Adding a Line in Middle of File using Linux command

Sometimes we need to insert a line at middle of the existing file. You can add line at specific line number using Linux command line or shell scripts.

In this tutorial, we will discuss about adding a text line at middle of file as specific line number.

Let’s have an example, I have a text file named file1.txt with following content:

cat file1.txt 

this is line one
this is line two
this is line three

Now I have to insert text “HelloWorld” at the line number 3. To do this run the following command.

sed -i '3iHelloWorld' file1.txt 

Details of Parameters:

• sed: is the command itself.
• -i: : Update content in same file.
• 3: line number where new line will be inserted.
• i: parameter, which told sed to insert line.
• HelloWorld: text to be added.
• file1.txt: is the file in which new line need to add.

Above command will insert the content in file1.txt at line number 3. Let’s check the content of the file:

cat file1.txt 

this is line one
this is line two
HelloWorld
this is line three