diff --git a/sha256.rb b/sha256.rb
index cbe16f3..4d2ef50 100644
--- a/sha256.rb
+++ b/sha256.rb
@@ -11,11 +11,16 @@ if !defined? $input
   # Detect input type (binary, hex, or string)
   $type = input_type($input)
 
+  # Read file if file is given
+  if $type == "file"
+    $input = File.read($input)
+  end
+
   # Convert input to bytes (if possible)
   $bytes = bytes($input, $type)
 
   # Set message (binary representation of data)
-  if $type == "string" || $type == "hex"
+  if $type == "string" || $type == "file" || $type == "hex"
     $message = $bytes.map { |x| x.to_s(2).rjust(8, "0") }.join # convert bytes to binary string
   end
   if $type == "binary"
diff --git a/sha256lib.rb b/sha256lib.rb
index baa59d2..94d988f 100644
--- a/sha256lib.rb
+++ b/sha256lib.rb
@@ -65,24 +65,29 @@ end
 
 # Detect input type base on prefix (i.e. binary, hex, or otherwise just a string)
 def input_type(input)
-  # Check for hex or binary prefix
-  case input[0..1]
-  when "0b"
-    # check it's a valid binary string
-    if input[2..-1] =~ /[^0-1]/ # only 1s and 0s
-      puts "Invalid binary string: #{input}"
-      exit
-    end
-    return "binary"
-  when "0x"
-    # check it's a valid hex string
-    if input[2..-1] !~ /^[0-9A-F]+$/i # only hex chars (case-insensitive)
-      puts "Invalid hex string: #{input}"
-      exit
-    end
-    return "hex"
+  # Check if input is referencing a file
+  if(File.file?(input))
+  	return "file"
   else
-    return "string"
+	  # Check for hex or binary prefix
+	  case input[0..1]
+	  when "0b"
+		# check it's a valid binary string
+		if input[2..-1] =~ /[^0-1]/ # only 1s and 0s
+		  puts "Invalid binary string: #{input}"
+		  exit
+		end
+		return "binary"
+	  when "0x"
+		# check it's a valid hex string
+		if input[2..-1] !~ /^[0-9A-F]+$/i # only hex chars (case-insensitive)
+		  puts "Invalid hex string: #{input}"
+		  exit
+		end
+		return "hex"
+	  else
+		return "string"
+	  end
   end
 end