Class: Segua

Inherits:
Object
  • Object
show all
Defined in:
lib/segua.rb,
lib/segua/version.rb

Overview

Segua tracks changes in files in @dir, always following the most recently changed.

It emulates tail -f. tail's argument, -f, stands for "follow." "Segua" is the imperative form of "to follow" in Italian.

Constant Summary collapse

Version =

Gem version

"0.1.1"

Instance Method Summary collapse

Constructor Details

#initialize(dir) ⇒ Segua

Create a new Segua against dir.



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# File 'lib/segua.rb', line 9

def initialize(dir)
  @dir = dir
end

Instance Method Details

#follow ⇒ Object

Following the file with the most recent modification time, print each line of the file, indefinitely.



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# File 'lib/segua.rb', line 24

def follow
  file_name = latest_file
  while file_name.nil?
    sleep 1
    file_name = latest_file
  end

  print_file_update(file_name)
  handle = File.open file_name

  while true
    line = handle.gets
    if line.nil?
      sleep 0.5
    else
      puts line.chomp.strip
    end
    new_file_name = latest_file
    while new_file_name.nil?
      sleep 1
      new_file_name = latest_file
    end
    if new_file_name != file_name
      print_file_update(new_file_name)
      file_name = new_file_name
      handle.close
      handle = File.open file_name
      next
    end
  end
  handle.close
end

#latest_file ⇒ Object

Find, among all of the files located directly inside dir, the one with the most recent modification time. Returns the full file path as a String.



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# File 'lib/segua.rb', line 59

def latest_file
  Dir.entries(@dir).map {|f| File.join(@dir, f) }.reject {|f| File.directory?(f) }.inject do |memo,file|
  File.mtime(memo) > File.mtime(file) ? memo : file
  end
end

#print_file_update(file_name) ⇒ Object

Print a few lines before switching to a new file, indicating the new file.



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# File 'lib/segua.rb', line 14

def print_file_update(file_name)
  puts ""
  puts "SEGUA: ==================" + ('='*file_name.length)
  puts "SEGUA: most recent file: #{file_name}"
  puts "SEGUA: ==================" + ('='*file_name.length)
  puts ""
end