1、passwd 命令，手动修改：
[root@localhost testuser]# passwd testuser
Changing password for user testuser.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.
[root@localhost testuser]#
2、passwd 命令，命令行修改：
[root@localhost testuser]# echo '!@#$5678'|passwd --stdin testuser
3、chpasswd 命令，命令行修改
[root@localhost testuser]# echo 'testuser:!@#$5678'|chpasswd