@@ -1,29 +1,89 @@
 #! /usr/bin/env python
 
 """Python utility to print MD5 checksums of argument files.
-
-Works with Python 2.1 and later.
 """
 
-import sys, md5
 
-BLOCKSIZE = 1024*1024
+bufsize = 8096
+fnfilter = None
+rmode = 'r'
 
-def main():
-    args = sys.argv[1:]
-    if not args:
-        sys.stderr.write("usage: %s file ...\n" % sys.argv[0])
-        sys.exit(2)
-    for file in sys.argv[1:]:
-        f = open(file, "rb")
-        sum = md5.new()
+usage = """
+usage: sum5 [-b] [-t] [-l] [-s bufsize] [file ...]
+-b        : read files in binary mode
+-t        : read files in text mode (default)
+-l        : print last pathname component only
+-s bufsize: read buffer size (default %d)
+file ...  : files to sum; '-' or no files means stdin
+""" % bufsize
+
+import sys
+import os
+import getopt
+import md5
+
+def sum(*files):
+    sts = 0
+    if files and isinstance(files[-1], file):
+        out, files = files[-1], files[:-1]
+    else:
+        out = sys.stdout
+    if len(files) == 1 and not isinstance(files[0], str):
+        files = files[0]
+    for f in files:
+        if isinstance(f, str):
+            if f == '-':
+                sts = printsumfp(sys.stdin, '<stdin>', out) or sts
+            else:
+                sts = printsum(f, out) or sts
+        else:
+            sts = sum(f, out) or sts
+    return sts
+
+def printsum(filename, out = sys.stdout):
+    try:
+        fp = open(filename, rmode)
+    except IOError, msg:
+        sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
+        return 1
+    if fnfilter:
+        filename = fnfilter(filename)
+    sts = printsumfp(fp, filename, out)
+    fp.close()
+    return sts
+
+def printsumfp(fp, filename, out = sys.stdout):
+    m = md5.new()
+    try:
         while 1:
-            block = f.read(BLOCKSIZE)
-            if not block:
-                break
-            sum.update(block)
-        f.close()
-        print sum.hexdigest(), file
-
-if __name__ == "__main__":
-    main()
+            data = fp.read(bufsize)
+            if not data: break
+            m.update(data)
+    except IOError, msg:
+        sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))
+        return 1
+    out.write('%s %s\n' % (m.hexdigest(), filename))
+    return 0
+
+def main(args = sys.argv[1:], out = sys.stdout):
+    global fnfilter, rmode, bufsize
+    try:
+        opts, args = getopt.getopt(args, 'blts:')
+    except getopt.error, msg:
+        sys.stderr.write('%s: %s\n%s' % (sys.argv[0], msg, usage))
+        return 2
+    for o, a in opts:
+        if o == '-l':
+            fnfilter = os.path.basename
+        if o == '-b':
+            rmode = 'rb'
+        if o == '-t':
+            rmode = 'r'
+        if o == '-s':
+            bufsize = int(a)
+    if not args:
+        args = ['-']
+    return sum(args, out)
+
+if __name__ == '__main__' or __name__ == sys.argv[0]:
+    sys.exit(main(sys.argv[1:], sys.stdout))