Files

一些基本方法

Ruby中文件操作相关的方法都在File里面，具体如下

  • open - 打开文件
  • close - 关闭文件
  • read - 读取文件内容
  • readline - 读取文件中一行
  • truncate - 截短文件（默认是清空）
  • write - 写入文件
filename = ARGV.first
script = $0

puts "We're going to erase #{filename}."
puts "If you don't want that, hit CTRL-C (^C)."
puts "If you do want that, hit RETURN."

print "? "
STDIN.gets

puts "Opening the file..."
target = File.open(filename, 'w')

puts "Truncating the file.  Goodbye!"
target.truncate(target.size)

puts "Now I'm going to ask you for three lines."

print "line 1: "; line1 = STDIN.gets.chomp()
print "line 2: "; line2 = STDIN.gets.chomp()
print "line 3: "; line3 = STDIN.gets.chomp()

puts "I'm going to write these to the file."

target.write(line1)
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")

puts "And finally, we close it."
target.close()

更多的方法

  • exists? - 文件是否存在
  • zero? - 是否是个空文件
from_file, to_file = ARGV
script = $0

puts "Copying from #{from_file} to #{to_file}"

# we could do these two on one line too, how?
input = File.open(from_file)
indata = input.read()

puts "The input file is #{indata.length} bytes long"

puts "Does the output file exist? #{File.exists? to_file}"
puts "Ready, hit RETURN to continue, CTRL-C to abort."
STDIN.gets

output = File.open(to_file, 'w')
output.write(indata)

puts "Alright, all done."

output.close()
input.close()