This section is not encouraging hacking, cracking and spreading malicious codes:
it is about subjects worth knowing for serious computer users.

Introduction to Unix [ PDF file ]
Hacking Linux: Maintaining Access
Hacking Linux: Covering Your Tracks
Hacking Linux Part I: Privilege Escalation
Hacking Linux Part II: Password Cracking
Hacking Linux: What To Do Once You're Inside
Audit passwords with a password-cracking tool
Back up your boot sector
Back up your system with Mondo
Become familiar with runlevels
Write a CD before creating an ISO
Change Bash prompts
Change runlevels without rebooting
Chroot users to a specific directory with ProFTPD
Combine tools to monitor network traffic
Communicate with the talk client/server program
Connect to a remote machine using tightVNC
Using wildcards on the command line
Using tcpdump
Create audio CDs using MPG123 and cdrecord
Creating more than one subdirectory at a time
Customize Apache's default error pages
Debug Samba networks with smbclient
Deny an allow users in OpenSSH
VMS to Unix translation
Manage kernel modules
Don't overlook ext2's extended attributes
Download files more quickly using Bittorrent
Easily determine disk usage
Edit boot stanzas in Grub
Edit text with the vi editor
Ehnance Apache log files
Eliminate spam with bogofilter
Enable WebDAV in Apache 2.0
Encrypt the filesystem with BestCrypt
Exploring the grep command
Extend PAM's restrictions
Find files with slocate
Find system holes with chkrootkit
Find the suid files on your system
Format text with pr
Formatting the system date
Forward TCP ports to other machines
Get log statistics with AWStats
Get wireless network info with iwconfig
Brub challenges Lilo as top boot loader
A guide to Linux data compression
Counting with wc
How can you successfully restrict root logins?
Identify system information with /proc
View files using the head and tail commands
Improve RAS connection security
Increase web server security via obscurity
Burning video CDs with Linux
Introducing regular expressions
Keep DynDNS.org entries updated
Keep life simple: use aliases
Learn about LVM support in Linux
Learn how to resume suspended jobs
Learning Linux lingo: POSIX
Learn the many uses of netcat
Speeding up your Linux partitions
Linux skills review: locating files
Locating files
Look no further for a pure web browser
Usying rsync for remote backups
Maintaining passwords on a multiuser system
Maintain user accounts in large multiuser systems with ease
Manage kernel modules
Manage large file listings with xargs

Manage multiple jobs using these commands
Manage user groups
Manipulate filenames with ease
Monitor logs with LogSurfer+
Monitor network traffic with ngrep
Monitor processes with ps
Monitor your system with the top command
mv command options
Obtain system information with mrtg
Obtain system information with ucd-snmp
Operate on the results of the find command
Optimize PHP with APC
Password-protect Lilo
Using RSA/DSA keys in OpenSSH
Patrol log file events with simple WATCHdog
Perform file system validation with rpm
PHPEd 3.0 for Linux-based PHP developers
Using procmail to filter mailing lists
Quick keys in Emacs
Rotate system logs to save space
Run services using daemontools
Run two X sessions simultaneously
Run Windows applications on Linux
Run X within X
Using Nessus to scan your system
Schedule tasks with cron
Search for files with the find command
Search for rootkits with Rootkit Hunter
Secure bind with these tips
Security alert: Samba vulnerability
Select security levels using msec
Set priorities with nice
Setting up file sharing with NFS
Set up ethernet aliases
Setup RAID with mdadm
Share an Internet connection with multiple computers
Shut down unnecessary services
Solving Samba problems with Windows passwords
Solving the Samba/windows host gotcha
Speed up your hard drive!
Synchronize system time with clockspeed
Sync Linux data with a pocket PC
Track configuration changes with CVS
Understanding and using the mv command
Understanding bash startup files
Common files of the /etc directory and their uses
Update RPMs WITH urpmi
Upgrade to Linux Mandrake 9.2 with urpmi
Use ACLs with SGI's XFS file system
Use aide to verify data integrity
Use awk to format output
Use disk quotas for space restrictions
Use dlint to check DNS configuration
Use Firelogd to analyze your firewall
Use iptables to count bandwidth usage
Use keyboard shortcuts at the command line
Use keychain to simplify OpenSSH
Use lsof to find open files and ports
Use netstat to verify network connections
Use the Sylpheed e-mail client
Use Tripwire for integrity checking
Use vsftpd as a secure FTP server
Using colors with ls
Using cpg to download new signatures
Using mail for automatic messaging
Accessing remote CVS repositories
Administer Apache with the Apache toolbox
A guide to Linux data compression
Analyze Apace logs with Analog
Archiving commands in the Linux environment