File and Dir

Batch_rename.rb

#当你把照相机接入电脑时，照片文件夹为F盘。下面的程序对照片进行批量重命名。

pic_names = Dir['F:/**/*.{JPG,jpg}']
puts 'What would you like to call this batch?'
batch_name = gets.chomp
puts
print "Downloading #{pic_names.length} files: "
pic_number = 1                   #这是计数器，我们从1开始计数
pic_names.each do |name|
  print '.'                        # 这是进度条.
  new_name = if pic_number < 10
    "batch_name0#{pic_number}.jpg"
  else
    "batch_name#{pic_number}.jpg"
  end
  File.rename name, new_name
  pic_number = pic_number + 1     #计数器增量
end

Dir.rb

#搜索当前文件夹中所有后缀为.txt的文件
>> Dir['*.txt']
=> ["DatasGadgets.txt", "JiaQing.txt", "mybook.txt", "myfriends.txt"]
#搜索当前文件夹中所有后缀为.txt或.yaml的文件
>> Dir['*.{txt,yaml}']
=> ["DatasGadgets.txt", "JiaQing.txt", "mybook.txt", "myfriends.txt", "tree.yaml"]
#搜索当前文件夹及其所有子文件夹中所有后缀为.txt的文件
>> Dir['**/*.txt']
=> ["DatasGadgets.txt", "JiaQing.txt", "louis/jquery/chapter10/buttons/options.txt", "louis/jquery/chapter4/dvds/movies.txt",...]

#pwd和chdir的方法
>> Dir.pwd
=> "/home/Louis"
>> Dir.chdir 'louis'
=> 0
>> Dir.pwd
=> "/home/Louis/louis"
>> Dir.chdir '..'   #返回上一级文件夹
=> 0
>> Dir.pwd
=> "/home/Louis"

#把chdir和Dir[]一起使用。
>> Dir.chdir 'louis/note' do
?> puts Dir['*.txt']
>> end
e-textediter的使用.txt
E-TextEditor快捷键.txt
gem_log.txt
git.txt
programming_art.txt
yuming.txt

file.rb

#File.open is how you open a file. It creates the file object,
#calls it f , runs all the code until it gets to the end, and then closes the file.

#save and load
>> filename = 'mybook.txt'
=> "mybook.txt"
>> test_string = 'This is my ruby book: ' + 'Programming ruby'
=> "This is my ruby book: Programming ruby"
#‘w'表示写入文件
>> File.open filename, 'w' do |f|
?> f.write test_string
>> end
#读取文件内容
>> read_string = File.read filename
=> "This is my ruby book: Programming ruby"

set_up.rb

#!/usr/bin/env ruby
require 'fileutils'
 
# copy config files
Dir['config/examples/*'].each do |source|
  destination = "config/#{File.basename(source)}"
  unless File.exist? destination
    FileUtils.cp(source, destination)
    puts "Generated #{destination}"
  end
end

# run rake setup tasks
system "rake gems:install db:create:all"
system "rake db:migrate --trace"

Well, that’s all well and good if all you want to save and load are single strings. But what if you wanted to save an array of strings? Or an array of integers and floats? 这就需要YAML了