how to concatenate lines into one string

Question

I have a function in bash that outputs a bunch of lines to stdout. I want to combine them into a single line with some delimiter between them.

Before:

one 
two 
three 

After:

one:two:three   

What is an easy way to do this?

Answer 1

Use paste

$ echo -e 'one\ntwo\nthree' | paste -s -d':'
one:two:three