diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..a79dd23
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 Tsuji Daishiro
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
index 18a5fa0..25c43ef 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,11 @@ git clone https://github.com/d-tsuji/ttycopy.git
 cd ttycopy
 ```
 
+REQUIRE
+-----
+
+- strace
+
 USAGE
 -----
 
@@ -35,4 +40,4 @@ If you want to scan tty of USER dai001, type:
   [root@host root]# ./ttycopy pts/4
 ```
 
-![ttycopy](https://user-images.githubusercontent.com/24369487/68991645-2bc1c780-08a4-11ea-81c8-3f4af99bedb2.gif)
\ No newline at end of file
+![ttycopy](https://user-images.githubusercontent.com/24369487/68991645-2bc1c780-08a4-11ea-81c8-3f4af99bedb2.gif)