Ruby File

Contents

• Directory
• File

Directory

Open directory

open

dir = Dir.open("/usr/local/bin")
dir.each{|file| puts file}
dir.close

each is to enumerate files in dir
If you use block method, you don’t need close method

Dir.open("/usr/local/bin"){|dir| puts dir.path}  # path : Directory path

Methods

Examples

Dir.pwd
Dir.chdir("/usr/local")   #=> 0 Success
Dir.mkdir("/tmp/homuhomu") #=> 0 Success
Dir.rmdir("/tmp/homuhomu") #=> 0 Success

File

File class

Read file

file = File.open("Read.me")
file.read    # Read all data
file.close

Set number of byte

file = File.open("README.md")
file.read(100)  # 100 bytes
file.close

Block

File.open('README.md') { |file| file.read }

Read per line

gets

file = File.new("README.md", "r")
while (line = file.gets)
    puts "#{line}"
end
file.close

Block

File.open("README.md", "r") do |file|
    while (line = file.gets)
        puts "#{line}"
    end
end

Exception handle

mode

write

File.open('new-file', "w"){|file| file.write("Hello World!") }

File attr

File.mtime('README.md')
File.open('README'){|file| file.mtime}

If you use “.” as basename, you can get only file name.

FileTest module

File.directory?('/usr/local')       #=> true
File.directory?('/usr/local/bin/zsh')   #=> false

UNIX command?

Get file attr

File.chmod(0644, 'README')

Set latest access time and update time

File.utime(Time.now, Time.now, 'FIXME')

Convert path to absolute path

File.expand_path('README')

Remove file, rename

File.delete('README.md')
File.rename('README', 'FIXME')

Truncate file
truncate file defined byte

File.truncate('FIXME', 0)

Lock

File.open('README', "w"){|file| file.flock(File::LOCK_EX)}

fileutil

Basic library of IO.
FileUtils is used like UNIX command
You need to add require

require 'fileutils'

Change directory(cd), current directory(pwd)

FileUtils.cd(dir, options={})
FileUtils.pwd

Copy(cp, copy, cp_r)

FileUtils.cp(src, dest, options={})
FileUtils.copy(src, dest, options={})

cp_r

FileUtils.cp_r(src, dst, options={})

recursive, you can use directory as src.

Move(mv/move)

FileUtils.mv(src, dist, options={})
FileUtils.move(src, dist, options={})

Remove(rm/remove)

FileUtils.rm(list, options={})
FileUtils.remove(list, options ={})

rmdir

rm_r, rm_rf

FileUtils.rm_r(list, options={})
FileUtils.rm_rf(list, options={})

touch

FileUtils.touch(list, options={})

mkdir

FileUtils.mkdir(list, options={})
FileUtils.mkdir_p(list, options={})

chown, chmod

FileUtils.chown(user, group, list, options={})
FileUtils.chmod(mode, list, options ={})

ln, ln_s/symlink

FileUtils.ln_s(src, dest, option ={})
FileUtils.symlink(src, dest, options={})