Linux Directory Structure Explained with diagram

Friday, July 18, 2014

Have you wondered why certain programs are located under /bin, or /sbin, or /usr/bin, or /usr/sbin?
For example, less command is located under /usr/bin directory. Why not /bin, or /sbin, or /usr/sbin? What is the different between all these directories?
In this article, let us review the Linux filesystem structures and understand the meaning of individual high-level directories.

1. / – Root

• Every single file and directory starts from the root directory.
• Only root user has write privilege under this directory.
• Please note that /root is root user’s home directory, which is not same as /.

2. /bin – User Binaries

• Contains binary executables.
• Common linux commands you need to use in single-user modes are located under this directory.
• Commands used by all the users of the system are located here.
• For example: ps, ls, ping, grep, cp.

3. /sbin – System Binaries

• Just like /bin, /sbin also contains binary executables.
• But, the linux commands located under this directory are used typically by system aministrator, for system maintenance purpose.
• For example: iptables, reboot, fdisk, ifconfig, swapon

4. /etc – Configuration Files

• Contains configuration files required by all programs.
• This also contains startup and shutdown shell scripts used to start/stop individual programs.
• For example: /etc/resolv.conf, /etc/logrotate.conf

5. /dev – Device Files

• Contains device files.
• These include terminal devices, usb, or any device attached to the system.
• For example: /dev/tty1, /dev/usbmon0

6. /proc – Process Information

• Contains information about system process.
• This is a pseudo filesystem contains information about running process. For example: /proc/{pid} directory contains information about the process with that particular pid.
• This is a virtual filesystem with text information about system resources. For example: /proc/uptime

7. /var – Variable Files

• var stands for variable files.
• Content of the files that are expected to grow can be found under this directory.
• This includes — system log files (/var/log); packages and database files (/var/lib); emails (/var/mail); print queues (/var/spool); lock files (/var/lock); temp files needed across reboots (/var/tmp);

8. /tmp – Temporary Files

• Directory that contains temporary files created by system and users.
• Files under this directory are deleted when system is rebooted.

9. /usr – User Programs

• Contains binaries, libraries, documentation, and source-code for second level programs.
• /usr/bin contains binary files for user programs. If you can’t find a user binary under /bin, look under /usr/bin. For example: at, awk, cc, less, scp
• /usr/sbin contains binary files for system administrators. If you can’t find a system binary under /sbin, look under /usr/sbin. For example: atd, cron, sshd, useradd, userdel
• /usr/lib contains libraries for /usr/bin and /usr/sbin
• /usr/local contains users programs that you install from source. For example, when you install apache from source, it goes under /usr/local/apache2

10. /home – Home Directories

• Home directories for all users to store their personal files.
• For example: /home/john, /home/nikita

11. /boot – Boot Loader Files

• Contains boot loader related files.
• Kernel initrd, vmlinux, grub files are located under /boot
• For example: initrd.img-2.6.32-24-generic, vmlinuz-2.6.32-24-generic

12. /lib – System Libraries

• Contains library files that supports the binaries located under /bin and /sbin
• Library filenames are either ld* or lib*.so.*
• For example: ld-2.11.1.so, libncurses.so.5.7

13. /opt – Optional add-on Applications

• opt stands for optional.
• Contains add-on applications from individual vendors.
• add-on applications should be installed under either /opt/ or /opt/ sub-directory.

14. /mnt – Mount Directory

• Temporary mount directory where sysadmins can mount filesystems.

15. /media – Removable Media Devices

• Temporary mount directory for removable devices.
• For examples, /media/cdrom for CD-ROM; /media/floppy for floppy drives; /media/cdrecorder for CD writer

16. /srv – Service Data

• srv stands for service.
• Contains server specific services related data.
• For example, /srv/cvs contains CVS related data.

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How to find a remote IP

Wednesday, January 30, 2013

Method 1
To view someone's IP# when they send you hotmail email do this:
1) Click "Options" on the upper right side of the page.
2) On the left side of the page, Click "Mail"
3) Click "Mail Display Settings"
4) Under "Message Headers" select "Full" or "Advanced"
5) Click ok

Method 2
reg a dydns account and install the ip pointer, so each time you ping the host name you regestored

for example:
you regestor the host name myhost.dydns.com, then you keep a little software running on the target host. The little software will keep update your IP to dydns.com server.

so at your pc just start cmd, and ping myhost.dydns.com, it will give you the most updated ip address.

Method 3
neverender, what doesn't work for you? Simply type in nc -vvv -l -p 80 on your box, which will set it to listen in verbose mode on port 80. Then give them a link to your IP address (for example: 111.111.111.11) and tell them to type it in their browser. The browser should resolve the address as well as append port 80 automatically. Just make sure that your friend is not very computer literate.

Method 4
Just download a very simple server such as this one and install it on your comp. Then run it and give your ip to the person you want and tell them to connect to it through a browser. Your server will log their connection and you will get their IP.

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Free Download Cisco Packet Tracer 5.2 with Serial Key

Monday, January 28, 2013

 Packet Tracer 5.2 with Serial Key

Cisco Packet Tracer is a powerful network simulation program that allows students to experiment with network behavior and ask “what if” questions. As an integral part of the Networking Academy comprehensive learning experience, Packet Tracer provides simulation, visualization, authoring, assessment, and collaboration capabilities and facilitates the teaching and learning of complex technology concepts.

Packet Tracer supplements physical equipment in the classroom by allowing students to create a network with an almost unlimited number of devices, encouraging practice, discovery, and troubleshooting. The simulation-based learning environment helps students develop 21st century skills such as decision making, creative and critical thinking, and problem solving. Packet Tracer complements the Networking Academy curricula, allowing instructors to easily teach and demonstrate complex technical concepts and networking systems design.

DOWNLOAD LINK:

Packet Tracer 5.2 with Serial Key

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Top 5 Best Linux OS Distributions

Monday, December 3, 2012

1. Ubuntu

2. Debian

3. Fedora

4. CentOS

5. Red Hat

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About Windows Server 2012

Windows Server 2012, formerly codenamed Windows Server 8, is the current release of  Windows Server. It is the server version of  Windows 8 and the successor to Windows Server 2008 R2.

Unlike its predecessor, Windows Server 2012 has no support for Titanium-based computers, and has four editions. Various features were added or improved over Windows Server 2008 R2, such as an updated version of Hyper-V, an IP address management role, a new version of Windows Task Manager, and the new ReFS file system.

Originally, Microsoft referred to their new server operating system as "Windows Server 8".

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