diff --git a/src/base.rs b/src/base.rs
index a39f4bf..8655227 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -181,7 +181,7 @@ pub fn get_oid(mut name: String) -> String {
         format!("refs/heads/{}", name),
     ];
 
-    for reference in refs_to_try.into_iter() {
+    for reference in refs_to_try.iter() {
         let found = data::get_ref(reference.clone(), false);
         if found.value != "" {
             return found.value;
@@ -268,6 +268,11 @@ fn is_ignored(path: &String) -> bool {
 
 fn tree_entries(oid: String) -> Vec<(String, String, String)> {
     let mut entries: Vec<(String, String, String)> = vec![];
+
+    if oid == "".to_owned() {
+        return entries;
+    }
+
     let tree_data = data::get_object(oid, "tree".to_owned());
     for line in tree_data.split_terminator("\n") {
         let items: Vec<&str> = line.splitn(3, " ").collect();
@@ -280,7 +285,7 @@ fn tree_entries(oid: String) -> Vec<(String, String, String)> {
     return entries;
 }
 
-fn get_tree(oid: String, base_path: String) -> HashMap<String, String> {
+pub fn get_tree(oid: String, base_path: String) -> HashMap<String, String> {
     let mut result = HashMap::new();
     for entry in tree_entries(oid) {
         // _type, oid, name
diff --git a/src/diff.rs b/src/diff.rs
new file mode 100644
index 0000000..4fdd388
--- /dev/null
+++ b/src/diff.rs
@@ -0,0 +1,33 @@
+use std::collections::HashMap;
+
+fn compare_trees(trees: Vec<HashMap<String, String>>) -> HashMap<String, Vec<String>> {
+    let len_trees = trees.len();
+    let mut entries: HashMap<String, Vec<String>> = HashMap::new();
+
+    for (i, tree) in trees.iter().enumerate() {
+        for (path, oid) in tree {
+            if entries.contains_key(path) {
+                entries.get_mut(path).unwrap()[i] = oid.clone();
+            } else {
+                entries.insert(path.clone(), vec!["".to_owned(); len_trees]);
+                entries.get_mut(path).unwrap()[i] = oid.clone();
+            }
+        }
+    }
+
+    return entries;
+}
+
+pub fn diff_trees(t_from: HashMap<String, String>, t_to: HashMap<String, String>) -> String {
+    let mut output = "".to_owned();
+    let trees = vec![t_from, t_to];
+    for (path, oids) in compare_trees(trees).iter() {
+        let o_from = oids[0].clone();
+        let o_to = oids[1].clone();
+        if o_from != o_to {
+            output.push_str(format!("changed {}\n", path).as_str());
+        }
+    }
+
+    return output;
+}
diff --git a/src/main.rs b/src/main.rs
index e8c7680..7bd144f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,10 +1,11 @@
 use clap::{App, Arg, ArgMatches, SubCommand};
-use std::collections::{HashMap, HashSet, VecDeque};
+use std::collections::{HashMap, VecDeque};
 use std::fs;
 use std::io::Write;
 use std::process::{Command, Stdio};
 mod base;
 mod data;
+mod diff;
 
 fn main() {
     let matches = App::new("rgit vcs")
@@ -264,7 +265,18 @@ fn show(matches: ArgMatches) {
         let oid = base::get_oid(cmd_matches.value_of("oid").unwrap().to_owned());
         let commit = base::get_commit(oid.clone());
         let refs: HashMap<String, Vec<String>> = HashMap::new();
-        print_commit(oid, &commit, refs)
+        let parent_tree = if commit.parent != "".to_owned() {
+            base::get_commit(commit.parent.clone()).tree
+        } else {
+            "".to_owned()
+        };
+
+        print_commit(oid, &commit, refs);
+        let result = diff::diff_trees(
+            base::get_tree(parent_tree, "".to_owned()),
+            base::get_tree(commit.tree, "".to_owned()),
+        );
+        println!("{}", result);
     }
 }