newt_colors.sh

#!/usr/bin/env sh


## Set newt color palette for dialogs
NEWT_COLORS_0='
    root=,blue
'
NEWT_COLORS_1='
    root=,blue
    checkbox=,blue
    entry=,blue
    label=blue,
    actlistbox=,blue
    helpline=,blue
    roottext=,blue
    emptyscale=blue
    disabledentry=blue,
'
NEWT_COLORS_2='
    root=green,black
    border=green,black
    title=green,black
    roottext=white,black
    window=green,black
    textbox=white,black
    button=black,green
    compactbutton=white,black
    listbox=white,black
    actlistbox=black,white
    actsellistbox=black,green
    checkbox=green,black
    actcheckbox=black,green
'
NEWT_COLORS_3='
    root=white,black
    border=black,lightgray
    window=lightgray,lightgray
    shadow=black,gray
    title=black,lightgray
    button=black,cyan
    actbutton=white,cyan
    compactbutton=black,lightgray
    checkbox=black,lightgray
    actcheckbox=lightgray,cyan
    entry=black,lightgray
    disentry=gray,lightgray
    label=black,lightgray
    listbox=black,lightgray
    actlistbox=black,cyan
    sellistbox=lightgray,black
    actsellistbox=lightgray,black
    textbox=black,lightgray
    acttextbox=black,cyan
    emptyscale=,gray
    fullscale=,cyan
    helpline=white,black
    roottext=lightgrey,black
'
export NEWT_COLORS=$NEWT_COLORS_0

I love it, I used it to improve my dialog boxes on my own Makefiles, I hope it helps to someone else as it helps me what you shared

# Makefile
NEWT_COLOR_PALETTE_DIALOGS="$(shell cat configs/whiptail-theme-green.cfg)"
WHIPTAIL_COLORED=export NEWT_COLORS=$(NEWT_COLOR_PALETTE_DIALOGS); whiptail

test:
	$(WHIPTAIL_COLORED) \
	--title "Alert" \
	--msgbox "something to describe here" 10 50 \
	2>&1 1>/dev/tty

# configs/whiptail-theme-green.cfg
root=green,black
border=green,black
title=green,black
roottext=white,black
window=green,black
textbox=white,black
button=black,green
compactbutton=white,black
listbox=white,black
actlistbox=black,white
actsellistbox=black,green
checkbox=green,black
actcheckbox=black,green

You can also use prettyfying config:

$ NEWT_MONO=1 whiptail ...

Or import themes by using NEWT_COLORS_FILE:

$ NEWT_COLORS_FILE=path/to/theme_file.txt whiptail ...

NEWT_COLORS_FILE=<(cat <<EOF
root=white,gray
window=white,lightgray
border=black,lightgray
shadow=white,black
button=black,green
actbutton=black,red
compactbutton=black,
title=black,
roottext=black,magenta
textbox=black,lightgray
acttextbox=gray,white
entry=lightgray,gray
disentry=gray,lightgray
checkbox=black,lightgray
actcheckbox=black,green
emptyscale=,black
fullscale=,red
listbox=black,lightgray
actlistbox=lightgray,gray
actsellistbox=black,green
EOF
) whiptail \
  --backtitle Backtitle \
  --title Title \
  --menu "$0" 0 0 2 1 One 2 Two 3 Three 4 Four

# zshrc
export NEWT_MONO=1

See: https://github.com/op/whiplash