https://superuser.com/questions/1247541/make-bash-completion-to-ignore-exe-extention-in-cygwin
https://superuser.com/questions/1072481/tab-completion-for-command-arguments-fail-in-cygwin-due-to-exe-suffix
https://github.com/scop/bash-completion/issues/164
--- a/.bash_completion Wed Aug 30 10:37:48 2017 +0300
+++ b/.bash_completion Tue Sep 05 17:35:44 2017 +0300
@@ -1,5 +1,7 @@
# -*- mode: shell-script -*-
+[[ "$OSTYPE" = cygwin ]] && shopt -s completion_strip_exe
+
# user commands see only users
complete -u su passwd write chfn groups slay w sux