random: functions module for shellfire

This module provides an immature framework for accessing random values from shell script. It employs a number of fallback strategies, each of which sources a less random, less acceptable source. There are no known users, and you should consider this code alpha quality, subject to change, etc.

Compatibility

• Tag release_2015.0117.1750-1 is compatible with shellfire release release_2015.0117.1750-1.

Overview

For example, to generate a random number between 0 and 255:-

randomValue="$(random_generateBetween0To255)"

Importing

To import this module, add a git submodule to your repository. From the root of your git repository in the terminal, type:-

mkdir -p lib/shellfire
cd lib/shellfire
git submodule add "https://github.com/shellfire-dev/random.git"
cd -
git submodule init --update

You may need to change the url https://github.com/shellfire-dev/random.git" above if using a fork.

You will also need to add paths - include the module paths.d.

Namespace random

To use in code

If calling from another shellfire module, add to your shell code the line

core_usesIn random

in the global scope (ie outside of any functions). A good convention is to put it above any function that depends on functions in this module. If using it directly in a program, put this line inside the _program() function:-

_program()
{
	core_usesIn random
	…
}

Functions

---

random_generateBetween0To255()

Takes no parameters.

Writes a number between 0 and 255 inclusive to standard out, using the best available source of randomness.

---

random_generateBetween0AndModulus()

Parameter	Value	Optional
modulus	Modulus, must be between 1 and 255 (not validated)	No

Writes a number between 0 and modulus to standard out, using randomness from random_generateBetween0To255().

---

random_characterForEncodingLowerCaseOnly()

Takes no parameters.

Writes a lower case ASCII character or digit to standard out, using randomness from random_generateBetween0To255().

---

random_characterForEncodingLettersAndNumbers()

Takes no parameters.

Writes a lower or upper case ASCII character or digit to standard out, using randomness from random_generateBetween0To255().

---

random_characterForEncodingBase64Like()

Takes no parameters.

Writes an ASCII character suitable for use in Base64 encoding to standard out, using randomness from random_generateBetween0To255(). Highly experimental. Do not rely on this function being present.