ClearEnvCache clears saved environment values so that a new read access the environment again.

EnvOrDefaultBool returns the value set by the specified environment variable, if any, otherwise the specified default value.

EnvOrDefaultBytes returns the value set by the specified environment variable, if any, otherwise the specified default value.

EnvOrDefaultDuration returns the value set by the specified environment variable, if any, otherwise the specified default value.

EnvOrDefaultFloat64 returns the value set by the specified environment variable, if any, otherwise the specified default value.

EnvOrDefaultInt returns the value set by the specified environment variable, if any, otherwise the specified default value.

EnvOrDefaultInt64 returns the value set by the specified environment variable, if any, otherwise the specified default value.

EnvOrDefaultString returns the value set by the specified environment variable, if any, otherwise the specified default value.

EnvString returns the value set by the specified environment variable.

ExternalEnvString returns the value set by the specified environment variable.

GetEnvReport dumps all configuration variables that may have been used and their value.

GetEnvVarsUsed returns the names of all environment variables that may have been used.

GetShellCommand returns a complete command to run with a prefix of the command line.

HomeDir returns the user's home directory, as determined by the env var HOME, if it exists, and otherwise the system's idea of the user configuration (e.g.

TestSetEnv sets an environment variable and the cleanup function resets it to the original value.

TestUnsetEnv unsets an environment variable and the cleanup function resets it to the original value.

TB is a slimmed down version of testing.T for use below.