How to use Python to generate file md5 check value function

Foreword

There is a command in Linux called md5sum, which can generate the md5 value of a file. Under normal circumstances, the result will be recorded in a file for verification. For example, it will be used like this:

[crazyant@localhost PythonMd5]$ more sample_file 
www.crazyant.net
www.51projob.com
[crazyant@localhost PythonMd5]$ md5sum sample_file > sample_file.md5file
[crazyant@localhost PythonMd5]$ more sample_file.md5file 
311d384505e3622ccf85d88930e2b0a0 sample_file
[crazyant@localhost PythonMd5]$ md5sum -c sample_file.md5file 
sample_file: OK

Among them, md5sum -c is used to check whether the generated md5 value is correct.

Use python to generate file md5 values ​​and generate result files that are the same as md5sum results

Python can use hashlib's md5 module to generate md5 check codes for file contents. If you want to generate the same result file as md5sum, you only need to output the MD5 result value and file name in one line, with two spaces in the middle.

Test code:

# -*- encoding:utf-8 -*-
from hashlib import md5
import os
  
def generate_file_md5value(fpath):
 '''以文件路径作为参数，返回对文件md5后的值
 '''
 m = md5()
 # 需要使用二进制格式读取文件内容
 a_file = open(fpath, 'rb') 
 m.update(a_file.read())
 a_file.close()
 return m.hexdigest()
  
def generate_file_md5sumFile(fpath):
 fname = os.path.basename(fpath)
 fpath_md5 = "%s.md5" % fpath
 fout = open(fpath_md5, "w")
 fout.write("%s %s\n" % (generate_file_md5value(fpath), fname.strip()))
 print "generate success, fpath:%s" % fpath_md5
 fout.flush()
 fout.close()
  
if __name__ == "__main__":
 fpath = "/home/users/workbench/PythonMd5/sample_file"
 # 测试一：以文件路径作为参数，获得md5后的字符串
 print generate_file_md5value(fpath)
  
 # 测试二：生成和linux命令：md5sum同样结果的.md5文件
 generate_file_md5sumFile(fpath)

Running result:

[crazyant@localhost PythonMd5]$ python generateMd5file.py
311d384505e3622ccf85d88930e2b0a0
generate success, fpath:/home/crazyant/workbench/PythonMd5/sample_file.md5
[crazyant@localhost PythonMd5]$ md5sum -c sample_file.md5
sample_file: OK

be careful

If the code developed under Windows is directly submitted to Linux for running, the code execution often fails because the newline character under Windows is \r\n but Linux is \n. Generally, a conversion is required.

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