Hadoop3.1 startup error report

< H1 > hadoop startup error < / H1 >

configuration files are all written
and then started

[root@master logs]-sharp start-dfs.sh
Starting namenodes on [master]
Last login: Wed Jul  4 16:30:19 CST 2018 on pts/0
bash v3.2+ is required. Sorry.
Starting datanodes
Last login: Wed Jul  4 16:31:04 CST 2018 on pts/0
bash v3.2+ is required. Sorry.
Starting secondary namenodes [master]
Last login: Wed Jul  4 16:31:04 CST 2018 on pts/0
bash v3.2+ is required. Sorry.

shows that a bash version above v3.2 is required

but I read my version of bash that meets the requirements

GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2011 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.

solve