Advanced

tail

• tail /var/log/maillog -f

fdisk

• df -h
• fdisk -l
• fdisk -l /dev/sda
• Create new partition
  • fdisk /dev/sdb
  • m
  • n
  • p
  • 1
  • ENTER
  • ENTER
  • w
  • partprobe
  • fdisk -l /dev/sdb

Recover root password

• Press E to edit boot menu
• Add rd.break at the line of "linux16"
• Press Ctrl+X
• mount -o remount,rw /sysroot
• chroot /sysroot
• passwd
• touch /.autorelabel

User Management

• UID starts from 1000
• /etc/passwd
• /etc/shadow
• /etc/group
• /etc/gshadow
• /etc/sudoers
• useradd tshen -c "Terry Shen"
• passwd tshen
• groupadd
• userdel
• groupdel
• usermod
• groupmod

Join in A Windows Domain

• yum install realmd sssd adcli samba-common-tools
• realm discover corp.alphabook.cn
• realm join corp.alphabook.cn
• vi /etc/sssd/sssd.conf
  • cache_credentials = True
  • use_fully_qualified_names = False
  • fallback_homedir = /home/%u
• systemctl is-enabled sssd
• systemctl enable sssd
• systemctl restart sssd

Mailx

• yum info mailx
• yum install mailx sendmail
• echo "My Body" | mailx -r "from@alphabook.cn" -s "My Subject" -S smtp=smtp.alphabook.cn -v "to@alphabook.cn"
• Error: My unqualified host name (linux01) unknown
  • vi /etc/hosts
  • 127.0.0.1 linux01 linux01.corp.alphabook.cn