#!/usr/bin/python#Author: lxw0109#Date: 20140719#Usage: List contents of directories in a tree-like format.import osimport sysdef tree(directory, count):    if os.path.isdir(directory):        print((count + 1) * "|   " + "|---" + os.path.basename(directory))        # Get the file/directory list in ‘dir‘        dirFormat = os.listdir(directory)        dirFormat.sort()        for dirItem in dirFormat:            #absPath = os.path.abspath(dirItem)                #NO: On most platforms, this is equivalent to calling the function normpath() as follows:            #normpath(join(os.getcwd(), path))            absPath = directory + os.sep + dirItem            tree(absPath, count + 1)    else:        print((count + 1) * "|   "+ "|---" + os.path.basename(directory))def main():    #print(sys.argv)    #NOTE: sys.argv is a list.    if len(sys.argv) != 2:        print("Usage: tree DirectoryName")        sys.exit(0)    #directory = "/home/lxw/Documents/Programing"    directory = sys.argv[1]    #Get rid of the ‘/‘ at the end.    if directory.endswith(os.sep):        directory = directory[:-1]    #turn Relative Path / Absolute Path into Absolute Path.    if directory[0] != ‘/‘:        #print("RELATIVE: " + directory[0])        directory = os.getcwd() + os.sep + directory        #print("direcotry: " + directory)    #count = directory.count(os.sep)    tree(directory, -1)if __name__ == "__main__":    main()