ruby.md

tags
languages

CLI handlig

#!/usr/bin/env ruby
ARGV.each do|a|
  puts "Argument: #{a}"
end

STDERR.puts
input = gets.chomp

abort "optional msg" unless input == 'yes'

heredoc

https://ruby-doc.org/core-2.5.0/doc/syntax/literals_rdoc.html do not use <<HEREDOC

a = 1
query = <<-HTML.chomp # without trailing newline
  #{a}
  Article about heredocs

HTML

# with indentation:
  query = <<-HTML.chomp # without trailing newline
  #{a}
  Article about heredocs

HTML

  query = <<~HTML.chomp
    indented
  HTML
  # "indented"

interpolation disabled:

doc = <<-'TIME'
Current time is #{Time.now}
TIME

Profiling

start:

require 'profile'

# not sure about this (this is for cases when needed to profile some long running code but no time to wait when it finishes)
Signal.trap("INT") do
  puts 'bye'
  File.open('_profile.txt', 'w') do |f|
    Profiler__.print_profile(f)
  end
  exit
end

or

ruby -rprofile script.rb
ruby -rprofile -S some_executable

Gems

how to run an executable from a specific version of a gem:

rails _1.2.3_ -v

uninstall all gems

gem uninstall -aIx

compare gems versions:

if Bundler.environment.specs['rails'][0].version < Gem::Version.new('5')

Find gem path

Gem::Dependency.new('rails').to_spec.full_gem_path
#=> "/home/kuca/.rbenv/versions/1.9.3-p194/gemsets/candi/gems/rails-3.1.8"

Misc

parse cookies:

cookies = CGI::Cookie::parse(raw_cookie)
  .inject({}) { |data, (k,v)| data.merge(k => v.value.first) }