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Learning Python
book

Learning Python

by Mark Lutz, David Ascher
April 1999
Beginner content levelBeginner
384 pages
11h 15m
English
O'Reilly Media, Inc.
Content preview from Learning Python
  1. Redirecting stdout. This is simple: all you have to do is to replace the first line with:

    import fileinput, sys, string               # no change here
    sys.stdout = open(sys.argv[-1], 'w')        # open the output file
    del sys.argv[-1]                            # we've dealt with this argument
    ...                                         # continue as before
  2. Writing a simple shell. Mostly, the following script, which implements the Unix set of commands (well, some of them) should be self-explanatory. Note that we’ve only put a “help” message for the ls command, but there should be one for all the other commands as well:

    import cmd, os, string, sys, shutil class UnixShell(cmd.Cmd): def do_EOF(self, line): """ The do_EOF command is called when the user presses Ctrl-D (unix) or Ctrl-Z (PC). """ sys.exit() def help_ls(self): print "ls <directory>: list the contents of the specified directory" print " (current directory used by default)" def do_ls(self, line): # 'ls' by itself means 'list current directory' if line == '': dirs = [os.curdir] else: dirs = string.split(line) for dirname in dirs: print 'Listing of %s:' % dirname print string.join(os.listdir(dirname), '\n') def do_cd(self, dirname): # 'cd' by itself means 'go home' if dirname == '': dirname = os.environ['HOME'] os.chdir(dirname) def do_mkdir(self, dirname): os.mkdir(dirname) def do_cp(self, line): words = string.split(line) sourcefiles,target = words[:-1], words[-1] # target could be a dir for sourcefile in sourcefiles: shutil.copy(sourcefile, target) def do_mv(self, line): source, target = string.split(line) ...
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Publisher Resources

ISBN: 1565924649Supplemental ContentCatalog PageErrata