In the vi editor, if you want to add the text before some keywords in the multiple lines,  you can use this awk script.

For example: I have this file name called “/root/temp” and I want to add the word “sddl” in front of the words “Device: -r”.  I wrote my awk script like this:

awk ‘ {
if ($0 ~ /^\sddl/)
print “Device:-r”$0
else
print $0

} ‘ /root/temp

If you run the script, you will see the output and then you can redirect the output to a new file.