python 文件分割 脚本

!/usr/bin/python

""" ################################################################################ split a file into a set of parts; join.py puts them back together; this is a customizable version of the standard Unix split command-line utility; because it is written in Python, it also works on Windows and can be easily modified; because it exports a function, its logic can also be imported and reused in other applications; ################################################################################ """

import sys, os kilobytes = 1024 megabytes = kilobytes * 1000 chunksize = int(1.4 * megabytes) # default: roughly a floppy

def split(fromfile, todir, chunksize=chunksize): if not os.path.exists(todir): # caller handles errors os.mkdir(todir) # make dir, read/write parts else: for fname in os.listdir(todir): # delete any existing files os.remove(os.path.join(todir, fname)) partnum = 0 input = open(fromfile, 'rb') # use binary mode on Windows while True: # eof=empty string from read chunk = input.read(chunksize) # get next part <= chunksize if not chunk: break partnum += 1 filename = os.path.join(todir, ('part%04d' % partnum)) fileobj = open(filename, 'wb') fileobj.write(chunk) fileobj.close() # or simply open().write() input.close() assert partnum <= 9999 # join sort fails if 5 digits return partnum

if name == 'main': if len(sys.argv) == 2 and sys.argv[1] == '-help': print('Use: split.py [file-to-split target-dir [chunksize]]') else: if len(sys.argv) < 3: interactive = True fromfile = input('File to be split? ') # input if clicked todir = input('Directory to store part files? ') else: interactive = False fromfile, todir = sys.argv[1:3] # args in cmdline if len(sys.argv) == 4: chunksize = int(sys.argv[3]) absfrom, absto = map(os.path.abspath, [fromfile, todir]) print('Splitting', absfrom, 'to', absto, 'by', chunksize)

    try:
        parts = split(fromfile, todir, chunksize)
    except:
        print('Error during split:')
        print(sys.exc_info()[0], sys.exc_info()[1])
    else:
        print('Split finished:', parts, 'parts are in', absto)
    if interactive: input('Press Enter key') # pause if clicked