python3 读写文件换行符的方法

open(dirpath + "\\" + file, mode = "r+", encoding = "gbk", newline = "")

import os
import re
os.chdir(r"E:\code")
s = os.walk(".")
pattern = re.compile(r"\s-c\s")
for dirpath, dirnames, filenames in s:
	for file in filenames:
		if file.endswith(".mak") or "makefile" in file: #部分以 .mak 结尾，部分以makefile命名
			print(file)
			with open(dirpath + "\\" + file, mode = "r+", encoding = "gbk", newline = "") as f: #newline为空串表示换行符不转换
				try: #编码问题造成的异常
					lines = f.readlines() #一次读取所有的行到内存
					f.seek(0)    #回到文件起始处
					for line in lines:
						#newline = line.replace(" -c "," -g -c ")
						newline= re.sub(pattern, " -g -c ", line)
						f.write(newline)
				except ValueError:
					f.close()
					with open(dirpath + "\\" + file, mode = "r+", encoding = "utf-8", newline = "") as fnew:
						try: 
							lines = fnew.readlines() 
							fnew.seek(0)    
							for line in lines:
								#newline = line.replace(" -c "," -g -c ")
								newline= re.sub(pattern, " -g -c ", line)
								fnew.write(newline)
						except ValueError:
							print("*************** " + dirpath + "\\" + file) #打印utf-8 和 gbk 之外编码的文件名