Passing ENV vars from bash to ruby

env_vars.rb

# env_vars.rb

puts "A:#{ENV["AAA"]}"
puts "B:#{ENV["BBB"]}"
puts "C:#{ENV["CCC"]}"
puts "D:#{ENV["DDD"]}"

env_vars.sh

# env_vars.sh

AAA=1
BBB=2
export BBB
export CCC=3

DDD="4" ruby env_vars.rb

output

$ ./env_vars.sh 
A:
B:2
C:3
D:4