How to change MAC address in fedora

1. First step is to find the current MAC address and take a backup copy in a safe place.

To know your current MAC type:
$ ifconfig | grep HWaddr
eth0 Link encap:Ethernet HWaddr 00:19:48:2E:D1:27

The above hexadecimal numbers 00:19:48:2E:D1:27 is your MAC address for device eth0.
Simply copy and paste it in a file.

2. Now, time to change the MAC address this requires you to work as root user.
Take the network interface down
# ifdown eth0

Now, lets change the current MAC address to 00:E0:81:5C:B4:0F
# ifconfig eth0 hw ether 00:E0:81:5C:B4:0F

Take the network interface up again
# ifconfig eth0 up

Check if your MAC address is changed:
# ifconfig eth0 | grep HWaddr

Note:
Changing MAC address is only temporary. Once you reboot your machine, the operating system will reflect the physical MAC address burnt in your network card and not the MAC address you set.

Default Permission

Default Permission:
For Normal Users:-
1. On File:
-rw-rw-r-- or 664
2. On Directory:
drwxrwxr-x or 775

For users with root permissions:-
1. On File:
-rw-r--r-- or 644
2. On Directory:
drwxr-xr-x or 655

File and Directory Permissions

File Permissions:
1. -r--
content of the file can be read using command such as cat, less or more.
2. -rw-
Note: read permission is required to write into any file.
file can be edited and saved
3. -r-x
Note: read permission is required to execute any file.
shell (bash or sh, etc) will attempt to execute the file when file's name is entered as a command.

Directory Permissions:
1. dr--
content of directory can be read as ls.
Few examples:
$ ls testing/
ls: cannot access testing/file2: Permission denied
ls: cannot access testing/file1: Permission denied
file1 file2

Note: long listing requires execute permission.
Few examples:
$ ll testing/
ls: cannot access testing/file2: Permission denied
ls: cannot access testing/file1: Permission denied
total 0
-????????? ? ? ? ? ? file1
-????????? ? ? ? ? ? file2

2. d-wx
files may be created or delected in the directory.
Note:
a). execute permission required.
b). A file can be deleted by anyone who has write permission to directory in which the file resides regardless of the ownership or permission for that file.
Few examples:
a). $ ls testing/ [Failed]
ls: cannot open directory .: Permission denied

3. d--x
enter into directory using command cd
Few examples:
a). $ ls testing/
ls: cannot open directory testing/: Permission denied
b). $ cd testing/ [Okay]