class File
Constants
- PTOOLS_VERSION
The version of the ptools library.
Public Class Methods
Returns whether or not file
is a binary non-image file, i.e. executable, shared object, etc.
Internally this method simply looks for a double null sequence. This will work for the vast majority of cases, but it is not guaranteed to be absolutely accurate.
Example:
File.binary?('somefile.exe') # => true File.binary?('somefile.txt') # => false
# File lib/ptools.rb, line 70 def self.binary?(file) return false if File.stat(file).zero? return false if image?(file) return false if check_bom?(file) bytes = File.stat(file).blksize bytes = 4096 if bytes > 4096 (File.read(file, bytes) || '').include?("\u0000\u0000") end
Is the file a bitmap file?
# File lib/ptools.rb, line 424 def self.bmp?(file) data = File.read(file, 6, nil, :encoding => 'binary') data[0,2] == 'BM' && File.size(file) == data[2,4].unpack('i').first end
Is the file a gif?
# File lib/ptools.rb, line 443 def self.gif?(file) %w[GIF89a GIF97a].include?(File.read(file, 6)) end
In block form, yields the first num_lines
from filename
. In non-block form, returns an Array of num_lines
Examples:
# Return an array File.head('somefile.txt') # => ['This is line1', 'This is line2', ...] # Use a block File.head('somefile.txt'){ |line| puts line }
# File lib/ptools.rb, line 203 def self.head(filename, num_lines = 10) a = [] File.foreach(filename) do |line| break if num_lines <= 0 num_lines -= 1 if block_given? yield line else a << line end end a.empty? ? nil : a # Return nil in block form end
Is the file an ico file?
# File lib/ptools.rb, line 466 def self.ico?(file) ["\000\000\001\000", "\000\000\002\000"].include?(File.read(file, 4, nil, :encoding => 'binary')) end
Returns whether or not the file is an image. Only JPEG, PNG, BMP, GIF, and ICO are checked against.
This reads and checks the first few bytes of the file. For a version that is more robust, but which depends on a 3rd party C library (and is difficult to build on MS Windows), see the ‘filemagic’ library.
By default the filename extension is also checked. You can disable this by passing false as the second argument, in which case only the contents are checked.
Examples:
File.image?('somefile.jpg') # => true File.image?('somefile.txt') # => false
# File lib/ptools.rb, line 50 def self.image?(file, check_file_extension: true) bool = bmp?(file) || jpg?(file) || png?(file) || gif?(file) || tiff?(file) || ico?(file) bool &&= IMAGE_EXT.include?(File.extname(file).downcase) if check_file_extension bool end
Is the file a jpeg file?
# File lib/ptools.rb, line 431 def self.jpg?(file) File.read(file, 10, nil, :encoding => 'binary') == "\377\330\377\340\000\020JFIF".force_encoding(Encoding::BINARY) end
Converts a text file from one OS platform format to another, ala ‘dos2unix’. The possible values for platform
include:
-
MS Windows -> dos, windows, win32, mswin
-
Unix/BSD -> unix, linux, bsd, osx, darwin, sunos, solaris
-
Mac -> mac, macintosh, apple
You may also specify ‘local’, in which case your CONFIG value will be used. This is the default.
Note that this method is only valid for an ftype of “file”. Otherwise a TypeError will be raised. If an invalid format value is received, an ArgumentError is raised.
# File lib/ptools.rb, line 283 def self.nl_convert(old_file, new_file = old_file, platform = 'local') raise ArgumentError, 'Only valid for plain text files' unless File::Stat.new(old_file).file? format = nl_for_platform(platform) if old_file == new_file require 'tempfile' temp_name = Time.new.strftime('%Y%m%d%H%M%S') nf = Tempfile.new("ruby_temp_#{temp_name}") else nf = File.new(new_file, 'w') end begin nf.open if old_file == new_file File.foreach(old_file) do |line| line.chomp! nf.print("#{line}#{format}") end ensure nf.close if nf && !nf.closed? if old_file == new_file require 'fileutils' File.delete(old_file) FileUtils.mv(nf.path, old_file) end end self end
Returns the newline characters for the given platform.
