設定使用者密碼

1. passwd 命令設定或變更密碼

   [root@kvm8 ~]# passwd --help
   Usage: passwd [options] [LOGIN]
   
   Options:
     -a, --all                     report password status on all accounts
     -d, --delete                  delete the password for the named account
     -e, --expire                  force expire the password for the named account
     -h, --help                    display this help message and exit
     -k, --keep-tokens             change password only if expired
     -i, --inactive INACTIVE       set password inactive after expiration
                                   to INACTIVE
     -l, --lock                    lock the password of the named account
     -n, --mindays MIN_DAYS        set minimum number of days before password
                                   change to MIN_DAYS
     -q, --quiet                   quiet mode
     -r, --repository REPOSITORY   change password in REPOSITORY repository
     -R, --root CHROOT_DIR         directory to chroot into
     -P, --prefix PREFIX_DIR       directory prefix
     -S, --status                  report password status on the named account
     -u, --unlock                  unlock the password of the named account
     -w, --warndays WARN_DAYS      set expiration warning days to WARN_DAYS
     -x, --maxdays MAX_DAYS        set maximum number of days before password
                                   change to MAX_DAYS
     -s, --stdin                   read new token from stdin
   
   參數：
   --stdin  ：經由標準輸入取得密碼，配合管線處理，可大量更改帳號密碼。
   

2. 使用 --stdin 選項設定 deyu1, deyu2, deyu3, deyu4 的密碼。

   [root@kvm8 ~]# echo 123qwe | passwd --stdin deyu1
   BAD PASSWORD: The password is shorter than 8 characters
   [root@kvm8 ~]# echo 123qwe | passwd --stdin deyu2
   BAD PASSWORD: The password is shorter than 8 characters
   [root@kvm8 ~]# echo 123qwe | passwd --stdin deyu3
   BAD PASSWORD: The password is shorter than 8 characters
   [root@kvm8 ~]# echo 123qwe | passwd --stdin deyu4
   BAD PASSWORD: The password is shorter than 8 characters
   

3. ssh deyu1 測試密碼，登入成功。

   [root@kvm8 ~]# ssh deyu1@kvm8
   The authenticity of host 'kvm8 (192.168.122.8)' can't be established.
   ED25519 key fingerprint is SHA256:UW9HYWrgRRWBjnpqAMPE+Nu4eM1K1FyU15owqZ5YVsw.
   This key is not known by any other names.
   Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
   Warning: Permanently added 'kvm8' (ED25519) to the list of known hosts.
   deyu1@kvm8's password:
   

4. 登出 deyu1。

   [deyu1@kvm8 ~]$
   logout
   Connection to kvm8 closed.