diff --git a/Cargo.lock b/Cargo.lock
index 19e1160..18a6f96 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -371,6 +371,7 @@ dependencies = [
 name = "md2pdf"
 version = "0.1.0"
 dependencies = [
+ "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "pulldown-cmark 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "tectonic 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index a339bc1..c3fa533 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,6 +2,7 @@
 name = "md2pdf"
 version = "0.1.0"
 authors = ["Thomas Forgione <thomas@forgione.fr>"]
+description = "A small utility to convert markdown files to pdf exploiting tectonic."
 edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -9,3 +10,4 @@ edition = "2018"
 [dependencies]
 tectonic = "0.1.11"
 pulldown-cmark = "0.5.2"
+clap = "2.33.0"
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..e8bcdf8
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,130 @@
+use pulldown_cmark::{Event, Parser, Tag};
+
+pub const LATEX_HEADER:&str = r#"\documentclass{scrartcl}
+\usepackage{graphicx}
+\usepackage{hyperref}
+\usepackage{listings}
+\usepackage{xcolor}
+\definecolor{colKeys}{rgb}{0,0.5,0}
+\definecolor{colIdentifier}{rgb}{0,0,0}
+\definecolor{colComments}{rgb}{0,0.5,1}
+\definecolor{colString}{rgb}{0.6,0.1,0.1}
+\definecolor{colBackground}{rgb}{0.95,0.95,1}
+\lstset{%configuration de listings
+   float=hbp,%
+   basicstyle=\ttfamily\small,%
+   %
+   identifierstyle=\color{colIdentifier}, %
+   keywordstyle=\color{colKeys}, %
+   stringstyle=\color{colString}, %
+   commentstyle=\color{colComments}\textit, %
+   %
+   backgroundcolor=\color{colBackground},%
+   %
+   columns=flexible, %
+   tabsize=2, %
+   frame=trbl, %
+   %frameround=tttt,%
+   extendedchars=true, %
+   showspaces=false, %
+   showstringspaces=false, %
+   numbers=left, %
+   numberstyle=\tiny, %
+   breaklines=true, %
+   breakautoindent=true, %
+   captionpos=b,%
+   xrightmargin=0.2cm, %
+   xleftmargin=0.2cm
+}
+\begin{document}
+"#;
+
+pub const LATEX_FOOTER: &str = "\n\\end{document}\n";
+
+pub fn markdown_to_latex(markdown: String) -> String {
+    let mut output = String::from(LATEX_HEADER);
+
+    let parser = Parser::new(&markdown);
+
+    for event in parser {
+        match event {
+            Event::Start(Tag::Header(level)) => {
+                output.push_str("\\");
+                for _ in 1 .. level {
+                    output.push_str("sub");
+                }
+                output.push_str("section{");
+            },
+            Event::End(Tag::Header(_)) => output.push_str("}\n"),
+
+            Event::Start(Tag::Emphasis) => output.push_str("\\emph{"),
+            Event::End(Tag::Emphasis) => output.push_str("}"),
+
+            Event::Start(Tag::Strong) => output.push_str("\\textbf{"),
+            Event::End(Tag::Strong) => output.push_str("}"),
+
+            Event::Start(Tag::List(None)) => output.push_str("\\begin{itemize}\n"),
+            Event::End(Tag::List(None)) => output.push_str("\\end{itemize}\n"),
+
+            Event::Start(Tag::List(Some(_))) => output.push_str("\\begin{enumerate}\n"),
+            Event::End(Tag::List(Some(_))) => output.push_str("\\end{enumerate}\n"),
+
+            Event::Start(Tag::Link(_, url, _)) => {
+                output.push_str("\\href{");
+                output.push_str(&*url);
+                output.push_str("}{");
+            },
+
+            Event::End(Tag::Link(_, _, _)) => {
+                output.push_str("}");
+            },
+
+            Event::Start(Tag::Image(_, path, title)) => {
+                output.push_str("\\begin{figure}\n");
+                output.push_str("\\centering\n");
+                output.push_str("\\includegraphics[width=\\textwidth]{");;
+                output.push_str(&*path);
+                output.push_str("}\n");
+                output.push_str("\\caption{");
+                output.push_str(&*title);
+                output.push_str("}\n\\end{figure}\n");
+            },
+
+            Event::Start(Tag::Item) => output.push_str("\\item "),
+            Event::End(Tag::Item) => output.push_str("\n"),
+
+            Event::Start(Tag::CodeBlock(lang)) => {
+                if ! lang.is_empty() {
+                    output.push_str("\\begin{lstlisting}[language=");
+                    output.push_str(&*lang);
+                    output.push_str("]\n");
+                } else {
+                    output.push_str("\\begin{lstlisting}\n");
+                }
+            },
+
+            Event::End(Tag::CodeBlock(_)) => {
+                output.push_str("\n\\end{lstlisting}\n");
+            },
+
+            Event::Text(t) => {
+                output.push_str(&*t);
+            },
+
+            Event::SoftBreak => {
+                output.push('\n');
+            },
+
+            _ => (),
+        }
+    }
+
+    output.push_str(LATEX_FOOTER);
+
+    output
+}
+
+pub fn markdown_to_pdf(markdown: String) -> Result<Vec<u8>, tectonic::Error> {
+    tectonic::latex_to_pdf(markdown_to_latex(markdown))
+}
+
diff --git a/src/main.rs b/src/main.rs
index 5e2e871..c1d40c7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,115 +1,60 @@
 use std::fs::File;
 use std::io::{Read, Write};
+use std::process::exit;
 
