git clone https://github.com/knrredhelmet/anew.git
cd anew
go build anew.go
Here, a file called things.txt contains a list of numbers. newthings.txt contains a second
list of numbers, some of which appear in things.txt and some of which do not. anew is used
to append the latter to things.txt.
▶ cat things.txt
Zero
One
Two
▶ cat newthings.txt
One
Two
Three
Four
▶ cat newthings.txt | anew things.txt
Three
Four
▶ cat things.txt
Zero
One
Two
Three
Four
cat newthings.txt | anew things.txt -o added-lines.txt
▶ cat added-lines.txt
Three
Four