Wikipedia:Reference desk/Archives/Computing/2008 June 20

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June 20

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Donations in website

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I would like to setup a donations page on my website, is there any service to recieve money easily, and that does not require a credit card? I would like to to get a paypal account but i think a credit card is required, is this right? how about alternative services? any help is appreciated.... thanks SF007 (talk) 00:36, 20 June 2008 (UTC)[reply]

Been a while but last I looked, PayPal didn't require a credit card. You could set up an account and have any money from your PayPal account transferred into your checking account. Dismas|(talk) 01:04, 20 June 2008 (UTC)[reply]
Guess they didin't require a credit card, I already created an account... thanks. SF007 (talk) 16:13, 21 June 2008 (UTC)[reply]
Take a look at Amazon.com honor system. [1] You get the benefit of their patented 1-Click® technology! Yay! Another trivial software patent! NoClutter (talk) 16:57, 23 June 2008 (UTC)[reply]
Yeah, "patented"... thanks anyway, I might try it... SF007 (talk) 23:54, 24 June 2008 (UTC)[reply]

Cost of a parked domain...

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How do you guys think an already registered and parked domain will cost? I know it depends a from lots of things but... could you give an estimate? I think it is not a very profitable one... (like utube or something, see what I mean?) It is parked with godaddy.com ads ("This page is parked free, courtesy of GoDaddy.com")... Could someone give me an estimate? I know it's hard but... 20$, 50$, 100$? a lot more? I'm a little in the dark regarding this... Thanks SF007 (talk) 01:49, 20 June 2008 (UTC)[reply]

I would say USD 10 to USD 50 per year.
I was referring to just buy the domain from the current owners... not the rest... but thanks anyway. SF007 (talk) 15:42, 20 June 2008 (UTC)[reply]
You could just click on the GoDaddy notice. If you get web hosting from GoDaddy for the website, they might lower (or even drop) the cost of the domain. All you need to do to find out is to talk with GoDaddy. Kushal (talk) 18:27, 20 June 2008 (UTC)[reply]
Nah, I don't host with them, I already contacted my web hosting company and they tried to reach the current owners... I'm still waiting... they might not even want to sell... I' guess I'll just have to wait... SF007 (talk) 16:12, 21 June 2008 (UTC)[reply]
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I read that Spore is going to have some crazy copyright protection system that messes with your computer instead of just requiring a simple activation. Is this true? I want to play Spore but I don't want to screw up my new computer. —Preceding unsigned comment added by 71.175.124.109 (talk) 02:07, 20 June 2008 (UTC)[reply]

See Spore_(video_game)#Digital_rights_management. It's a form of SecuROM. It's not crazy, but yeah, it's DRM, and it is a bit dubious. --98.217.8.46 (talk) 01:24, 21 June 2008 (UTC)[reply]

HTML code

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Is there any HTML code that gives more space than say   or
? Thanks, Ζρς ι'β' ¡hábleme! 02:55, 20 June 2008 (UTC)[reply]

Um,   or


perhaps? --Kjoonlee 04:07, 20 June 2008 (UTC)[reply]

He wanted to say: Um, <span style="padding-left:10em;padding-right:10em">&nbsp;</span> or <div style="padding:3em"><br /></div> perhaps? --Constructor 04:40, 20 June 2008 (UTC)[reply]
Ah, yes. I like it. Thank you, Ζρς ι'β' ¡hábleme! 20:35, 20 June 2008 (UTC)[reply]

Freeware time changer.

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i need a software that will keep my system(pc) time constant in order to keep my system safe from time activated virus. is there any freeware/shareware software that wiil keep my system time and date constant? —Preceding unsigned comment added by Shamiul (talkcontribs) 03:09, 20 June 2008 (UTC)[reply]

Are you aware that if you do this, you won't be able to do automatic scheduled backups or get meaningful ETAs for downloads, which may be worse than the damage the virus would cause? I suggest that anti-virus software would probably be better. NeonMerlin 04:11, 20 June 2008 (UTC)[reply]

i'm fully aware! anti-virus tend to slow pc; especially old pc like mine. please inform me if i can do this by editing registry without using any software. —Preceding unsigned comment added by Shamiul (talkcontribs) 04:40, 20 June 2008 (UTC)[reply]

You could have an antivirus program that does NOT provide realtime protection (like Clamwin) if you want to. Just keep it updated scan your entire system at least once a week, scan incoming files before opening them etc. It is not recommended to have a Windows computer with no protection. Kushal (talk) 05:03, 20 June 2008 (UTC)[reply]
Try one of these. Copypaste into a file.cmd (or .bat) and launch.
If you use Windows NT/2000/XP:
:q
@echo %time%|time>nul&goto q
For Win 98:
:q
@time /t|time>nul
@goto q
If that doesn't work...
:q
@echo 13:37|time>nul
@goto q
--grawity 11:25, 20 June 2008 (UTC)[reply]

