Joining two consecutive lines using awk or sed

Question

How would I join two lines using awk or sed?

for e.g.:

I have data that looks like this:

abcd
joinabcd
efgh
joinefgh
ijkl
j         


        

Answer 1

You can use printf with a ternary:

    awk '{printf (NR%2==0) ? $0 "\n" : $0}'