Linux 登录后出现消息‘-bash：/dev/null：权限被拒绝’

Question

我通过putty登录redhat server 7.4。

login as: john
[email protected]'s password:
Last login: Mon Sep 12 10:45:16 2022 from 172.24.7.200
-bash: /dev/null: Permission denied
-bash: /dev/null: Permission denied
-bash: /dev/null: Permission denied    
-bash: /dev/null: Permission denied

我如何知道“权限被拒绝”消息的原因？