Time-activated virus? This is really not as big a threat to your PC as you might think. Waste of time (so to speak) to try and do this. Just get a lightweight anti-virus scanner. --98.217.8.46 (talk) 11:41, 20 June 2008 (UTC)[reply]

Even if you do have one of the rare "time activated" viruses, it will probably be slowing down your PC significantly as it tries to reproduce itself as much as possible before the 'go date'. APL (talk) 17:46, 20 June 2008 (UTC)[reply]

You may also want to think about switching to Linux. Linux tends to run better on older systems and be better supported than pre-2000 versions of Windows, and viruses for Linux are extremely rare. NeonMerlin 22:21, 20 June 2008 (UTC)[reply]

If you take NeonMerlin's advice and switch to Linux I'd personally recomend Ubuntu the laterst version is here or for a light antivirus software for windows use ESET. Xor24 talk to me 16:30, 22 June 2008 (UTC)[reply]

MySQL vs. PostgreSQL: Inheritance

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Does MySQL suffer from the same limitations of inheritance as PostgreSQL, with respect to constraints? NeonMerlin 04:07, 20 June 2008 (UTC)[reply]

Does MySQL even have inheritance? I see no mention of it here. --Sean 14:59, 23 June 2008 (UTC)[reply]

Magsafe

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1. I'm assuming the Magsafe patent has been granted. Why wasn't it disqualified as prior art? 2. When will the patent expire? Thanks in advance, --MagneticFlux (talk) 05:52, 20 June 2008 (UTC)[reply]

I would assume there was some kind of confidential agreement between the fryer company and Apple Computers, Inc. The application was published on March 29, 2007uspto. I would assume it does not expire until after 2027. However, I could be wrong. It leaves a bitter taste in my mouth when thinking Apple would need to file a patent for such a useful thing (the legitimacy of the patent is another question, which I believe Apple has probably resolved in private). However, this is how the patent system works. Unless one has a large enough portfolio, expanding from A to Z so that one can countersue the entity (or partner entities) who charges (or threatens to charge) one with patent infringement. In this way, one would (hopefully) not have to pay up for patent infringements. Of course, in the real world, there are patent trolls among other problems. Therefore, even if one supports the idea of patents, (s)he must agree that the system is far from perfect. Kushal (talk) 18:24, 20 June 2008 (UTC)[reply]
Sadly, it seems that you can take any existing invention, tack on "... but this time with a computer!", and the USPTO will accept it as novel. --Sean 15:04, 23 June 2008 (UTC)[reply]

PSXEven: More help

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I fixed the speed problem in PSXEven and the games worked properly, but now I am getting another problem with PSXEven: I keep getting a general protection fault when I try to start a game. How can I fix this? Interactive Fiction Expert/Talk to me 05:57, 20 June 2008 (UTC)[reply]

Sometimes one can get around general protection faults if setting compatibility mode if you use Windows XP. --Constructor 06:08, 20 June 2008 (UTC) PS: This is a general advice which may or may not work with PSXEven. --Constructor 06:10, 20 June 2008 (UTC)[reply]
Didn't work. Please give another solution. Interactive Fiction Expert/Talk to me 10:48, 20 June 2008 (UTC)[reply]
How about : "Use a diferent emulator, one in active development with an active support forum where you can ask questions."
or : "Go buy a playstation. (I just checked "completed auctions" and Ebay often has Australian Playstations for as little as $10AU. )"
or : "Ask questions in such a way that they contain enough information to actually answer them without resorting to wild guesses."
or : "Be civil and polite on the RefDesk so that people may be more inclined to help you without prefacing their answers with smart-ass remarks like this one."
But seriously, you don't mention if it happens with every game or just one. If it's just one then I'd assume that that one game is not compatible with the emulator, or one of the plug-ins you're using. (Do not trust computability lists.) You might try it with different plug-ins, (and disable the ones that aren't absolutely necessary like the sound.) If the emulator previously worked, then suddenly it didn't work, then something has been screwed up. Likely a plug-in setting. It sounds ridiculous, but if you can't figure out what you changed to make it break, I recommend just deleting it and then reinstalling it. Emulators can be pretty touchy.
Hope this helps. APL (talk) 17:43, 20 June 2008 (UTC)[reply]

I've had problems with ePSXe. First, I think the versions have incompatibilities. Get another version and see if that works. I have 1.6 and 1.5.2, because some games will only work on one. The best solution is to use PSX, which I've had much better luck with. JeremyMcCracken (talk) (contribs) 04:03, 21 June 2008 (UTC)[reply]

Mozilla 1.6 mail confusion

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The mail component of Mozilla 1.6 (uh, yes, a little old I know; 2004) running under Mac OS X is giving error messages about having no space. The hard drive has 11GB of space. The inbox is about 2GB, whereas I'd expect it to be well under 10MB now that most of the mail ever received is in a subdirectory (which is 200MB or so). And there are various other oddities I shan't bore you with.

