helper functions for quoting and escaping strings

 This package contains various helper functions
 for quoting and escaping an array of strings as expected by the "exec"
 calls on a Unix system into single strings that should be able to pass
 through shells and other intermediaries to produce the same result.
 .
 There is no single common quoting format that works for all shells
 and other layers, so this module makes no attempt to abstract away
 these differences. Instead, it provides a family of functions with the
 same signature so that the caller may select -- possibly dynamically --
 a suitable quoting function to use.