LQWiki - User contributions [en]

Network Neighbourhood

2010-06-20T19:01:50Z

Geek745: spelling, modernized, and added samba reference

'''Network Neighborhood''' is the [[Microsoft Windows]] name for a way/method to browse the [http://en.wikipedia.org/wiki/LAN Local Area Network]. "Network Neighborhood" has become "[[My Network Places]]" in Windows XP and "Computers Near Me" in Windows Vista and 7. The function remains the same.

== KDE Equivalent ==
in [[Konqueror]] (the [[File Managers|File Manager]] / [[Web Browsers|Web Browser]] used in [[KDE]] ) type:
lan://localhost
also:
fish://
and you should see a list of computers that your computers sees.

It isn't set up by default most of the time... so you will need to start the [[Services|service]] [[Lisa]]. KDE has a kcontrol part for setting up lisa, so it shouldn't be too hard to set up. You will need root access !

== Gnome Equivalent ==
In [[Nautilus]] type
smb://
to the address bar and your workgroup should pop-up.

== CIFS/Samba ==
Network Neighborhood uses the CIFS protocol for discovery of computers on the local network (as does [http://www.samba.org Samba]), so Samba can also be used to identify and communicate with other clients on the local network.

{{stub}}

[[Category:Networking]]

Partition a hard drive

2010-06-20T18:54:44Z

Geek745: add discussion link after stub flag

Warning: ''''Partitioning can ''DESTROY'' valuable data''''

Please read the [[partition]] and [[disk]]-related articles before coming here. By the time you start partitioning you should understand the difference between /dev/hdb1 and /dev/hdc.

In addition to [[cfdisk]] used in this example, you could use a graphical partition editor, Qtparted. To start [[cfdisk]], enter
<pre>
# cfdisk /dev/hdx
</pre>
where the 'x' in /dev/hdx is replaced by the disk you want to partition. To use [[fdisk]], leave off the 'c'.

Now you will see a screen that shows you your disk and how it is partitioned. Start by deleting the partitions you don't need. If there currently is only free space then you don't need to delete anything. You can move through the available actions with your left and right arrow.

Now it's assumed that you have deleted the partitions you didn't need. If you accidentally deleted something you shouldn't have press Ctrl+c and start from the beginning.

Now we will create new partitions. Partition 'design' is a matter of personal preference most of the time. On Desktop systems, you can get away with an absolute bare minimum of:
<pre>Primary Partition 1 /
Primary Partition 2 <swap></pre>

Server environments are also a matter of personal preference, but a starting point may be to have everything in one partition - this reduces the danger that you have plenty of space while one directories space is exhausted to the minimum.

== Vendor/OEM Partitioned Drives ==

Care should be taken when you are wanting to repartition a hard drive for Linux. If a vendor, like Dell or HP, setup the drive, it may have partitions or area where vendor specific information is contained. On some cheaper machines a partition contains the only copy of Windows that came with the machine.

'''First''' -- Check with the vendor that you can backup any vendor specific information. In some cases you can't. If you ever wanted to reload, you would have to resort to purchasing new OS media for the machine. You may also wipe out additional bloatware that the manufacturer may have shipped with the machine. For most, that is not an issue. But if you like the fancy card printing program that came with the machine, find a way to back it up - or order the program from another source.

'''Second''' -- Take care to note how the Master Boot Record is created. If you can back that up, then you should do so. Also note the original partitions and where they start and stop. What type of file system format do they follow. You never know when you will want to revert to the old software. Some restore CDs that came with the machine may abort if they find the machine configuration changed. Particularly with the partition table.

'''Third''' -- If you format the drive, be sure to do a sector by sector check for bad sectors. If you have a hard drive testing utility on a bootable CD then use it to test your drive. This is important on used equipment. If you have a factory machine, be sure that you don't void warrantee by removing the old software. The EULA can be a bear, always read the fine print.

