is-*: fix for bash v3, for macos cron

`env -i DOROTHY="$DOROTHY" "$(which is-linux)"` returned 0 on macos, as it was using `/bin/bash` which is bash v3

this can also be proven by:

```
#!/bin/bash

function is_linux_test() (
	source "$DOROTHY/sources/bash.bash"
	echo-segment --h1="TEST: $0"

	local os
	os="$(uname -s)"
	if test "$os" = 'Linux'; then
		eval-tester --name='is linux' --status='0' \
			-- is-linux --question='is linux'
	else
		eval-tester --name='is not linux' --status='1' \
			-- is-linux --question='is not linux'
	fi

	echo-segment --g1="TEST: $0"
	return 0
)
function is_linux() (
	source "$DOROTHY/sources/bash.bash"

	test "$(uname -s)" = 'Linux'
)

# fire if invoked standalone
if test "$0" = "${BASH_SOURCE[0]}"; then
	if test "$*" = '--test'; then
		is_linux_test
	else
		is_linux "$@"
	fi
fi
```

Note that `/usr/bin/env bash` is replaced with `/bin/bash`, this is because `/usr/bin/env bash` seems to ignore `env -i`.

Other changes include:

- dorothy: move env setup to be prior to bash.bash loading, such that bash.bash can be loaded under cron environment
- `TERM_PROGRAM` may not always be defined
- `is-color-enabled` now checks fron cron environment to disable color

commands/dorothy

@@ -29,8 +29,52 @@ function dorothy() (
 		exit 6 # ENXIO 6 Device not configured
 	fi
 
+	# vars that should be exported to subshells, which may or may not be inherited, as setup-environment-commands has not run yet
+	local self
+	export DOROTHY ZDOTDIR PATH XDG_CONFIG_HOME XDG_CACHE_HOME XDG_BIN_HOME XDG_DATA_HOME XDG_STATE_HOME
+	if test -z "${DOROTHY-}"; then
+		# handle cron situation (dorothy is installed, however environment is empty)
+		# `env -i "$(which dorothy)" run env` <-- whoami returns user who has dorothy installed:
+		# `sudo env -i "$(which dorothy)" run env` <-- whoami returns root, who does not have dorothy installed
+		# @todo consider if this runs on zsh and bash v3
+		self="${BASH_SOURCE:-"$0"}"
+		if [[ $self == *'.local/share/dorothy/commands/dorothy' ]] && test -f "$self"; then
+			DOROTHY="${self%/commands/dorothy*}"
+			if test -z "${HOME-}"; then
+				export HOME
+				HOME="${self%/.local/share/dorothy/commands/dorothy*}"
+			fi
+			if test -z "${USER-}"; then
+				export USER
+				USER="$(basename "$HOME")"
+			fi
+		else
+			# handle fresh install situation
+			DOROTHY=''
+		fi
+	fi
+	if test -z "${ZDOTDIR-}"; then
+		ZDOTDIR=''
+	fi
+	if test -z "${XDG_CONFIG_HOME-}"; then
+		XDG_CONFIG_HOME="$HOME/.config"
+	fi
+	if test -z "${XDG_CACHE_HOME-}"; then
+		XDG_CACHE_HOME="$HOME/.cache"
+	fi
+	if test -z "${XDG_BIN_HOME-}"; then
+		XDG_BIN_HOME="$HOME/.local/bin"
+	fi
+	if test -z "${XDG_DATA_HOME-}"; then
+		XDG_DATA_HOME="$HOME/.local/share"
+	fi
+	if test -z "${XDG_STATE_HOME-}"; then
+		XDG_STATE_HOME="$HOME/.local/state"
+	fi
+	mkdir -p "$XDG_CONFIG_HOME" "$XDG_CACHE_HOME" "$XDG_BIN_HOME" "$XDG_DATA_HOME" "$XDG_STATE_HOME"
+
 	# source [bash.bash] for sensible defaults if it exists
-	if test -n "${DOROTHY-}" -a -f "${DOROTHY-}/sources/bash.bash"; then
+	if test -n "$DOROTHY" -a -f "$DOROTHY/sources/bash.bash"; then
 		source "$DOROTHY/sources/bash.bash"
 	else
 		# otherwise apply them manually
@@ -177,58 +221,6 @@ function dorothy() (
 		done
 	}
 
