The stream editor (sed) is a very popular non-interactive stream editor. Normally, whenever we edit files using the vi editor, we need to open the file using the vi command, then we interact with the file to see the content of the file on screen, then edit it, and then save the file. Using sed, we can type commands on the command line and sed will make the changes to the text file. sed is a non-destructive editor. sed makes the changes to the file and displays the content on screen. If we want to save the changed file, then we need to redirect the output of sed to the file.
The procedure to install sed is shown here.
For Ubuntu or any Debian-based distributions, enter the following command:
$ apt-get install ...