String

Colorize your outputs

Since we mostly work with the command-line, we need our output to be more elegant. Here are the main colors you may need to do so. You can always add to this set.

class String
  def red; colorize(self, "\e[1m\e[31m"); end
  def green; colorize(self, "\e[1m\e[32m"); end
  def dark_green; colorize(self, "\e[32m"); end
  def yellow; colorize(self, "\e[1m\e[33m"); end
  def blue; colorize(self, "\e[1m\e[34m"); end
  def dark_blue; colorize(self, "\e[34m"); end
  def purple; colorize(self, "\e[35m"); end
  def dark_purple; colorize(self, "\e[1;35m"); end
  def cyan; colorize(self, "\e[1;36m"); end
  def dark_cyan; colorize(self, "\e[36m"); end
  def pure; colorize(self, "\e[0m\e[28m"); end
  def bold; colorize(self, "\e[1m"); end
  def colorize(text, color_code) "#{color_code}#{text}\e[0m" end
end

All you need is to call the color when you puts it

puts "RubyFu".red
puts "RubyFu".green
puts "RubyFu".yellow.bold

To understand this code, let’s explain it with a diagram

\033  [0;  31m
 ^     ^    ^    
 |     |    |
 |     |    |--------------------------------------- [The color number]
 |     |-------------------- [The modifier]            (ends with "m")
 |-- [Escaped character]           | 0 - normal                     
     (you can use "\e")            | 1 - bold
                                   | 2 - normal again
                                   | 3 - background color
                                   | 4 - underline
                                   | 5 - blinking

Or you can use an external gem called [colorized] for fancier options

gem install colorize

Then just require it in your script

require 'colorize'

Overwriting Console Output

It’s awesome to have more flexibility in your terminal, and sometimes we need to do more with our scripts.

Overwriting console output makes our applications elegant and less noisy for repeated outputs like counting and loading progress bars.

I’ve read a how-to about bash Prompt cursor movement and I found it is convenient to have in our scripts. Here’s what I’ve found so far

- Position the Cursor:
  \033[<L>;<C>H
     Or
  \033[<L>;<C>f
  puts the cursor at line L and column C.
- Move the cursor up N lines:
  \033[<N>A
- Move the cursor down N lines:
  \033[<N>B
- Move the cursor forward N columns:
  \033[<N>C
- Move the cursor backward N columns:
  \033[<N>D
- Clear the screen, move to (0,0):
  \033[2J
- Erase to end of line:
  \033[K
- Save cursor position:
  \033[s
- Restore cursor position:
  \033[u

So to test these I created the following PoC

#!/usr/bin/env ruby
# KING SABRI | @KINGSABRI
(1..3).map do |num|
  print "\rNumber: #{num}"
  sleep 0.5
  print ("\033[1B")    # Move cursor down 1 line 
  ('a'..'c').map do |char|
    print "\rCharacter: #{char}"
    print  ("\e[K")
    sleep 0.5
    print ("\033[1B")    # Move cursor down 1 lines
    ('A'..'C').map do |char1|
      print "\rCapital letters: #{char1}"
      print  ("\e[K")
      sleep 0.3
    end
    print ("\033[1A")    # Move curse up 1 line
  end
  print ("\033[1A")    # Move curse up 1 line
end
print ("\033[2B")    # Move cursor down 2 lines
puts ""

So far so good, but why don’t we make these as Ruby methods for more elegant usage? So I came up with the following

# KING SABRI | @KINGSABRI
class String
  def mv_up(n=1)
    cursor(self, "\033[#{n}A")
  end
  def mv_down(n=1)
    cursor(self, "\033[#{n}B")
  end
  def mv_fw(n=1)
    cursor(self, "\033[#{n}C")
  end
  def mv_bw(n=1)
    cursor(self, "\033[#{n}D")
  end
  def cls_upline
    cursor(self, "\e[K")
  end
  def cls
    # cursor(self, "\033[2J")
    cursor(self, "\e[H\e[2J")
  end
  def save_position
    cursor(self, "\033[s")
  end
  def restore_position
    cursor(self, "\033[u")
  end
  def cursor(text, position)
    "\r#{position}#{text}"
  end
end

Then as a PoC, I’ve used the same previous PoC code (after updating String class on-the-fly in the same script)

#!/usr/bin/env ruby
# KING SABRI | @KINGSABRI
# Level 1
(1..3).map do |num|
  print "\rNumber: #{num}"
  sleep 0.7
  # Level 2
  ('a'..'c').map do |char|
      print "Characters: #{char}".mv_down
      sleep 0.5
      # Level 3
      ('A'..'C').map do |char1|
          print "Capital: #{char1}".mv_down
          sleep 0.2
          print "".mv_up
      end
      print "".mv_up
  end
  sleep 0.7
end
print "".mv_down 3

It’s much more elegant, isn’t it? Say yes plz

Some application…

Create Progress Percent

(1..10).each do |percent|
  print "#{percent*10}% complete\r"
  sleep(0.5)
  print  ("\e[K") # Delete current line
end
puts "Done!"

Another example

(1..5).to_a.reverse.each do |c|
  print "\rI'll exit after #{c} second(s)"
  print "\e[K"
  sleep 1
end

Using our elegant way (after updating String class on-the-fly)

(1..5).to_a.reverse.each do |c|
  print "I'll exit after #{c} second".cls_upline
  sleep 1
end
puts