Environment Variables

Some apps store config information in environment variables.

• Every process has its own set of environment variables
• Environment variables die with their process
• A process gets its environment variables from its parent
  • if you use `backticks` to shell out and echo, it uses the ruby process's ENV hash

Environment Variables != Shell Variables

# set a local variable
$ MARCO='polo'
$ ruby -e "puts ENV['MARCO']"

# export converts local var to environment var
$ export MARCO
$ ruby -e "puts ENV['MARCO']"
polo

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