S3ba’s Blog

Find and grep are two basic tools installed in all unix and unix-like systems. Every unix users or system administrator use frequently this two usefull and power tools. Here the links at two basic tutorial:

• Grep is a beautiful tool.
• Find is abeautiful tool.

To erase definitively all the data stored in an hard disk (floppy, pen drive, etc) the simple formatting is not enough, in fact is possible, with specified software, recover the "lost datas": this because the formatting or the process of deleting file don’t erase the file, but the link to hard disk sector where the effective file is stored, until this sector don’t be overwrite by another file.

Usually to way clean totally an hard drive is to write the drive with the pattern 0×00; in linux is possible to use the programm dd, an the command is:

# dd if=/dev/zero bs=4096 of=/dev/hdaX

 dd read in input the content of the device /dev/zero and write it in the destination device (/dev/hdax); the program read and write  4096 bytes at at time.

The MAC ADDREES (Media Access Controll Address) is the quasi-unique identifier attached to all networks adapter, for more info about MAC ADDRESS see here. Thus the Mac Address is the hardware address of a network adapter and associated with IP address in a LAN it identify a specific computer. As IP address, in linux is possible to change the MAC Address as follow:

• turn down the interface (ex. eth1):

# ifconfig eth1 down

• then set the new mac Address

# ifconfig eth1 hw ether 00:11:22:33:44:55

• verify the new address:

# ifconfig eth1

eth1      Link encap:Ethernet  HWaddr 00:11:22:33:44:55
             BROADCAST MULTICAST  MTU:1500  Metric:1
             RX packets:0 errors:0 dropped:0 overruns:0 frame:0
             TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
             collisions:0 txqueuelen:1000
             RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
             Interrupt:41 Base address:0xb000

•  now set again your interface: ip and routing table.

What is emacs: EMACS IS THE EDITOR.

Screnshoot of emacs editing perl program:

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webmin is web-based interface to manage unix system from web browser. Debian don’t have a webmin package in his official repository. To install webmin :

download the deb package from webmin homepage, and install with the command:

dpkg -i webmin_version.deb

OR

add the webmin repository in the sources.list of your debian:

deb http://download.webmin.com/download/repository sarge contrib

and then install the package:

apt-get update && apt-get install webmin

Then connect at webmin with your browser at: https://127.0.0.1:10000 and login as root.

Here some screenshots: