Hey
Here print which is an list operator prints the evaluated value in first case so prints the value 20, but in second case prints the list of values, since its not evaluating.
see this example
print reverse join ' ', q/hai how are you/
print join ' ', q/hai how are you/
Your argument and code are both very fuzzy, and it is unclear what your point is.
It looks like you are attempting to join a scalar value created by the q// operator. join of a scalar is a no-op. Since the result is a scalar, the reverse is a no-op also.
What you may have been tryng to do is:
perl -e "print reverse split ' ', q/hai how are you/"
#PRINTS: youarehowhai
..."I don't know what the facts are but somebody's certainly going to sit down with him and find out what he knows that they may not know, and make sure he knows what they know that he may not know, and that's a good thing. I think it's a very constructive exchange," --Donald Rumsfeld