Module: Rails::Sh::Helpers

Included in:
Forkable
Defined in:
lib/rails/sh/helpers.rb

Instance Method Summary collapse

Instance Method Details

#lesspipe(*args) ⇒ Object

copy from pry: github.com/pry/pry

Create scrollable output via less!

This command runs ‘less` in a subprocess, and gives you the IO to its STDIN pipe so that you can communicate with it.

Example:

lesspipe do |less|
  50.times { less.puts "Hi mom!" }
end

The default less parameters are:

  • Allow colour

  • Don’t wrap lines longer than the screen

  • Quit immediately (without paging) if there’s less than one screen of text.

You can change these options by passing a hash to ‘lesspipe`, like so:

lesspipe(:wrap=>false) { |less| less.puts essay.to_s }

It accepts the following boolean options:

:color  => Allow ANSI colour codes?
:wrap   => Wrap long lines?
:always => Always page, even if there's less than one page of text?



31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
 
# File 'lib/rails/sh/helpers.rb', line 31

def lesspipe(*args)
  if args.any? and args.last.is_a?(Hash)
    options = args.pop
  else
    options = {}
  end

  output = args.first if args.any?

  params = []
  params << "-R" unless options[:color] == false
  params << "-S" unless options[:wrap] == true
  params << "-F" unless options[:always] == true
  if options[:tail] == true
    params << "+\\>"
    $stderr.puts "Seeking to end of stream..."
  end
  params << "-X"

  IO.popen("less #{params * ' '}", "w") do |less|
    if output
      less.puts output
    else
      yield less
    end
  end
end