diff --git a/src/main.rs b/src/main.rs
index f33a6a8..ef67107 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,8 @@ extern crate argparse;
 
 use std::io::*;
 use std::fs::*;
+use std::process::Command;
+use std::path::Path;
 
 mod c_code;
 use c_code::*;
@@ -78,7 +80,7 @@ fn parse_args() -> CmdArgs {
 }
 
 fn main() {
-    let args = parse_args();
+    let mut args = parse_args();
     // write information header
     println!("// This source code was generated by anyexec2c.");
     println!("// Link: https://github.com/exyi/anyexec2C");
@@ -86,6 +88,12 @@ fn main() {
 
     // write the actual source code as C comments
     for f in args.comment_files {
+        let path = Path::new(&f);
+        if !path.exists() {
+            eprintln!("{} - file does not exist!", f);
+            ::std::process::exit(1);
+        }
+
         println!("// ==============================", );
         println!("// {}", f);
         println!("// ==============================");
@@ -100,8 +108,51 @@ fn main() {
     }
 
     // build executable
-    //TODO
-    //TODO insert into args.exec_file
+    if let Some(build_file) = args.build_file {
+        let extension = build_file.clone();
+        let extension = extension.split(".").last();
+        if extension.is_none() {
+            eprintln!("Failed to split extension off build file name");
+            ::std::process::exit(1);
+        }
+        let extension = extension.unwrap();
+        match extension {
+            // D lang
+            "d" => {
+                let output = Command::new("dmd")
+                    .arg("-O")
+                    .arg(build_file)
+                    .arg("-of=a.out")
+                    .arg(format!("-od={}",::std::env::temp_dir().as_os_str().to_str().expect("TMP dir has non-unicode name!")))
+                    .output()
+                    .expect("Failed to execute DMD to compile D source");
+                // Check output and print it to stderr...
+                {
+                    let stderr = ::std::io::stderr();
+                    let mut handle = stderr.lock();
+                    let _result = handle.write_all(&output.stdout);
+                    let _result = handle.write_all(&output.stderr);
+                }
+
+                if !output.status.success() {
+                    eprintln!("\nCompilation error!");
+                    ::std::process::exit(1);
+                }
+                
+                // Check for compiled binary existence
+                let path = Path::new("a.out");
+                if !path.exists() {
+                    eprintln!("Couldn't find compiled binary... Failed.");
+                    ::std::process::exit(1);
+                }
+                args.exec_file = Some(String::from("a.out"));
+            }
+            _ => {
+                eprintln!("File extension not recognized! Can't build!");
+                ::std::process::exit(1);
+            }
+        }
+    }
 
     // read executable
     let exec_file = args.exec_file.unwrap();