Ruby | 配列で最初の要素だけを削除する ( 2行目以降を全て得る ) ref: http://qiita.com/Yinaura/items/129f702553c5b6027bfb

file0.txt

['A','B','C','D','E'].drop(1)

# => ["B", "C", "D", "E"]

file1.txt

['A','B','C','D','E'].shift

=> "A"

file2.txt

['A','B','C','D','E'].shift!
# => NoMethodError: undefined method `shift!' for ["A", "B", "C", "D", "E"]:Array

file3.txt

alphabets = ['A','B','C','D','E'] 

alphabets.shift

alphabets 

# =>  ["B", "C", "D", "E"]

file4.txt

['A','B','C','D','E'][1..-1]

# => ["B", "C", "D", "E"]