module ENV

Overview

ENV is a hash-like accessor for environment variables.

Example

# Set env var PORT to a default if not already set
ENV["PORT"] ||= "5000"
# Later use that env var.
puts ENV["PORT"].to_i

NOTE All keys and values are strings. You must take care to cast other types at runtime, e.g. integer port numbers.

Extended Modules

• Enumerable({String, String})

Defined in:

Class Method Summary

• .[](key : String) : String

  Retrieves the value for environment variable named key as a String.

• .[]=(key : String, value : String | Nil)

  Sets the value for environment variable named key as value.

• .[]?(key : String) : String | Nil

  Retrieves the value for environment variable named key as a String?.

• .clear : Nil
• .delete(key : String) : String | Nil

  Removes the environment variable named key.

• .each(& : Tuple(String, String) -> )

  Iterates over all KEY=VALUE pairs of environment variables, yielding both the key and value.

• .fetch(key, default : T) : String | T forall T

  Retrieves a value corresponding to the given key.

• .fetch(key) : String

  Retrieves a value corresponding to the given key.

• .fetch(key : String, &block : String -> T) : String | T forall T

  Retrieves a value corresponding to a given key.

• .has_key?(key : String) : Bool

  Returns true if the environment variable named key exists and false if it doesn't.

• .inspect(io)

  Writes the contents of the environment to io.

• .keys : Array(String)

  Returns an array of all the environment variable names.

• .pretty_print(pp)
• .values : Array(String)

  Returns an array of all the environment variable values.

Class Method Detail

ENV.each do |key, value|
  puts "#{key} => #{value}"
end

ENV.has_key?("NOT_A_REAL_KEY") # => false
ENV.has_key?("PATH")           # => true