diff -urN v2/bk.py v3/bk.py
--- v2/bk.py	2018-02-15 12:42:28.000000000 +0900
+++ v3/bk.py	2018-05-05 09:35:39.000000000 +0900
@@ -6,7 +6,7 @@
 import subprocess
 
 def exit(msg='', code=0):
-	print msg
+	print(msg)
 	sys.exit(code)
 
 exec_cmd = lambda cmd: subprocess.check_output(cmd, shell=True)
@@ -41,6 +41,7 @@
 	if path in db:
 		return
 	s = exec_cmd( "find '{}' -type f -or -type l".format(path) )
+	s = s.decode()
 	if not s:
 		return
 	lst = s.strip().split('\n')
@@ -66,8 +67,8 @@
 	db_s = db.get(s, {})
 	db_d = db.get(d, {})
 
-	need_copy = lambda (k, v): k not in db_d or not is_same(db_d.get(k), v)
-	items = filter( need_copy, db_s.items() )
+	need_copy = lambda k, v: k not in db_d or not is_same(db_d.get(k), v)
+	items = filter( lambda kv: need_copy(kv[0], kv[1]), db_s.items() )
 	if not items:
 		return ([], [])
 	(lst, _) = zip(*items)
@@ -77,8 +78,9 @@
 
 def get_disk_free(path):
 	s = exec_cmd( "df -k '{}'".format(path) )
+	s = s.decode()
 	lst = s.strip().split('\n')
-	lst = map( lambda s: s.split(), lst )
+	lst = list( map( lambda s: s.split(), lst ) )
 	i = lst[0].index('Available') # !
 	return int( lst[1][i] ) * 1024
 
@@ -132,7 +134,7 @@
 		dst_free -= sz
 		cp_sz += sz
 
-		print kmgt_str(cp_sz) + ' / ' + kmgt_str(add_sz) + ' : ' + p + ' / ' + kmgt_str(sz)
+		print(kmgt_str(cp_sz) + ' / ' + kmgt_str(add_sz) + ' : ' + p + ' / ' + kmgt_str(sz))
 
 	for k in lst:
 		db_d[k] = db_s.get(k).copy()