CentOS 7 notes

# change hostname

hostnamectl set-hostname HOSTNAME

# bash update system

yum install -y epel-release
yum update -y

# bash auto command

yum install -y bash-completion bash-completion-extras
source /etc/profile.d/bash_completion.sh    

# bash install a minimal friendly set of programs

yum install -y setroubleshoot mc nano wget tcpdump net-tools git smartmontools mdadm    

# look list kernel core

rpm -q kernel

# clean old kernal core --count=2 their number

package-cleanup --oldkernels --count=2

# update repolist

sed -i s/mirror.centos.org/vault.centos.org/g /etc/yum.repos.d/*.repo
sed -i s/^#.*baseurl=http/baseurl=http/g /etc/yum.repos.d/*.repo
sed -i s/^mirrorlist=http/#mirrorlist=http/g /etc/yum.repos.d/*.repo