Add to every end of line in notepad++

I have long text file

gallery-dl -g -i w4b027.txt > 
gallery-dl -g -i a4b028.txt > 
gallery-dl -g -i b4b029.txt > 
gallery-dl -g -i c4b030.txt > 
gallery-dl -g -i d4b031.txt > 
gallery-dl -g -i w4b032.txt > 
gallery-dl -g -i w4b033.txt > 
gallery-dl -g -i w4b034.txt > 
gallery-dl -g -i w4b035.txt > 
gallery-dl -g -i w4b036.txt > 
gallery-dl -g -i w4b037.txt > 
gallery-dl -g -i w4b038.txt > 
gallery-dl -g -i w4b039.txt > 
gallery-dl -g -i w4b040.txt >

I want to make it

gallery-dl -g -i a4b027.txt > a4b027x.txt
gallery-dl -g -i b4b028.txt > b4b028x.txt
gallery-dl -g -i c4b029.txt > ...

First text file to 2nd text file with sufix "x".