How to Add or Insert Lines into End of a File in Linux

Let’s suppose you need to insert some data into a large file. Because of its size, it’d take a lot of time to open it in an editor and add it manually. Also, it might be hard to scroll to the end of the file.

# cat file1.txt
Line #1
Line #2
Line #3
Line #4

Append text to end of file using echo command

You need to use the >> to append text to end of file. It is also useful to redirect and append/add line to end of file on Linux or Unix-like system.

echo 'New Line with echo command' >> file1.txt

# echo 'New Line with echo command' >> file1.txt
# cat file1.txt
Line #1
Line #2
Line #3
Line #4
New Line with echo command

Another option is to run command and append output to a file.

# cat /etc/os-release >> os.txt
# cat os.txt
NAME="Ubuntu"
VERSION="20.04.5 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.5 LTS"
...

Append text to end of file using sedcommand

Run the following command to insert the line “New Line with sed command” at the end of the file file1.txt.

sed -i -e '$a New Line with sed command' file1.txt

The $matches the last line. And the a is the append command

# sed -i -e '$a New Line with sed command' file1.txt
# cat file1.txt
Line #1
Line #2
Line #3
Line #4
New Line with echo command
New Line with sed command