# File lib/ptools.rb, line 407 def self.nl_for_platform(platform) platform = RbConfig::CONFIG['host_os'] if platform == 'local' case platform when /dos|windows|win32|mswin|mingw/i "\cM\cJ" when /unix|linux|bsd|cygwin|osx|darwin|solaris|sunos/i "\cJ" when /mac|apple|macintosh/i "\cM" else raise ArgumentError, 'Invalid platform string' end end
Is the file a png file?
# File lib/ptools.rb, line 437 def self.png?(file) File.read(file, 4, nil, :encoding => 'binary') == "\211PNG".force_encoding(Encoding::BINARY) end
Returns whether or not file
is a sparse file.
A sparse file is a any file where its size is greater than the number of 512k blocks it consumes, i.e. its apparent and actual file size is not the same.
See en.wikipedia.org/wiki/Sparse_file for more information.
# File lib/ptools.rb, line 383 def self.sparse?(file) stats = File.stat(file) stats.size > stats.blocks * 512 end
In block form, yields the last num_lines
of file filename
. In non-block form, it returns the lines as an array.
Example:
File.tail('somefile.txt') # => ['This is line7', 'This is line8', ...]
If you’re looking for tail -f functionality, please use the file-tail gem instead.
# File lib/ptools.rb, line 234 def self.tail(filename, num_lines = 10, &block) tail_size = 2**16 # 64k chunks # MS Windows gets unhappy if you try to seek backwards past the # end of the file, so we have some extra checks here and later. file_size = File.size(filename) read_bytes = file_size % tail_size read_bytes = tail_size if read_bytes == 0 line_sep = File::ALT_SEPARATOR ? "\r\n" : "\n" buf = '' # Open in binary mode to ensure line endings aren't converted. File.open(filename, 'rb') do |fh| position = file_size - read_bytes # Set the starting read position # Loop until we have the lines or run out of file while buf.scan(line_sep).size <= num_lines and position >= 0 fh.seek(position, IO::SEEK_SET) buf = fh.read(read_bytes) + buf read_bytes = tail_size position -= read_bytes end end lines = buf.split(line_sep).pop(num_lines) if block_given? lines.each(&block) else lines end end
Is the file a tiff?
# File lib/ptools.rb, line 449 def self.tiff?(file) return false if File.size(file) < 12 bytes = File.read(file, 4) # II is Intel, MM is Motorola return false if bytes[0..1] != 'II' && bytes[0..1] != 'MM' return false if bytes[0..1] == 'II' && bytes[2..3].ord != 42 return false if bytes[0..1] == 'MM' && bytes[2..3].reverse.ord != 42 true end
Changes the access and modification time if present, or creates a 0 byte file filename
if it doesn’t already exist.
# File lib/ptools.rb, line 317 def self.touch(filename) if File.exist?(filename) time = Time.now File.utime(time, time, filename) else File.open(filename, 'w'){} end self end
With no arguments, returns a four element array consisting of the number of bytes, characters, words and lines in filename, respectively.
Valid options are ‘bytes’, ‘characters’ (or just ‘chars’), ‘words’ and ‘lines’.
# File lib/ptools.rb, line 333 def self.wc(filename, option = 'all') option.downcase! valid = %w[all bytes characters chars lines words] raise ArgumentError, "Invalid option: '#{option}'" unless valid.include?(option) n = 0 if option == 'lines' File.foreach(filename){ n += 1 } n elsif option == 'bytes' File.open(filename) do |f| f.each_byte{ n += 1 } end n elsif %w[characters chars].include?(option) File.open(filename) do |f| n += 1 while f.getc end n elsif option == 'words' File.foreach(filename) do |line| n += line.split.length end n else bytes, chars, lines, words = 0, 0, 0, 0 File.foreach(filename) do |line| lines += 1 words += line.split.length chars += line.chars.length end File.open(filename) do |f| bytes += 1 while f.getc end [bytes, chars, words, lines] end end
Returns an array of each program
within path
, or nil if it cannot be found.
