sum command in Linux is used to find checksum and count the blocks in a file. Basically, this command is used to show the checksum and block count for each specified file. When no file is specified then it will read the standard input.

Syntax:

sum [OPTION]... [FILE]...

Example: It will ask for the input of the file we want to calculate the checksum. In the following example, we are calculating the checksum for myfile.txt.

Options:

• sum -r: This option will use BSD sum algorithm, use 1K blocks.

  Example:

  sum -r myfile.txt

  

• sum -s: This option will use System V sum algorithm, use 512 bytes blocks.

  Example:

  sum -s myfile.txt 

  

• sum –help : This option displays the help text and exit.

  sum --help

  

• sum –version : This option will show the version information and exit.

  sum --version