Passing ENV vars from bash to ruby
# env_vars.rb
puts "A:#{ENV["AAA"]}"
puts "B:#{ENV["BBB"]}"
puts "C:#{ENV["CCC"]}"
puts "D:#{ENV["DDD"]}"
# env_vars.sh
AAA=1
BBB=2
export BBB
export CCC=3
DDD="4" ruby env_vars.rb
$ ./env_vars.sh
A:
B:2
C:3
D:4