-	# =====================================
-	# Environment
-
-	# vars that should be exported to subshells, which may or may not be inherited, as setup-environment-commands has not run yet
-	local self
-	export DOROTHY ZDOTDIR PATH XDG_CONFIG_HOME XDG_CACHE_HOME XDG_BIN_HOME XDG_DATA_HOME XDG_STATE_HOME
-	if test -z "${DOROTHY-}"; then
-		# handle cron situation (dorothy is installed, however environment is empty)
-		# `env -i "$(which dorothy)" run env` <-- whoami returns user who has dorothy installed:
-		# `sudo env -i "$(which dorothy)" run env` <-- whoami returns root, who does not have dorothy installed
-		# @todo consider if this runs on zsh and bash v3
-		self="${BASH_SOURCE:-"$0"}"
-		if [[ $self == *'.local/share/dorothy/commands/dorothy' ]] && test -f "$self"; then
-			DOROTHY="${self%/commands/dorothy*}"
-			if test -z "${HOME-}"; then
-				export HOME
-				HOME="${self%/.local/share/dorothy/commands/dorothy*}"
-			fi
-			if test -z "${USER-}"; then
-				export USER
-				USER="$(basename "$HOME")"
-			fi
-			if test -n "${CRON-}" -o -n "${CRONITOR_EXEC-}"; then
-				# disable colour, different lines of bash v3 compat
-				export COLOR
-				COLOR=false
-			fi
-		else
-			# handle fresh install situation
-			DOROTHY=''
-		fi
-	fi
-	if test -z "${ZDOTDIR-}"; then
-		ZDOTDIR=''
-	fi
-	if test -z "${XDG_CONFIG_HOME-}"; then
-		XDG_CONFIG_HOME="$HOME/.config"
-	fi
-	if test -z "${XDG_CACHE_HOME-}"; then
-		XDG_CACHE_HOME="$HOME/.cache"
-	fi
-	if test -z "${XDG_BIN_HOME-}"; then
-		XDG_BIN_HOME="$HOME/.local/bin"
-	fi
-	if test -z "${XDG_DATA_HOME-}"; then
-		XDG_DATA_HOME="$HOME/.local/share"
-	fi
-	if test -z "${XDG_STATE_HOME-}"; then
-		XDG_STATE_HOME="$HOME/.local/state"
-	fi
-	mkdir -p "$XDG_CONFIG_HOME" "$XDG_CACHE_HOME" "$XDG_BIN_HOME" "$XDG_DATA_HOME" "$XDG_STATE_HOME"
-
 	# =====================================
 	# Variables
 

commands/is-admin

@@ -3,7 +3,11 @@
 function is_admin() (
 	source "$DOROTHY/sources/bash.bash"
 
-	is-user-in-group --group=admin
+	if is-user-in-group --group=admin; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-alpine

@@ -3,8 +3,8 @@
 function is_alpine() (
 	source "$DOROTHY/sources/bash.bash"
 
-	if test -f /etc/os-release; then
-		grep -qi 'ID=alpine' /etc/os-release 2>/dev/null
+	if test -f /etc/os-release && grep -qi 'ID=alpine' /etc/os-release 2>/dev/null; then
+		return 0
 	else
 		return 1
 	fi

commands/is-apk

@@ -3,7 +3,11 @@
 function is_apk() (
 	source "$DOROTHY/sources/bash.bash"
 
-	command-exists apk
+	if command-exists apk; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-appimage

@@ -3,7 +3,11 @@
 function is_appimage() (
 	source "$DOROTHY/sources/bash.bash"
 
-	command-exists 'appimaged' 'appimagetool' 'mkappimage'
+	if command-exists 'appimaged' 'appimagetool' 'mkappimage'; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-apple-silicon

@@ -3,7 +3,11 @@
 function is_apple_silicon() (
 	source "$DOROTHY/sources/bash.bash"
 
-	is-mac && test "$(uname -p)" = 'arm' -o "$(uname -m)" = 'arm64'
+	if is-mac && test "$(uname -p)" = 'arm' -o "$(uname -m)" = 'arm64'; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-apt

@@ -5,7 +5,11 @@
 function is_apt() (
 	source "$DOROTHY/sources/bash.bash"
 
-	command-exists apt-get
+	if command-exists apt-get; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-arch

@@ -3,7 +3,11 @@
 function is_arch() (
 	source "$DOROTHY/sources/bash.bash"
 
-	test -f /etc/arch-release
+	if test -f /etc/arch-release; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-array-count

@@ -5,7 +5,11 @@
 function is_array_count() (
 	source "$DOROTHY/sources/bash.bash"
 
-	test "$(get-array-count "${@:2}")" -eq "$1"
+	if test "$(get-array-count "${@:2}")" -eq "$1"; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-array-count-ge

@@ -5,7 +5,11 @@
 function is_array_count_ge() (
 	source "$DOROTHY/sources/bash.bash"
 
-	test "$(get-array-count "${@:2}")" -ge "$1"
+	if test "$(get-array-count "${@:2}")" -ge "$1"; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-brew

@@ -4,12 +4,11 @@ function is_brew() (
 	source "$DOROTHY/sources/bash.bash"
 
 	# workaround for our [brew] helper
-	if is-mac; then
-		if test -x "${HOMEBREW_PREFIX-}/bin/brew"; then
-			return 0
-		fi
+	if is-mac && test -x "${HOMEBREW_PREFIX-}/bin/brew"; then
+		return 0
+	else
+		return 1
 	fi
-	return 1
 )
 
 # fire if invoked standalone

commands/is-btrfs

@@ -55,6 +55,7 @@ function is_btrfs() (
 			return 1
 		fi
 	done
+	return 0
 )
 
