import ftplib, sys 
ftp1 = ftplib.FTP("127.0.0.1", "book", "bookpw") 
ftp1.cwd("/Dir") 
ftp2 = ftplib.FTP("www.holdenweb.com", "bookuser", "bookpw") 
ftp2.cwd("/public") 
sock1 = ftp1.transfercmd("RETR a.zip") 
sock2 = ftp2.transfercmd("STOR b.zip") 
  
flen = 0                            
while 1: 
    block = sock1.recv(1024)        
    if len(block) == 0:             
        break 
    flen += len(block)              
    while len(block) > 0:           
        sentlen = sock2.send(block) 
        block = block[sentlen:]     
          
print "Transferred", flen, "bytes" 
  
sock1.close() 
sock2.close() 
ftp1.quit() 
ftp2.quit()