-use pulldown_cmark::{Event, Parser, Tag};
+use clap::{crate_authors, crate_description, crate_name, crate_version, App, Arg};
+
+use md2pdf::{markdown_to_latex, markdown_to_pdf};
+
+macro_rules! unwrap {
+    ($e: expr, $m: expr) => {
+        match $e {
+            Ok(v) => v,
+            Err(e) => {
+                eprintln!("{}: {}", $m, e);
+                exit(1);
+            }
+        }
+    }
+}
 
 fn main() {
 
-    let mut markdown_input = String::new();
-    let mut input = File::open("markdown.md").unwrap();
-    input.read_to_string(&mut markdown_input).unwrap();
+    let matches = App::new(crate_name!())
+        .bin_name(crate_name!())
+        .version(crate_version!())
+        .author(crate_authors!("\n"))
+        .about(crate_description!())
+        .arg(Arg::with_name("INPUT")
+             .long("input")
+             .short("i")
+             .help("Input markdown files")
+             .required(true)
+             .takes_value(true))
+        .arg(Arg::with_name("OUTPUT")
+             .long("output")
+             .short("o")
+             .help("Output tex or pdf file")
+             .required(true)
+             .takes_value(true))
+        .get_matches();
 
-    let parser = Parser::new(&markdown_input);
+    let mut content = String::new();
+    let mut input = unwrap!(File::open(matches.value_of("INPUT").unwrap()), "couldn't open input file");
+    unwrap!(input.read_to_string(&mut content), "couldn't read file content");
 
-    let mut tex_output = String::new();
-    tex_output.push_str("\\documentclass{scrartcl}\n");
-    tex_output.push_str("\\usepackage{graphicx}\n");
-    tex_output.push_str("\\usepackage{listings}\n");
-    tex_output.push_str("\\usepackage{xcolor}\n");
-    tex_output.push_str("\\definecolor{colKeys}{rgb}{0,0.5,0}\n");
-    tex_output.push_str("\\definecolor{colIdentifier}{rgb}{0,0,0}\n");
-    tex_output.push_str("\\definecolor{colComments}{rgb}{0,0.5,1}\n");
-    tex_output.push_str("\\definecolor{colString}{rgb}{0.6,0.1,0.1}\n");
-    tex_output.push_str("\\definecolor{colBackground}{rgb}{0.95,0.95,1}\n");
-    tex_output.push_str("\\lstset{%configuration de listings\n");
-    tex_output.push_str("    float=hbp,%\n");
-    tex_output.push_str("    basicstyle=\\ttfamily\\small,%\n");
-    tex_output.push_str("    %\n");
-    tex_output.push_str("    identifierstyle=\\color{colIdentifier}, %\n");
-    tex_output.push_str("    keywordstyle=\\color{colKeys}, %\n");
-    tex_output.push_str("    stringstyle=\\color{colString}, %\n");
-    tex_output.push_str("    commentstyle=\\color{colComments}\textit, %\n");
-    tex_output.push_str("    %\n");
-    tex_output.push_str("    backgroundcolor=\\color{colBackground},%\n");
-    tex_output.push_str("    %\n");
-    tex_output.push_str("    columns=flexible, %\n");
-    tex_output.push_str("    tabsize=2, %\n");
-    tex_output.push_str("    frame=trbl, %\n");
-    tex_output.push_str("    %frameround=tttt,%\n");
-    tex_output.push_str("    extendedchars=true, %\n");
-    tex_output.push_str("    showspaces=false, %\n");
-    tex_output.push_str("    showstringspaces=false, %\n");
-    tex_output.push_str("    numbers=left, %\n");
-    tex_output.push_str("    numberstyle=\\tiny, %\n");
-    tex_output.push_str("    breaklines=true, %\n");
-    tex_output.push_str("    breakautoindent=true, %\n");
-    tex_output.push_str("    captionpos=b,%\n");
-    tex_output.push_str("    xrightmargin=0.2cm, %\n");
-    tex_output.push_str("    xleftmargin=0.2cm\n");
-    tex_output.push_str("}\n");
-    tex_output.push_str("\\begin{document}\n");
+    let output_path = matches.value_of("OUTPUT").unwrap();
+    let mut output = unwrap!(File::create(output_path), "couldn't open output file");
 
