diff --git a/src/main.rs b/src/main.rs
index 9b32738..252594c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,24 +1,36 @@
-use std::io::{self};
 use std::collections::BTreeMap;
 use std::env;
+use std::fs::File;
+use std::io::{self, BufRead};
+use std::path::Path;
+
+#[derive(Debug)]
+struct AliasFile {
+    content: io::Lines<io::BufReader<File>>,
+    default_domain: String,
+}
+
 
 fn main() {
     let args: Vec<String> = env::args().collect();
-    if args.len() < 2 {
+    if args.len() < 2 || args.len() % 2 == 0{
         print_help();
         return;
     }
+    let mut alias_files : Vec<AliasFile> = Vec::new();
+    for i in (1..args.len()).step_by(2) {
+        if let Ok(lines) = read_lines(&args[i]) {
+            alias_files.push(AliasFile{content: lines, default_domain: args[i+1].to_string()})
+        }
+    }
     
-    let default_domain = &args[1];
-
-    let redirects = parse_alias_to_map(default_domain);
+    let redirects = parse_alias_to_map(alias_files);
     let sieve_script = generate_sieve_script(redirects);
     println!("{}", sieve_script);
 }
 
 fn generate_sieve_script(redirects: BTreeMap<String, Vec<String>>) -> String {
-//    let mut script : String = "require [\"envelope\", \"copy\"];\n\n".to_string();
-    let mut script : String = "".to_string();
+    let mut script : String = "require [\"envelope\", \"copy\"];\n\n".to_string();
     for (redirect, mut destinations) in redirects {
         script +=  format!("if envelope :is \"to\" \"{}\" {{\n{}}}\n", redirect,
             {
@@ -34,24 +46,26 @@ fn generate_sieve_script(redirects: BTreeMap<String, Vec<String>>) -> String {
     script
 }
 
-fn parse_alias_to_map(default_domain : &str) -> BTreeMap<String, Vec<String>> {
+fn parse_alias_to_map(alias_files: Vec<AliasFile>) -> BTreeMap<String, Vec<String>> {
     // File must exist in the current path
     let mut redirect_map : BTreeMap<String, Vec<String>> = BTreeMap::new();
     let mut destinations : Vec<String> = Vec::new();
-    for line in io::stdin().lines() {
-        let line = line.unwrap();
-        let line = String::from(line.split_at(line.find("#").unwrap_or(line.len())).0);
-        let destination = line.split_at(line.find(char::is_whitespace).unwrap_or(0)).0;
-        if destination.is_empty() {
-            continue;
+    for alias_file in alias_files.into_iter() {
+        for line in alias_file.content {
+            let line = line.unwrap();
+            let line = String::from(line.split_at(line.find("#").unwrap_or(line.len())).0);
+            let destination = line.split_at(line.find(char::is_whitespace).unwrap_or(0)).0;
+            if destination.is_empty() {
+                continue;
+            }
+            let redirects: Vec<String> = line.split_at(line.find(char::is_whitespace).unwrap_or(0)).1.split(" ")
+                .filter(|address| address.trim().to_string().replace(",","") != "").map(|addr| to_mailaddress(addr, &alias_file.default_domain)).collect();
+            if redirects.is_empty() {
+                continue;
+            }
+            destinations.push(to_mailaddress(destination, &alias_file.default_domain));
+            redirect_map.insert(to_mailaddress(destination, &alias_file.default_domain), redirects);
         }
-        let redirects: Vec<String> = line.split_at(line.find(char::is_whitespace).unwrap_or(0)).1.split(" ")
-            .filter(|address| address.trim().to_string().replace(",","") != "").map(|addr| to_mailaddress(addr, default_domain)).collect();
-        if redirects.is_empty() {
-            continue;
-        }
-        destinations.push(to_mailaddress(destination, default_domain));
-        redirect_map.insert(to_mailaddress(destination, default_domain), redirects);
     }
     let mut changed = true; 
     while changed {
@@ -74,7 +88,7 @@ fn parse_alias_to_map(default_domain : &str) -> BTreeMap<String, Vec<String>> {
     redirect_map
 }
 
-fn to_mailaddress(local_part: &str, default_domain : &str) -> String {
+fn to_mailaddress(local_part: &str, default_domain : &String) -> String {
     let mut addr = local_part.trim().to_string();
     addr = addr.replace(",", "");
     if addr.contains("@") {
@@ -83,7 +97,17 @@ fn to_mailaddress(local_part: &str, default_domain : &str) -> String {
     addr + "@" + default_domain
 }
 
-fn print_help(){
-    print!("Reads a virtual alias file from STDIN and needs a default domain to append to local paths, e.g.
-    cat virt_aliases | ./alias_to_sieve example.com");
+
+// The output is wrapped in a Result to allow matching on errors.
+// Returns an Iterator to the Reader of the lines of the file.
+fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
+where P: AsRef<Path>, {
+    let file = File::open(filename)?;
+    Ok(io::BufReader::new(file).lines())
+}
+
+
+fn print_help(){
+    print!("Reads a virtual alias file and needs a default domain to append to local paths, e.g.
+    ./alias_to_sieve example.com.txt example.com ");
 }