use str

edit:add-var grawlix~ {|@argv|
      var @chars  = (str:split '' '#$%&*+=^~£§¶±÷≠Ω√∆◊')
      var nbChars = (count $chars)
      var length  = (shuf -i 4-7 -n 1)
      var graw    = []

      range $length | each {|_|
        var ci    = (shuf -i 1-$nbChars -n 1)
        set @graw = $@graw $chars[(- $ci 1)]
      }

      set @graw = $@graw '!'

      echo (str:join '' $graw)
}