== Planning Your Partitions ==
Linux installation programs usually will partition the hard disk to a preset size based on current machine memory, disk space availability, and usually partition the drive into two partitions, the Root "/" partition, and the Swap "/swap" partitions. With you the administrator/end-user being left out of the decision making process.

For those of you who are more adventurous, here are some ideas on how to partition your hard disk into something more fault tolerant, and more logical and safe.

When planning for partitions, plan in rough numbers. Always add more than you need to use. The number of users or the type of use (server, workstation, personal PC) do not dictate how to partition your hard drive. A number of install packages will do this automatically. However, if you are the heavy programmer, graphics user, pack-rat, or other large disk storage consumer, you will need to plan carefully, then multiply that number by a minimum of 1.5. Typically the multiplier is three times the estimated current needed amount.

Memory actually will impact how much disk space will be used for the operating system. Even as Windoz...er...Windows uses a certain amount of hard disk space for a swap area. In Linux/Unix, that area is static. It is not a file, but an entire partition to be used for one purpose - memory swap space. This is usually the only other partition you have to deal with other than the main Linux partition - IF you use the install package defaults.

With the main Linux partition, there are differences between the root partition "/" and "/boot", or other directories/partitions. Current versions of Linux/Ubuntu/Unix will now use a single partition to house everything. As an administrator, you may want to rethink that practice.

If you plan to have lots of downloads, news feeds, personal files, or source code, you will want to possibly partition the drives into more parts. This will protect the system partitions in the event of running out of space, or if you accidentally tried to format a partition (even as 'root'), or delete files (such as a 'find . -name -print -exec rm {} \;' and forget you are in the root directory of the particular partition.

'''Swap Partitions''' ( /swap )

Swap should be set to '''three times (3)''' or more of actual physical memory. If you want to load the OS and add memory later, it would be recommended that you add the memory first, before you edit the partition for swap areas. Older versions of Linux may not allow you to change the swap area size after you add more memory.

Set the swap space to three times the size as a default. Some would say to 1.5 to 2 times the size. But you never know when you have a hankering for a massive parallel build or want to run a gauntlet of programs.

If you add memory to your computer you may end up fighting the operating system errors until you resolve your swap space. Increase memory and you need to increase swap space. Some versions of Linux will not allow you to define a larger swap space than a pre-set amount. More administrator friendly versions will allow you to set the swap space to anything larger than 1.5 times the amount of physical memory. If you cannot set your swap larger than you want, think about how much you want to use, allocate the swap to the max Linux will allow, then allocate another area as additional swap space that can be mounted later, or added later via repartitioning.

'''Boot Partition''' ( /boot )

With today's hard disk drives in the 120 Gig range and higher, you can allocate two or three gigs to this area. This will be useful when rebuilding kernels and wanting to keep different versions of kernels available. having a separate /boot also allows for protection against full disk problems. (See more below)

'''Root partition''' ( / )

The root partition should contain at least: /, /bin, /usr, /lib, /mnt or /media, /dev, /proc, and other directories that are critical to operating the system during boot process or in single user/maintenance mode. Usually these are static areas for programs that the operating system uses, or for applications that rarely change. Storage for mail, news, web, or other dynamic data functions should be avoided in these areas. The risk of file erasure or space issues may pose a problem in the future. Even if you think you have enough storage now, there is always the 'later' to think about.

'''/var''' use to stand for "Value Added Retailer" storage area. Now is has become "various" storage. Under this should be your programs that are not critical to the operating of the computer in a critical situation. Games, added applications, development programs, and some X11 programs should reside here.

'''/home''' is a directory where, on most versions of Linux and Unix, the user home directories are stored. Sometimes some of the administrative login areas are stored here. Should an administrative login have a location in /home, it is recommended that you move it to a directory under the root partition. This way you will have it available during single user mode maintenance. If you are going to use your system as a server, or you plan to do a LOT of heavy graphics, database work, or programming, you should allocate LOTS of disk space for this directory.

