import os
import os.path

def splitpath(path):
	"returns list of all path components"

	L = [path]
	while True:
		path = L.pop(0)	
		if not path:
			return L
		elif path == os.path.sep:
			return [path] + L
		else:
			L = list(os.path.split(path)) + L


def realpath(path):
	current_dir = []

	L = splitpath(os.path.abspath(path))
	while len(L):
		#print(L)
		filename = L.pop(0)
		#print('filename', filename)

		if filename == '.':
			continue
		elif filename == '..':
			current_dir.pop()
		else:
			current_dir.append(filename)
		
		cwd = os.path.sep.join(current_dir)
		#print("cwd", cwd)

		if os.path.islink(cwd):
			tmp = os.readlink(cwd)
			if os.path.isabs(tmp):
				current_dir = splitpath(tmp)
			else:
				L = splitpath(tmp) + L
				current_dir.pop()

	return os.path.join(*current_dir)


import sys
path = 'zlink'
path = sys.argv[1]

os.system("readlink -f %s" % path)
print("py ", os.path.realpath(path))
print("=> ", realpath(path))