How to use the command diffstat (with examples)

Diffstat is a command-line tool that creates a histogram from the output of the diff command. It provides a visual representation of the changes between two files. The diffstat command is useful for quickly understanding the differences between two versions of a file or a folder.

Use case 1: Display changes in a histogram

Code:

diff file1 file2 | diffstat

Motivation: You have made some changes to a file and want to see a high-level overview of the differences between the original file (file1) and the modified file (file2). By using diffstat, you can quickly identify the areas that have been changed.

Explanation:

• diff: The diff command compares two files line by line and outputs the differences.
• file1 file2: These are the two files that you want to compare.
• | (pipe operator): This redirects the output of the diff command to the diffstat command.
• diffstat: The diffstat command takes the output of the diff command and creates a visual representation of the changes in the form of a histogram.

Example output:

 file1 |   46 +++
 file2 |   31 +++
 2 files changed, 77 insertions(+)

This output indicates that there have been 46 lines added to file1 and 31 lines added to file2, resulting in a total of 77 insertions.

Use case 2: Display inserted, deleted, and modified changes as a table

Code:

diff file1 file2 | diffstat -t

Motivation: You want to view the changes between two files in a more detailed manner. By using the -t option with diffstat, you can get a table representation of the inserted, deleted, and modified lines.

Explanation:

• diff file1 file2: This compares two files and outputs the differences.
• | (pipe operator): This redirects the output of the diff command to the diffstat command.
• diffstat: The diffstat command takes the output of the diff command.
• -t: This option instructs diffstat to display the changes as a table.

Example output:

 insertions | deletions | file
   ---------+-----------+------
         46 |         0 | file1
         31 |         0 | file2

The output above shows that there have been 46 insertions and 0 deletions in file1, and 31 insertions and 0 deletions in file2. This table provides a clear overview of the changes made to the files.

Conclusion:

The diffstat command is a powerful tool for visualizing the differences between two versions of a file or a folder. By using diffstat, you can quickly identify the changes made, whether it’s by viewing a histogram or a table representation. This can be particularly useful when reviewing code changes or tracking modifications in files over time.