test.sh

#!/bin/bash

STR=ABC-0

if [[ "$STR" =~ "-0$" ]]; then
  echo A
else
  echo B
fi

$ bash --version
GNU bash, version 3.2.25(1)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.
$ ./test.sh
A

↑バージョン差異↓ が原因だろうか。bash v4の方で、結果をAにするにはどうしたらいいだろうか？

$ bash --version
GNU bash, version 4.1.7(1)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
$ ./test.sh
B

http://d.hatena.ne.jp/adsaria/20100107/1262842850
にて解決。