[root@localhost ~]# mkdir /mnt/cdrom

[root@localhost ~]# mount /dev/cdrom /mnt/cdrom/

[root@localhost ~]# ll /mnt/cdrom/

1、进入repos目录，创建repo文件，增加cdrom源

[root@localhost ~]# cd /etc/yum.repos.d/

[root@localhost yum.repos.d]# ls

redhat.repo

[root@localhost yum.repos.d]# mv redhat.repo redhat.repo.bak

[root@localhost yum.repos.d]# vi iso.repo

[root@localhost yum.repos.d]# cat iso.repo

[base]
name=centos
baseurl=file:///mnt/cdrom
enable=1
gpgcheck=0
gpgkey=file:///mnt/cdrom/RPM-GPG-KEY-redhat-release

2、清理yum

yum clean all

3、安装tree命令

yum -y install tree