zip 错误：命令参数无效（无法将 zip 文件写入终端）

Question

我正在学习《Python 咬一口》这本书。输入书上的例子后

import os
import time

# 1. The files and directories to be backed up are
# specified in a list.
# Example on Windows:
# source = ['"C:\\MY Documents"', 'C:\\Code']
# Example on Mac OS X and Linux:
source = ['/home/username/Downloads/books']
# Notice we had to use double quotes inside the string
# for  names with spaces in it.

# 2. The backup must be stored in a 
# main backup directory
# Example on Windows:
# target_dir = 'E:\\Backup'
# Example on Mac OS X and Linux:
target_dir = '/home/username/Downloads/backup'
# Remember to change this to which folder you will be using

# 3. The files are backed up into a zip file.
# 4. The name of the zip archive is the current date and time
target = target_dir + os.sep + \
        time.strftime('%Y%m%d%H%M%S') + '.zip'

# Create target directory if it is not present
if not os.path.exists(target_dir):
    os.mkdir(target_dir)    # make directory

# 5. We use the zip commond to put the files in a zip archive
zip_command = "zip - r {0} {1}".format(target, ' '.join(source))

# Run the backup
print "Zip command is:"
print zip_command
print "Running:"
if os.system(zip_command) == 0:
    print 'Successful backup to', target
else:
    print 'Backup FALIED'

我收到一条消息，zip error: Invalid command arguments (cannot write zip file to terminal) 我不知道哪里出了问题，我在本书中输入了相同的代码。有谁知道为什么会发生这种情况？

Answer 1

问题在于您正在创建的命令中，和zip之间有一个额外的空格。例子 --r

zip_command = "zip - r {0} {1}".format(target, ' '.join(source))
                    ^
Notice the extra space

-和之间不应有空格r。例子 -

zip_command = "zip -r {0} {1}".format(target, ' '.join(source))

另外，我想建议，最好使用subprocess.call()而不是使用os.system，为它提供命令的参数列表。例子 -

import subprocess
zip_command = ['zip','-r',target]
for s in source:
    zip_command.append(s)
subprocess.call(zip_command)

这样会更容易看到错误。