update README.md with new binary instructions

Author: faessler

README.md

@@ -1,8 +1,20 @@
-# Bash write img to disk
+# Write img to disk
+Simple bash script that writes an iso or img file to a USB or SD card. 
+The bash script is now also available as binary.
 
-Simple bash script that writes an iso or img file to a USB or SD card.
+## Installation
+### Option 1: Bash script
+Download the bash script file and execute it like this `bash script.sh`.
 
-Download the bash file and execute it like this `bash script.sh`.
-Follow the instructions in the terminal.
+## Option 2: Binary (Beta)
+1. Run `sudo curl https://raw.githubusercontent.com/faessler/bash-write-img-to-disk/master/witd -o /usr/local/bin/witd && sudo chmod 755 witd` to download the binary and put it in _/usr/local/bin_.
+2. After that you can execute `witd` from anywhere.
+
+Note: You can put the binary also in another directory if you don't want to use _/user/local/bin_. If you use _/user/local/bin_ make sure that the directory exists and is in your path (`echo $PATH`). Execute `export PATH=$PATH:/usr/local/bin` to add it to your path.
 
+## Preview
+Follow the instructions in the terminal.
 ![Terminal Preview](./preview.png)
+
+## Development
+Update binary: `shc -f ./script.sh -o ./witd`