cheat sheets.

Any delimiter is allowed, so for instance %w(...), %w[...], %w{...} and %w!...!
are all equal.

% "double-quoted string (without qualifier)"
  >> %(some #{foo} string)
  => "some bar string"

%Q "double-quoted string"
  >> %Q(some #{foo} string)
  => "some bar string"

%q 'single-quoted string'
  >> %q(some #{foo} string)
  => 'some \#{foo} string'

%W "double-quoted words"
  >> %W(some #{foo} bar)
  => ["some", "bar", "bar"]

%w 'single-quoted words'
  >> %w(some #{foo} bar)
  => ['some', '\#{foo}', 'bar']

%x backtick execute
  >> %x(ls)
  == `ls`

%r regular expression
  >> %r(/usr/bin/)
  == /\/usr\/bin\//

%s symbol
  >> %s(some symbol)
  => :"some symbol"