补充一下,red hat下的bash版本是
GNU bash, version 3.1.17(1)-release (i686-redhat-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.
centos5.3下的bash版本是
GNU bash, version 3.2.25(1)-release (i686-redhat-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.