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  • Linux md5sum 命令

    Linux md5sum 命令


     

    通过 Linux 的 md5sum 命令,可以对指定的文件,计算出唯一的一个MD5值(128bit)。

    通过比较文件前后的MD5值,可以判断文件是否发生变化(是否被修改过)。


    1、md5sum 命令使用方式(通过md5sum --help查看):

    Usage: md5sum [OPTION]... [FILE]...
    Print or check MD5 (128-bit) checksums.
    With no FILE, or when FILE is -, read standard input.
    
      -b, --binary         read in binary mode
      -c, --check          read MD5 sums from the FILEs and check them
          --tag            create a BSD-style checksum
      -t, --text           read in text mode (default)
      Note: There is no difference between binary and text mode option on GNU system.
    
    The following four options are useful only when verifying checksums:
          --quiet          don't print OK for each successfully verified file
          --status         don't output anything, status code shows success
          --strict         exit non-zero for improperly formatted checksum lines
      -w, --warn           warn about improperly formatted checksum lines
    
          --help     display this help and exit
          --version  output version information and exit
    
    The sums are computed as described in RFC 1321.  When checking, the input
    should be a former output of this program.  The default mode is to print
    a line with checksum, a character indicating input mode ('*' for binary,
    space for text), and name for each FILE.
    
    GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
    For complete documentation, run: info coreutils 'md5sum invocation'

    2、计算一个文件的 MD5 值

    1)新建一个文件test.txt,内容为 Hello, md5sum.

    使用如下命令,生成改文件对应的 MD5 值

    md5sum test.txt > md5.out

    2)此时会在当前目录下看到生成的 md5.out 文件

    3)查看改文件对应的 MD5 值

    cat md5.out

    4)使用如下命令,比较文件的 MD5 值是否发生变化

    md5sum -c md5.out

    5)当修改test.txt 文件,增加 Modify 单词,再次对比 MD5 值,会发现不一致

    6)BSD格式查看 MD5 值

    md5sum --tag md5.out 

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  • 原文地址:https://www.cnblogs.com/miracle-luna/p/11967246.html
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