Move all .cbf files in a directory to another directory

#!/usr/bin/env python
#
# mvAllFilesInDir.py
#
import os, sys, shutil

if len( sys.argv) != 3:
    print( "mvAllFiles.py <srcDir> <destDir>")
    sys.exit(255)

srcDir = sys.argv[1]
destDir = sys.argv[2]

if not os.path.isdir( srcDir):
    print( "mvAllFiles.py: %s is not a directory" % srcDir)
    sys.exit(255)

if not os.path.isdir( destDir):
    print( "mvAllFiles.py: %s is not a directory" % destDir)
    sys.exit(255)

for file in os.listdir( srcDir):
    if file.endswith( ".cbf"):
        shutil.copy( "%s/%s" % (srcDir, file), "%s/%s" % (destDir, file))
        if os.path.getsize( "%s/%s" % (srcDir, file)) != os.path.getsize( "%s/%s" % (destDir, file)):
            print( "%s/%s hasn't been copied properly")
        else:
            os.remove( "%s/%s" % (srcDir, file))
            print( "move %s/%s to %s/%s ok" % (srcDir, file, destDir, file))