Ignore signals without modifying your program.

ignoresig.rb

#!/usr/bin/env ruby
require 'getoptlong'

include Process
include Signal

$ignored_signals = ["CLD"]

def usage(strm)
  strm.puts <<-EOF
Usage: #{$0} [-h] [-s sig] [--signal=sig] [--help] [--] command [arguments...]
	EOF
end

opts = GetoptLong.new(
	['--signal', '-s', GetoptLong::REQUIRED_ARGUMENT],
	['--help', '-h', GetoptLong::NO_ARGUMENT]
)
opts.each do |opt, arg|
	case opt
	when '--signal'
		$ignored_signals << arg
	when '--help'
		usage $stdout
		exit true
	end
end

if ARGV.length < 1
	usage $stderr
	exit false
end

$ignored_signals.each do |signal|
	unless Signal.list.include?(signal)
		$stderr.puts "Signal \"#{signal}\" not found"
		exit false
	end
end

$child_pid = nil

Signal.list.each do |(signal, _)|
  next if $ignored_signals.include?(signal)
  trap signal do
    begin
      kill signal, $child_pid if $child_pid
    rescue Errno::ESRCH
    end
  end
end

$child_pid = fork do
  setpgrp
  exec ARGV[0], *ARGV[1, ARGV.length - 1]
end

waitpid $child_pid until $? && $?.exitstatus
exit $?.exitstatus