== See also ==
* [[Partitioning]]

{{stub}} ([[Talk:Partition_a_hard_drive|discuss here]])

Talk:Partition a hard drive

2010-06-20T18:51:48Z

Geek745:

Anyone object to pulling the stub flag from this? [[User:Geek745|geek745]] 18:51, June 20, 2010 (UTC)

Talk:Partition a hard drive

2010-06-20T18:51:21Z

Geek745: stub?

Anyone objection to pulling the stub flag from this? [[User:Geek745|geek745]] 18:51, June 20, 2010 (UTC)

Talk:Shadow

2010-06-20T00:32:40Z

Geek745: edit comment

Thanks, [[User:ThorstenStaerk]] for the correction, reducing "incredibly secure" to "secure" at [http://wiki.linuxquestions.org/index.php?title=Shadow&diff=0&oldid=53034] [[User:Geek745|geek745]] 00:32, June 20, 2010 (UTC)

Shadow

2010-06-19T22:38:52Z

Geek745: bunch of additions

The '''shadow''' file (/etc/shadow) stores passwords and expiry dates in [[encrypted]] form in a colon-delimited text file akin to /etc/passwd - which formerly held unencrypted passwords and now contains all kinds of information about users ''except'' the password.

== Password Security ==
Passwords are stored in the shadow file in an incredibly secure manner, not only using a cryptographically-secure hash (one-way) function, but further adding to the uniqueness of the hash by a method called salting. A combination of the time the password was created, as well as the process ID (pid) of the process generating the hash are concatenated to the user's password before hashing, and then stored separately, in order that they might be used during authentication.

This protects against users determining that other users' passwords are the same as theirs by virtue of an identical hash. It also protects against rainbow tables' effectiveness in cracking these passwords by increasing the complexity of the process of both generating and using the results of rainbow tables.

== Authentication ==
When a user attempts to log into the system, the salt (time and pid, as above) are first concatenated to the password provided by the user, then hashed with the same function, and the computed value compared to the one stored in the shadow file. If they match, the login is successful.

== Tips ==
This should '''not''' be readable by a regular user. If a user can see this file, they can copy your password hashes, and attempt a brute force crack. Permissions should be something like:

-rw-r----- 1 root shadow size date /etc/shadow

or

-rw------- 1 root root size date /etc/shadow

==See also==
* [[Security]]
* [[User Commands]]

== External Links ==
[http://linux.die.net/man/5/shadow shadow(5) manpage]

''This article is a [[LQWiki:stub_articles|stub]] and needs to be finished. [[LQWiki:plunging_forward|Plunge forward]] and [[LQWiki:How_to_edit_a_page|help it grow]]!''

Router

2010-06-19T22:25:26Z

Geek745: grammar; re-order content

A '''router''' is a networking device which operates at layer 3 of the [[OSI Model]]. Its purpose is to switch data packets between its various interfaces based upon the destination IP address of the packet.

Routers are intelligent devices and can make decisions about which route a packet can take through a network if there are multiple paths possible. The decision about which path to take is made from a link's cost which is calculated from the factors of bandwidth, [[hop count]], financial cost, load, delay and reliability.

Many routers also provide a service known as [[NAT|Network Address Translation]] or NAT.

It should also be pointed out that from a security point of view, if you have a router, then every computer behind it is protected from attack from the other side (i.e. the internet). However, this does not protect you from accessing viruses or other malware on the Internet and infecting your machine with them. It only protects against direct attack from the other side of the router.

Most Linux [[distributions]] come with routing support allowing your Linux machine to operate as a router if it has one or more [[NIC]] installed.

''This article is a [[LQWiki:stub_articles|stub]] and needs to be finished. [[LQWiki:plunging_forward|Plunge forward]] and [[LQWiki:How_to_edit_a_page|help it grow!]]''

