How to Append / Insert Multiple New Line in a File Using Shell Script?

Insert Multiple New Line in a File Using Shell Script?

Do you want to insert multiple lines below of a specific line sed command will help us with different cases,

For example few lines saved in a file name of linuxfaq.txt that contain

but i would like to add three lines one by one "red, green, blue" next line of colors

Note : -i specified that save the changes in file

sed -i "/colors/ared\ngreen\nblue" linuxfaq.txt

Once you have executed that command output will be
 
If are you Passing String by Variable,
 

sed -i "/colors/ared\ngreen\n$color" linuxfaq.txt

How you can insert lines from a file.
 

sed '/colors/r toadd.txt' linuxfaq.txt

Do you want to append a string at the end of specific line?

For example,
 
Need to add a "linux" word at end of "ext4"

sed 's/ext4/& linux/' linuxfaq.txt