一、新建文件
代碼如下:
    f=File.new(File.join("C:","Test.txt"), "w+")
    f.puts("I am Jack")
    f.puts("Hello World")

文件模式
"r" ：Read-only. Starts at beginning of file (default mode).
"r+" ：Read-write. Starts at beginning of file.
"w" ：Write-only. Truncates existing file to zero length or creates a new file for writing.
"w+" ：Read-write. Truncates existing file to zero length or creates a new file for reading and writing.
"a" ：Write-only. Starts at end of file if file exists; otherwise, creates a new file for writing.
"a+" ：Read-write. Starts at end of file if file exists; otherwise, creates a new file for reading and writing.
"b" ：(DOS/Windows only.) Binary file mode. May appear with any of the key letters listed above

二、讀取文件
代碼如下:
    file=File.open(File.join("C:","Test.txt"),"r")
    file.each { |line| print "#{file.lineno}.", line }
    file.close

三、新建、刪除、重命名文件
代碼如下:
    File.new( "books.txt", "w" )
    File.rename( "books.txt", "chaps.txt" )
    File.delete( "chaps.txt" )

四、目錄操作
1     創建目錄
代碼如下:
    Dir.mkdir("c:/testdir")
     #刪除目錄
     Dir.rmdir("c:/testdir")
     #查詢目錄里的文件
     p Dir.entries(File.join("C:","Ruby")).join(' ')
     #遍歷目錄
     Dir.entries(File.join("C:","Ruby")).each {
          |e| puts e
    }

1、ARGV and ARGF
代碼如下:
ARGV
    ARGV << "cnblogslink.txt"
    #The gets method is a Kernel method that gets lines from ARGV
    print while gets
    p ARGV.class

ARGF
    while line = ARGF.gets
     print line
    end

2、文件信息查詢
代碼如下:
    #文件是否存在
    p File::exists?( "cnblogslink.txt" ) # => true
    #是否是文件
    p File.file?( "cnblogslink.txt" ) # => true
    #是否是目錄
    p File::directory?( "c:/ruby" ) # => true
    p File::directory?( "cnblogslink.txt" ) # => false
    #文件權限
    p File.readable?( "cnblogslink.txt" ) # => true
    p File.writable?( "cnblogslink.txt" ) # => true