--- a/textshaper/indent.py	Fri Jan 17 18:17:59 2014 -0800
+++ b/textshaper/indent.py	Sat Jan 18 09:28:55 2014 -0800
@@ -39,12 +39,35 @@
                 index = indentation
             retval.append(line[index:])
 
+    return retval
+
+
 def main(args=sys.argv[1:]):
 
-    usage = '%prog [options]'
+    # parse command line
+    usage = '%prog [options] [file] [file2] [...]'
+    description = """indent files or stdin if no files given"""
     parser = optparse.OptionParser(usage=usage, description=__doc__)
-    options, args = parser.parse_args(args)
+    parser.add_option('-o', '--output', dest='output',
+                      help="output file or stdout if not given")
+    options, files = parser.parse_args(args)
 
+    # input from files or stdin
+    if files:
+        missing = [not os.path.exists(filename) for filename in files]
+        if missing:
+            parser.error("File(s) not found: %s" % ', '.join(missing))
+        def _files():
+            for filename in files:
+                with open(f, 'r') as f:
+                    yield f
+    else:
+        def _files():
+            yield sys.stdin
+
+    # process input
+    for f in _files():
+        print f
 
 if __name__ == '__main__':
     main()