1. Thay đổi default boot OS thành Windows
#cat /boot/grub2/grub.cfg |grep Windows
#grub2-set-default "Windows 7 (loader) (on /dev/sda1)"
#grub2-editenv list
#grub2-mkconfig -o /boot/grub2/grub.cfg

2. Xóa kernel cũ 
#uname -r    //xem kernel hien tai dang dung
#rpm -q kernel  //xem tat ca kernel
#yum -y remove kernel-2.6.3.23.14-115.fc8  //remove kernel 

3. Cập nhật cại kernel cho VirtualBox mỗi lần update Fedora
#yum install kmod-VirtualBox-OSE
#yum install kmod-VirtualBox

4. Remove user & root password
#passwd -d ninhld
#passwd -d root

5. Kiểm tra system log file
#tail -10000 /var/log/messages | grep telnet  (kiem tra log file su kien "telnet")

6. Disable all firewall
#systemctl stop firewalld.service

7. Add printer
- yum install system-config-printer
- open Print Settings
- Add / Network Print
- Driver DeskJet 400 (HP LaserJet 400) (vd cho máy in HP)

8. Add environment variable
- gedit ~/.bashrc
- Add: export PATH=$PATH:/path/to/bin

9. Diff command create patch file
+ Create patch
#diff -crB <old folder>  <new folder>  > new.patch
+ Update for old folder
#cp -rf new.patch <old folder>
#cd <old folder>
#patch -p1 -i new.patch