# yum search --showduplicates salt
...
salt-2015.5.10-2.el6.noarch : A parallel remote execution system
salt-2015.5.10-2.el6.noarch : A parallel remote execution system
salt-2016.11.3-1.el6.noarch : A parallel remote execution system
...
# yum downgrade salt
降级指定版本后面写查询到的软件包全名。
...
salt-2015.5.10-2.el6.noarch : A parallel remote execution system
salt-2015.5.10-2.el6.noarch : A parallel remote execution system
salt-2016.11.3-1.el6.noarch : A parallel remote execution system
...
# yum downgrade salt
降级指定版本后面写查询到的软件包全名。
