MD5 Verify that two files are the same

1. Introduction

MD5 algorithm is often used to verify the integrity of network file transmission, to prevent files from being tampered with. MD5 full name is the digest to the algorithm (Message-digest algorithm 5), this algorithm for arbitrary length of information in a bitwise calculation, resulting in a binary length of 128 digits (hexadecimal length is 32 bits) of the "fingerprint" (or "Digest to"), The possibility that different documents produce the same report digest is very, very small.
On Linux or UNIX, md5sum is the tool that is used to compute and validate the document digest. In general, the installation of Linux, there will be md5sum this tool, directly in the command line terminal to run directly.

2. Command Format

md5sum [OPTION] ... [FILE] ...

3. Command Options

-B or--binary: treat the input file as a binary file.
-T or--text: treat the entered file as a text file (default).
-C or--check: used to read MD5 information from a file to check the consistency of the file. (See info)
--status: This option is used in conjunction with a check, which does not output at check time, but rather indicates the result of the check based on the return value.
-W or--warn: When checking, check the input of the MD5 information and no illegal lines, if there is output the appropriate information.

4. Examples

(1) The MD5 value of a file is produced, as shown in the following figure

(2) Check if two files are the same, you can compare the MD5 value of two files.

(3) To judge whether a file is modified by MD5

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