Ready to go. Termux works directly with no rooting or setup required. At first start a minimal base system is installed automatically - you decide what to do next.
Termux vs Cygwin opinions
Not even the same platform!
Because it's completely different
Great mobility and UNIX like environment.
A terminal emulator and Unix environment bringing powerful terminal access to your Android-powered devices. **Android is already an os based on linux kernel. Moreover Termux is for Android/Linux whereas, CygWin is for Windows. ** Inabilities due to supporting the same platform, Termux is not even an alternative to Cygwin.
BusyBox is a single binary that provides several stripped-down Unix tools in a single executable. It runs in a variety of POSIX environments such as Linux, Android, FreeBSD and others. It was specifically created for embedded operating systems with very limited resources.