I take my laptop to a friend's home yesterday,his internet connection is wired connection which the MAC and IP are binded,so I couldn't connect to internet with my laptop at his home unless I modify my laptop's MAC address .I'd never modified the MAC on Ubuntu before,then after I googled and googled,finally I found the ways to modify the MAC on Ubuntu. There are 2 ways to modify the MAC address on Ubuntu :~
Sometimes we need to know how many modules are available in Apache2,for example,you want to enable mod_rewrite in Linux server,normally we need to test if the mod_rewrite module has been added first.We can use command:apache2ctl -M to test how many modules are available in Apache2.
By default,If you hover a file/folder and right click mouse,you will only see a option Trash on pop-up menu for removing function.How to add a option Delete on it so that we can delete file/folder bypasses Trash? It is very easy,just go to Nautilus->Edit ->Preferences->Behavior and tick the option"Include a Delete command that bypasses Tras" which is on the most bottom,and then you may see option Delete already added to the pop-up menu.