Cygwin's default person interface is the bash shell running within the mintty terminal emulator.[25] The DLL also implements pseudo terminal (pty) devices, and Cygwin ships with numerous terminal emulators which are according to them, which includes rxvt/urxvt and xterm. The Edition of GCC that comes with Cygwin has numerous extensions https://acgwin42962.glifeblog.com/35902392/the-smart-trick-of-acgwin-that-no-one-is-discussing