What is sum Linux command?

The Linux sum command calculates and prints the checksum and block counts of a file. It can be used to verify the integrity of files and detect any changes or corruption.

sum Syntax:

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

sum Options:

Option	Description
-s	Print only the sum of data
-r	Print in reverse order
-0	End each output line with ASCII NUL

Caution

Avoid using the sum command for critical operations as it is mainly used for checking data integrity rather than general purpose file manipulation.

Parameters:

Parameter	Description
FILE	Specify the paths to the files to sum

sum Command Usage Examples:

Check the Checksum of a File

sum file.txt

Calculates and displays the checksum of the file “file.txt”.

Verify Multiple Files Checksum

sum file1.txt file2.txt file3.txt

Calculates and displays the checksum of multiple files “file1.txt”, “file2.txt”, and “file3.txt”.

Compare Checksums between Two Files

sum file1.txt file2.txt

Calculates and displays the checksums of “file1.txt” and “file2.txt” for comparison.

Redirect Sum Output to a File

sum file.txt > checksum.txt

Calculates and saves the checksum of “file.txt” in a separate file named “checksum.txt”.

Display Checksum in Binary/Hexadecimal Form

sum -r file.txt

Calculates and displays the checksum of “file.txt” in binary and hexadecimal form.

Tip

When using the sum command in Linux, remember that it is commonly used to calculate checksums and check if files are identical. It is helpful for verifying file integrity and security.

How do I use sum in Linux?

To use the sum command in bash, execute the following command:

sum file.txt

How can I output the checksum in a specific format with sum?

To output the checksum in a specific format, use the following command:

sum --format=null file.txt

How can I display the help information for sum command?

To display the help information for the sum command, use the following command:

sum --help

How do I verify the integrity of a file using sum?

To verify the integrity of a file using sum, execute the following command:

sum -c checksum.txt

How to calculate the checksum of multiple files with sum?

To calculate the checksum of multiple files, use the following command:

sum file1.txt file2.txt

Can I ignore warnings when using sum in Linux?

To ignore warnings when using sum, you can use the -w flag in the command. For example:

sum -w file.txt

How to specify a different hashing algorithm with sum?

To specify a different hashing algorithm, use the -a option in the command. For example, to use SHA256, run:

sum -a SHA256 file.txt

Is there a way to only display the checksum without the filename using sum?

To display only the checksum without the filename, use the -t option in the command. For example:

sum -t file.txt

Applications of the sum command

• Checking for changes in files
• Verifying data integrity