 # fire if invoked standalone

commands/is-ci

@@ -35,7 +35,11 @@ function is_ci() (
 	# =====================================
 	# Action
 
-	is-affirmative --ignore-empty -- "${CI-}" "${CONTINUOUS_INTEGRATION-}" "${BUILD_NUMBER-}" "${RUN_ID-}" || return 1
+	if is-affirmative --ignore-empty -- "${CI-}" "${CONTINUOUS_INTEGRATION-}" "${BUILD_NUMBER-}" "${RUN_ID-}"; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-color-enabled

@@ -12,7 +12,7 @@ function is_color_enabled() (
 			use_color="\$(is-color-enabled <default> -- "\$@")"
 
 			QUIRKS:
-			Checks for [--[no-]color[s]=[yes|no]] values, as well as [[NO[_]]COLOR] environment variables.
+			Checks for [--[no-]color[s]=[yes|no]] values, as well as [[NO[_]]COLOR] and [CRON], [CRONITOR_EXEC], and [TERM] environment variables.
 		EOF
 		if test "$#" -ne 0; then
 			echo-error "$@"
@@ -52,6 +52,10 @@ function is_color_enabled() (
 				echo-non-affirmative -- "$NO_COLOR"
 			elif test -n "${NOCOLOR-}"; then
 				echo-non-affirmative -- "$NOCOLOR"
+			elif test -n "${CRON-}" -o -n "${CRONITOR_EXEC-}" -o -z "${TERM-}" -o "${TERM-}" = 'dumb'; then
+				# cron strips most env vars, except that defined in [crontab -e], bash however does itself set TERM=dumb
+				# https://unix.stackexchange.com/a/411097
+				print_line 'no'
 			else
 				print_line "$default"
 			fi

commands/is-desktop-session

@@ -10,7 +10,11 @@
 function is_desktop_session() (
 	source "$DOROTHY/sources/bash.bash"
 
-	is-mac || test -n "${XDG_CURRENT_DESKTOP-}" -o -n "${DESKTOP_SESSION-}"
+	if is-mac || test -n "${XDG_CURRENT_DESKTOP-}" -o -n "${DESKTOP_SESSION-}"; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-digit

@@ -3,7 +3,11 @@
 function is_digit() (
 	source "$DOROTHY/sources/bash.bash"
 
-	is-number "$1" && test "$1" -ge 0 -a "$1" -le 9
+	if is-number "$1" && test "$1" -ge 0 -a "$1" -le 9; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-dnf

@@ -35,7 +35,11 @@ function is_dnf() (
 	# =====================================
 	# Action
 
-	command-exists dnf
+	if command-exists dnf; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-empty-ls

@@ -3,7 +3,11 @@
 function is_empty_ls() (
 	source "$DOROTHY/sources/bash.bash"
 
-	test "$(ls -A "$1")" = ''
+	if test -z "$(ls -A "$1")"; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-empty-size

@@ -7,7 +7,11 @@
 function is_empty_size() (
 	source "$DOROTHY/sources/bash.bash"
 
-	test "$(du -s "$1")" = $'0\t'"$1"
+	if test "$(du -s "$1")" = $'0\t'"$1"; then
+		return 0
+	else
+		return 1
+	fi
 )
 
 # fire if invoked standalone

commands/is-empty-string

@@ -48,9 +48,11 @@ function is_empty_string() (
 		help 'No <input> provided.'
 	elif test "$*" = '--help'; then
 		help
+	elif [[ $* =~ ^[[:space:]]*$ ]]; then
+		# value is only whitespace characters
+		return 0
 	else
-		# check if the value only whitespace characters
-		[[ $* =~ ^[[:space:]]*$ ]]
+		return 1
 	fi
 )
 

commands/is-empty-value

@@ -6,10 +6,14 @@ function is_empty_value() (
 	local value="${1-}"
 
 	# check for empty values, or check for an empty string
-	test -z "$value" -o \
+	if test -z "$value" -o \
 		"$value" = 'null' -o "$value" = 'NULL' -o \
 		"$value" = 'void' -o "$value" = 'VOID' -o \
-		"$value" = 'undefined' -o "$value" = 'UNDEFINED' || is-empty-string "$value"
+		"$value" = 'undefined' -o "$value" = 'UNDEFINED' || is-empty-string "$value"; then
+		return 0
+	else
+		return 1
+	fi
 
 	# don't consider 0 empty as version-compare believes 0 is a valid value
 )

commands/is-generic

@@ -38,9 +38,11 @@ function is_generic() (
 		help
 	elif test -z "$*"; then
 		return 0 # is generic
-	else
+	elif [[ $* =~ ubuntu|root|admin|super|user|localhost ]]; then
 		# don't include [local], as macos hostnames end in [.local]
-		[[ $* =~ ubuntu|root|admin|super|user|localhost ]]
+		return 0
+	else
+		return 1
 	fi
 )