Linux diff command

In this tutorial, I use diff command output on screen. How to compare different line by line in  files. How to compare side by side, color , output do not output common lines with diff command.

What diff command work?

• compare files line by line

For example my topic, I compare line by line in 2 file: file1.txt and file2.txt
The content file1.txt file

[huupv@huupv huuphan.com]$ cat file1.txt
<####################################>
author: huupv
My Blog: www.huuphan.com
Hello everbody!

<####################################>

The content file2.txt file

[huupv@huupv huuphan.com]$ cat file2.txt
<####################################>
author: huupv
My Blog: www.devopsrole.com
Hello everbody!

<####################################>

The default compare line by line with diff comand

[huupv@huupv huuphan.com]$ diff file1.txt file2.txt

The output as below:

3c3
< My Blog: www.huuphan.com
---
> My Blog: www.devopsrole.com

The output number lines with -u option

[huupv@huupv huuphan.com]$ diff -u file1.txt file2.txt

The output as below:

--- file1.txt    2018-06-03 10:44:24.215928386 +0700
+++ file2.txt    2018-06-03 10:45:08.740499854 +0700
@@ -1,6 +1,6 @@
 <####################################>
 author: huupv
-My Blog: www.huuphan.com
+My Blog: www.devopsrole.com
 Hello everbody!

 <####################################>

The output with default color

[huupv@huupv huuphan.com]$ diff -u  --color  file1.txt file2.txt

The output side by side with -y option

[huupv@huupv huuphan.com]$ diff -y file1.txt file2.txt

The output side by side and do not output common lines with -y , --suppress-common-lines option

[huupv@huupv huuphan.com]$ diff -y --suppress-common-lines file1.txt file2.txt

Linux diff command with option in this tutorial

• -y, --side-by-side : output in two columns
• --suppress-common-lines: do not output common lines

Conclusion 

Thought this article, To help you  compare different line by line in files.