busybox

busybox provides multiple GNU utilities in a single binary ececutable. The utilities in BusyBox have fewer options than their full-featured GNU cousins
Its modular so you can include or exclude commands or features at compile time

Install busybox on your linux os package manager, like apt in debian
#apt install busybox

run busybox applet for example
#busybox ls

run applet help
#busybox ls -h

or list
#busybox --list

or busybox applets
#busybox

or run busybox from any path
#./busybox

the linux initramfs can be built by busybox and applets

There are not many busybox versions for windows. The following site offers one

https://frippery.org/busybox

but has not many gnu utilities

copy the binary to any path and for example run
#busybox64.exe ls

There are 32-bit and other versions on page

The android version can be downloaded on termux install for example by apt
#apt install busybox

there is a busybox app on f-droid https://f-droid.org/en/packages/ru.meefik.busybox

The app requires root, for no root you will have to install it manually by extracting the busybox binary from app in your favorite apk extractor

the following extracter apps can be used https://f-droid.org/en/packages/axp.tool.apkextractor

https://apkpure.com/apk-extractor-and-recovery-apk-restore/com.androdev.apkextractor

https://apkpure.com/apk-extractor/braveheart.apps.apkextract

https://play.google.com/store/apps/details?id=braveheart.apps.apkextract

Extract the busybox app, go to lib > your binary version > libbusybox.so

replace binary version for example arm64-v8a for new androids mostly. Rename libbusybox.so to busybox and copy it to any path, not ext-card partition as it is non-executable. Mostly the home folder of your terminal app.

or download extracted arm64-v8a busybox binary here