1. random-cmd gives a list of values (one per line) 

yoswink@krystal $ random-cmd
foo
fee
fuu

2. I put the result into a bash variable and try to make an expansion but seems not to work

yoswink@krystal $ { foo=$(random-cmd) ; echo ${foo// /whatIwantToPut} }
foo fee fuu

Probably is some kind of control char (end-of-line?) between the items, any idea about how to replace it?