= See also =
* [[netWorKing]]
* [[hardwAre]]

[[category:Networking]]
[[category:Hardware]]

Ports (package management system)

2010-06-19T22:19:03Z

Geek745: longer description; other platforms

'''Ports''' is a package management system used in [http://en.wikipedia.org/wiki/BSD BSD] [http://en.wikipedia.org/wiki/Operating_system operating systems].

== Description ==
Ports is a source-based package management system that queries the server and updates a local database describing each package and its current version, as well as tracking the installation history of packages installed using Ports. A user may refresh his ports database, upgrade all installed packages to their latest versions, add new packages, and remove installed packages from his system.

When adding new packages, the Ports system will download the appropriate source code, including any dependencies, build them in the proper order, and install the resulting binaries and documentation into the system tree, tracking the whole process for reversal and/or upgrade at a later date.

== Other platforms ==
* [http://www.gentoo.org Gentoo]'s portage system is inspired by BSD Ports.
* [http://www.macports.org MacPorts] is an Apple OS X (DarwinBSD derivative) that provides many popular GNU/Linux applications in an Apple-friendly Ports-like system.

== External links ==
* [http://www.netbsd.org/ NetBSD] (''www.netbsd.org'')
* [http://www.openbsd.org/ OpenBSD] (''www.openbsd.org'')
* [http://www.freebsd.org/ FreeBSD] (''www.freebsd.org'')

{{stub}}

At

2010-06-19T22:11:36Z

Geek745: added atq and atrm

The '''at''' service allows a command-line task to be executed at a specified future time. Unlike the [[cron]] service, '''at''' commands are only executed once, and cannot be scheduled to run at a recurring interval.

The '''at''' service is controlled by the [[atd]] [[daemon]] and is installed by default in most distributions.

= How to use =
* General usage: '''at''' time date - '''at''' HH:MM MM/DD/YY - '''at''' 12:15 PM today - '''at''' 12:15 tomorrow
* Times and Dates are accepted in several formats 02/01/09 or 02.01.09 - 4:00 pm or 16:00
* When you enter '''at''' with a time and date, you then see the '''at''' prompt at>. Enter the commands you want executed, and when done, with your cursor at the beginning of a new line, do a ctrl-d
$ at 12:15
at> echo "i like linuxquestions.org"
at> ctrl-d
at> <EOT>
job 17 at Tue Aug 11 12:15:00 2009
* '''at''' assumes 'tomorrow' if it is already past the time given and you do not include a date
* The same could be executed by typing:
echo "i like linuxquestions.org" | at 12:15 tomorrow
* Using numbers and units
Execute command at this time, 1 week from now
at now + 1 week
4 am 3 days from now
at 4:00 am + 3 days

= View Scheduled Jobs =
Use the -l option to list the at-queue. Also use the command atq:
at -l
atq

= Remove Scheduled Jobs =
Use the -d option to remove jobs from the at-queue. Also use the command atrm:
at -d <jobid>
atq <jobid>

= See also =
* [[cron]]
* [[atd]]
* [[command]]

= External Links =
* [http://en.wikipedia.org/wiki/Daemon_(computer_software) wikipedia.org : Daemon]
* [http://man-wiki.net/index.php/1:at at man page]

{{stub}}
[[category:Command]]

User:Geek745

2009-01-18T21:39:34Z

Geek745: /* Paul M. Nguyen */

== Paul M. Nguyen ==

Welcome to my LQ Wiki user page!

Check out my blog: [http://penguinsrus.blogspot.com Penguins 'R' Us]

User talk:Geek745

2009-01-18T21:38:16Z

Geek745: first edit.

Welcome! Let's chat. [[User:Geek745|geek745]] 21:38, January 18, 2009 (UTC)

User:Geek745

2008-09-19T06:47:04Z

Geek745: Initial content

=== Paul M. Nguyen ===
Welcome to my LQ Wiki user page!