diff --git a/README.md b/README.md
index 1945d69..4fca84f 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ Pdfc --  PDF Compressor
 Simple python script to compress PDF.
 
 Installation
--------------
+---- 
 * Install dependency Ghostscript.
 On MacOSX: `brew install ghostscript`
 On Windows: install binaries via [official website] (https://www.ghostscript.com/)
@@ -14,23 +14,25 @@ On Windows: install binaries via [official website] (https://www.ghostscript.com
 On MacOSX:
 `echo export=/absolute/path/of/the/folder/script/:$PATH >> ~/.bash_profile`
 
+Or with ZSH 
+`echo path+=absolute/path/of/the/folder/script/ >> ~/.zshrc`
+
 Usage
------
+---- 
 `pdfc [-o output_file_path] [-c number] input_file_path`
 
 Ex:
 `pdfc -o out.pdf in.pdf`
 
 Output:
-```
-Compress PDF...
-Compression by 65%.
-Final file size is 1.4MB
-Done.
-```
+	Compress PDF...
+	Compression by 65%.
+	Final file size is 1.4MB
+	Done.
 
+When compression did not work, the file is skipped.
 Options
--------
+---- 
 * `-c` or `--compress` specifies 5 levels of compression, similar to standard pdf generator level:
   * 0: default
   * 1: prepress
diff --git a/pdf_compressor.py b/pdf_compressor.py
index 40a25ad..f5f25c9 100755
--- a/pdf_compressor.py
+++ b/pdf_compressor.py
@@ -24,7 +24,7 @@
 from shutil import copyfile
 
 
-def compress(input_file_path, output_file_path, power=0):
+def compress(input_file_path, output_file_path, backup, power=0):
     """Function to compress PDF via Ghostscript command line interface"""
     quality = {
         0: '/default',
@@ -46,19 +46,51 @@ def compress(input_file_path, output_file_path, power=0):
         sys.exit(1)
 
     print("Compress PDF...")
-    initial_size = os.path.getsize(input_file_path)
     subprocess.call(['gs', '-sDEVICE=pdfwrite', '-dCompatibilityLevel=1.4',
                     '-dPDFSETTINGS={}'.format(quality[power]),
                     '-dNOPAUSE', '-dQUIET', '-dBATCH',
                     '-sOutputFile={}'.format(output_file_path),
                      input_file_path]
     )
+    
+    initial_size = os.path.getsize(input_file_path)
     final_size = os.path.getsize(output_file_path)
-    ratio = 1 - (final_size / initial_size)
-    print("Compression by {0:.0%}.".format(ratio))
-    print("Final file size is {0:.1f}MB".format(final_size / 1000000))
-    print("Done.")
 
+    # Check if compressing was resourceful
+    if (final_size > initial_size) or (final_size == initial_size):
+        os.remove(output_file_path)
+        print("Skipped")
+    # In case no output file is specified, erase original file
+    elif output_file_path == 'temp.pdf':
+        if backup:
+            copyfile(input_file_path, input_file_path.replace(".pdf", "_BACKUP.pdf"))
+        os.remove(input_file_path)
+        copyfile(output_file_path, input_file_path)
+        os.remove(output_file_path)
+
+        ratio = 1 - (final_size / initial_size)
+        print("Compression by {0:.0%}.".format(ratio))
+        print("Final file size is {0:.1f}MB".format(final_size / 1000000))
+        print("Done.")
+
+def compress_directory(input_dir_path, backup, power=0):
+    
+    # Default File Path
+    output_file_path = os.path.join(input_dir_path, "temp.pdf")
+
+    # The extension to search for
+    exten = '.pdf'
+
+    for dirpath, dirnames, files in os.walk(input_dir_path):
+        
+        for name in files:
+            if name.lower().endswith(exten):
+                file_path = os.path.join(dirpath, name)
+                compress(file_path, output_file_path, backup, power)
+        
+        for dirname in dirnames:
+            new_dir_path = os.path.join(dirpath, dirname)
+            compress_directory(new_dir_path, backup, power)
 
 def main():
     parser = argparse.ArgumentParser(
@@ -80,22 +112,25 @@ def main():
     if not args.out:
         args.out = 'temp.pdf'
 
-    # Run
-    compress(args.input, args.out, power=args.compress)
 
-    # In case no output file is specified, erase original file
-    if args.out == 'temp.pdf':
-        if args.backup:
-            copyfile(args.input, args.input.replace(".pdf", "_BACKUP.pdf"))
-        copyfile(args.out, args.input)
-        os.remove(args.out)
-
-    # In case we want to open the file after compression
-    if args.open:
-        if args.out == 'temp.pdf' and args.backup:
-            subprocess.call(['open', args.input])
-        else:
-            subprocess.call(['open', args.out])
+    if os.path.isdir(args.input):
+        compress_directory(args.input, args.backup, power=args.compress)
+    elif os.path.isfile(args.input):
+        # Run
+        compress(args.input, args.out, args.backup, power=args.compress)
+
+        # In case we want to open the file after compression
+        if args.open:
+            if args.out == 'temp.pdf' and args.backup:
+                subprocess.call(['open', args.input])
+            else:
+                subprocess.call(['open', args.out])
+
+    else:
+        print("Error: invalid path for input PDF file")
+        sys.exit(1)
+    
+
 
 if __name__ == '__main__':
     main()