On Windows, it looks for executables ending with the suffixes defined in your PATHEXT environment variable, or ‘.exe’, ‘.bat’ and ‘.com’ if that isn’t defined, which you may optionally include in program
.
Examples:
File.whereis('ruby') # => ['/usr/bin/ruby', '/usr/local/bin/ruby'] File.whereis('foo') # => nil
# File lib/ptools.rb, line 146 def self.whereis(program, path = ENV['PATH']) raise ArgumentError, 'path cannot be empty' if path.nil? || path.empty? paths = [] # Bail out early if an absolute path is provided. if program =~ /^\/|^[a-z]:[\\\/]/i program += WIN32EXTS if MSWINDOWS && File.extname(program).empty? program = program.tr(File::ALT_SEPARATOR, File::SEPARATOR) if MSWINDOWS found = Dir[program] if found[0] && File.executable?(found[0]) && !File.directory?(found[0]) if File::ALT_SEPARATOR return found.map{ |f| f.tr(File::SEPARATOR, File::ALT_SEPARATOR) } else return found end else return nil end end # Iterate over each path glob the dir + program. path.split(File::PATH_SEPARATOR).each do |dir| next unless File.exist?(dir) # In case of bogus second argument file = File.join(dir, program) # Dir[] doesn't handle backslashes properly, so convert them. Also, if # the program name doesn't have an extension, try them all. if MSWINDOWS file = file.tr(File::ALT_SEPARATOR, File::SEPARATOR) file += WIN32EXTS if File.extname(program).empty? end found = Dir[file].first # Convert all forward slashes to backslashes if supported if found && File.executable?(found) && !File.directory?(found) found.tr!(File::SEPARATOR, File::ALT_SEPARATOR) if File::ALT_SEPARATOR paths << found end end paths.empty? ? nil : paths.uniq end
Looks for the first occurrence of program
within path
.
On Windows, it looks for executables ending with the suffixes defined in your PATHEXT environment variable, or ‘.exe’, ‘.bat’ and ‘.com’ if that isn’t defined, which you may optionally include in program
.
Returns nil if not found.
Examples:
File.which('ruby') # => '/usr/local/bin/ruby' File.which('foo') # => nil
# File lib/ptools.rb, line 93 def self.which(program, path = ENV['PATH']) raise ArgumentError, 'path cannot be empty' if path.nil? || path.empty? # Bail out early if an absolute path is provided. if program =~ /^\/|^[a-z]:[\\\/]/i program += WIN32EXTS if MSWINDOWS && File.extname(program).empty? found = Dir[program].first if found && File.executable?(found) && !File.directory?(found) return found else return nil end end # Iterate over each path glob the dir + program. path.split(File::PATH_SEPARATOR).each do |dir| dir = File.expand_path(dir) next unless File.exist?(dir) # In case of bogus second argument file = File.join(dir, program) # Dir[] doesn't handle backslashes properly, so convert them. Also, if # the program name doesn't have an extension, try them all. if MSWINDOWS file = file.tr(File::ALT_SEPARATOR, File::SEPARATOR) file += WIN32EXTS if File.extname(program).empty? end found = Dir[file].first # Convert all forward slashes to backslashes if supported if found && File.executable?(found) && !File.directory?(found) found.tr!(File::SEPARATOR, File::ALT_SEPARATOR) if File::ALT_SEPARATOR return found end end nil end
Private Class Methods
Returns whether or not the given text
contains a BOM marker. If present, we can generally assume it’s a text file.
# File lib/ptools.rb, line 392 def self.check_bom?(file) text = File.read(file, 4).force_encoding('utf-8') bool = false bool = true if text[0, 3] == "\xEF\xBB\xBF" bool = true if text[0, 4] == "\x00\x00\xFE\xFF" || text[0, 4] == "\xFF\xFE\x00\x00" bool = true if text[0, 2] == "\xFF\xFE" || text[0, 2] == "\xFE\xFF" bool end