Ruby always runs while the first time

You can combine the begin clause with the while qualifier.

 begin
  puts1
end while false

However, this notation is not recommended in the Ruby Style Guide. Use the loop/break combination instead.

loop do
  puts1
  breakless false
end

The while qualifier behaves differently depending on whether or not it is combined with the begin clause, so it is a cause of misunderstanding.

 puts1 while false# Do nothing

begin;puts1;end while false#puts1 is called

 begin
  puts1
end while false

How about