[Python编程(第4版)].(Programming.Python.4th.Edition).Mark.Lutz.文字版

else:
name = prefix + line[mlen:-1] # or make new output
print('creating:', name)
output = open(name, 'w')

if name == 'main': unpack(sys.argv[1])

These scripts are fairly basic, and this GUI part of the book assumes you’ve already
scanned the system tools chapters, so we won’t go into their code in depth. Variants
of these scripts appeared in the first edition of this book in 1996; I actually used them
early on in my Python career to bundle files before I could rely on tools like tar and zip
to be present on all the machines I used (and before Python grew tar and zip support
modules in its standard library). Their operation is straightforward—consider these
three text files:

C:\...\PP4E\Gui\ShellGui> type spam.txt

spam

Spam

SPAM

C:\...\PP4E\Gui\ShellGui> type eggs.txt

eggs

C:\...\PP4E\Gui\ShellGui> type ham.txt

h

a

m

When run from the command line, the packer script combines them into a single text
file, and the unpacker extracts them from there; the packer must take care to glob
(expand) filename patterns, because this isn’t done by default in Windows:

C:\...\PP4E\Gui\ShellGui> packer.py packed.txt *.txt

packing: eggs.txt

packing: ham.txt

packing: spam.txt

C:\...\PP4E\Gui\ShellGui> unpacker.py packed.txt

creating: new-eggs.txt

creating: new-ham.txt

creating: new-spam.txt

The result files have a unique name by default (with an added prefix to avoid accidental
overwrites, especially during testing), but you otherwise get back what you packed:

C:\...\PP4E\Gui\ShellGui> type new-spam.txt

spam

Spam

SPAM

C:\...\PP4E\Gui\ShellGui> type packed.txt

::::::::::::::::::::textpak=>eggs.txt

eggs

::::::::::::::::::::textpak=>ham.txt

618 | Chapter 10: GUI Coding Techniques