-    for event in parser {
-        match event {
-            Event::Start(Tag::Header(level)) => {
-                tex_output.push_str("\\");
-                for _ in 1 .. level {
-                    tex_output.push_str("sub");
-                }
-                tex_output.push_str("section{");
-            },
-            Event::End(Tag::Header(_)) => tex_output.push_str("}\n"),
-
-            Event::Start(Tag::Emphasis) => tex_output.push_str("\\emph{"),
-            Event::End(Tag::Emphasis) => tex_output.push_str("}"),
-
-            Event::Start(Tag::Strong) => tex_output.push_str("\\textbf{"),
-            Event::End(Tag::Strong) => tex_output.push_str("}"),
-
-            Event::Start(Tag::List(None)) => tex_output.push_str("\\begin{itemize}\n"),
-            Event::End(Tag::List(None)) => tex_output.push_str("\\end{itemize}\n"),
-
-            Event::Start(Tag::List(Some(_))) => tex_output.push_str("\\begin{enumerate}\n"),
-            Event::End(Tag::List(Some(_))) => tex_output.push_str("\\end{enumerate}\n"),
-
-            Event::Start(Tag::Image(_, path, title)) => {
-                tex_output.push_str("\\begin{figure}\n");
-                tex_output.push_str("\\centering\n");
-                tex_output.push_str("\\includegraphics[width=\\textwidth]{");;
-                tex_output.push_str(&*path);
-                tex_output.push_str("}\n");
-                tex_output.push_str("\\caption{");
-                tex_output.push_str(&*title);
-                tex_output.push_str("}\n\\end{figure}\n");
-            },
-
-            Event::Start(Tag::Item) => tex_output.push_str("\\item "),
-            Event::End(Tag::Item) => tex_output.push_str("\n"),
-
-            Event::Start(Tag::CodeBlock(lang)) => {
-                if ! lang.is_empty() {
-                    tex_output.push_str("\\begin{lstlisting}[language=");
-                    tex_output.push_str(&*lang);
-                    tex_output.push_str("]\n");
-                } else {
-                    tex_output.push_str("\\begin{lstlisting}\n");
-                }
-            },
-
-            Event::End(Tag::CodeBlock(_)) => {
-                tex_output.push_str("\n\\end{lstlisting}\n");
-            }
-
-            Event::Text(t) => tex_output.push_str(&*t),
-            _ => (),
-        }
+    if output_path.ends_with(".tex") {
+        let tex = markdown_to_latex(content);
+        unwrap!(output.write(tex.as_bytes()), "couldn't write output file");
+    } else if output_path.ends_with(".pdf") {
+        let data = unwrap!(markdown_to_pdf(content), "error while compiling latex, this is most likely a bug");
+        unwrap!(output.write(&data), "coudln't write output file");
+    } else {
+        eprintln!("unknown file format for output: {}", output_path);
+        exit(1);
     }
 
-    tex_output.push_str("\n\\end{document}\n");
-
-    println!("{}", tex_output);
-
-    let pdf_data = tectonic::latex_to_pdf(tex_output).expect("processing failed");
-    let mut output = File::create("output.pdf").unwrap();
-    output.write(&pdf_data).unwrap();
 }