How to have the sed output side by side?

Question

I want to have standard output for KEGG pathways of a gene placed side by side no matter how many lines of the KEGG pathways it has. For example, a gene TT123456 is involves in

Answer 1

You could use tr:

tr '\n' '\t' < inputfile

For your input, it'd produce:

Valine, leucine and isoleucine degradation      Histidine metabolism    Ascorbate and aldarate metabolism       Lysine degradation      Glycerolipid metabolism

Using sed:

sed '$!{:a;N;s/\n/\t/;ta}' inputfile