = token {
                         if buffer.is_empty() {
                             return Ok(vec![t]);
                         }
-                        return Ok(vec![Token::Text(buffer.trim().to_string()), t]);
+                        return Ok(vec![self.text(buffer, false, prepends_help), t]);
                     }
                     buffer.push(c)
                 }
@@ -70,3 +111,64 @@ impl Tokenizer {
         Ok(tokens)
     }
 }
+
+// TODO: move to tests/ as integration test?
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_tokenizer() {
+        let sample = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(".env.sample");
+        let mut tokenizer = Tokenizer::new(sample).unwrap();
+        let tokens = tokenizer.tokenize().unwrap();
+        assert_eq!(tokens.len(), 19);
+
+        // line 1
+        assert_eq!(tokens[0], Token::CommentMark(1, 1));
+        assert_eq!(tokens[1], Token::Text(1, 2, "Createnv".to_string()));
+        assert_eq!(tokens[2], Token::CommentMark(2, 1));
+
+        // line 2
+        assert_eq!(
+            tokens[3],
+            Token::Text(
+                2,
+                2,
+                "This is a simple example of how Createnv works".to_string()
+            )
+        );
+
+        // line 3
+        assert_eq!(tokens[4], Token::Text(3, 1, "NAME".to_string()));
+        assert_eq!(tokens[5], Token::EqualSign(3, 5));
+        assert_eq!(tokens[6], Token::HelpMark(3, 6));
+        assert_eq!(
+            tokens[7],
+            Token::Text(3, 9, "What's your name?".to_string())
+        );
+
+        // line 4
+        assert_eq!(tokens[8], Token::Text(4, 1, "GREETING".to_string()));
+        assert_eq!(tokens[9], Token::EqualSign(4, 9));
+        assert_eq!(tokens[10], Token::Text(4, 10, "Hello, {NAME}!".to_string()));
+
+        // line 5
+        assert_eq!(
+            tokens[11],
+            Token::Text(5, 1, "DO_YOU_LIKE_OPEN_SOURCE".to_string())
+        );
+        assert_eq!(tokens[12], Token::EqualSign(5, 24));
+        assert_eq!(tokens[13], Token::Text(5, 25, "True".to_string()));
+        assert_eq!(tokens[14], Token::HelpMark(5, 29));
+        assert_eq!(
+            tokens[15],
+            Token::Text(5, 32, "Do you like open-source?".to_string())
+        );
+
+        // line 6
+        assert_eq!(tokens[16], Token::Text(6, 1, "PASSWORD".to_string()));
+        assert_eq!(tokens[17], Token::EqualSign(6, 9));
+        assert_eq!(tokens[18], Token::Text(6, 10, "<random:16>".to_string()));
+    }
+}