Would it be better

  1. to try to fix the mess and then install a new Thunderbird on top, or
  2. to leave diagnosis and repair to the new Thunderbird, or
  3. to run some program that repairs mailboxes

?

The third sounds appealing, but what program is there?

If the first: My uneducated guess is that Trash or Trash.msf or their combination has somehow got corrupted. I'd guess again that Mozilla does elementary error checking when it starts up and if it doesn't find one or both of these then it automatically generates it/them. If I'm right, I could then simply delete the putatively corrupt Trash and Trash.msf and have Mozilla make new ones. But I fear that I could be wrong and that this superduper idea of mine might totally cuff up the missus' mail archive. Suggestions? -- Hoary (talk) 08:50, 20 June 2008 (UTC)[reply]

Have you found any option within Mozilla to rebuild or compact your mailboxes? Unfortunately I am unfamiliar with your program, but I believe Mail.app has such functionality and other programs might as well. If you decide to delete possibly-corrupt files, make a backup first. Installing Thunderbird seems like a low-risk strategy. See if it can successfully import the Mozilla mailboxes. If it can, problem solved and you have a new mail client. If it can't, should be no harm done, as the import process should not modify your original files, I don't think. Fletcher (talk) 13:29, 20 June 2008 (UTC)[reply]
Thank you! And I hope that this page will provide a solution for the un-compactable 1.9 GB inbox. -- Hoary (talk) 14:34, 20 June 2008 (UTC)[reply]

Buying Digital camera

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I am considering to buy a digital camera (in Europe), what brands do you think are the best? I can spend up to 140-150 euros (about 217-232 dollars) I would like some features, but don't need too advanced ones... And of course i would like a good image quality... Some sony cybershots seemed cool... but they don'y support xD cards, the ones I have, something that would also be cool, but not essential... what do you suggest? thanks. SF007 (talk) 14:01, 20 June 2008 (UTC)[reply]

I suggest looking at dedicated review sites such as Steve's Digicams and DP Review where you'll get details from experts. --LarryMac | Talk 14:26, 20 June 2008 (UTC)[reply]
I like my three-year-old Fuji, which I think is called F11. Recently I bought an Olympus wonder, new:: the Olympus has higher resolution but the old Fuji gives better results (less grainy in the dark, and it has a clue about white balance, whereas the Olympus makes spectacularly bad guesses). The Olympus is prettier but the Fuji has better ergonomics. Although I paid €350 or something for the Fuji when it was new, I'm sure that a used example would come within your budget. -- Hoary (talk) 14:41, 20 June 2008 (UTC)[reply]
I'm advertising the fuji s5700 or s5800 - takes sd and xd cards, has an electronic viewfinder, macro, wide angel and zoom, as is just at the top end of your price range.. The sony (and panasonic lumix) cameras could be considered overpriced - but if you want 'cool' it's usually necessary to pay extra.87.102.86.73 (talk) 16:31, 20 June 2008 (UTC)[reply]
Please try to stay away from xD card ONLY cameras unless you find one for an exceptionally good price (FREE). Kushal (talk) 18:05, 20 June 2008 (UTC)[reply]
Let me point out that the Olympus SP-570 UZ is an exceptionally good bridge camera that unfortnately only takes xD cards, can I have my free one now. 87.102.86.73 (talk) 21:00, 20 June 2008 (UTC)[reply]

I wouldn't recommend a Vivitar Vivicam $20 model. They're $20 for a reason. JeremyMcCracken (talk) (contribs) 03:56, 21 June 2008 (UTC)[reply]

Thanks very much to you all. I ended up buying an Pentax Optio E50, and it seems to be a good machine, as far as I could tell for the few hours i've used it... (140 euros/218 dollars for: the camera + 2 rechargable batteries + 2 non-rechargable batteries + a battery recharger + a nylon case + 1 GB SD memory card... WOW I think I made a very good deal...) thanks again. SF007 (talk) 16:00, 21 June 2008 (UTC)[reply]
Bit late to the party but in case anyone else finds this useful I would also recommend you stay away from amy MemoryStick only cameras Nil Einne (talk) 19:56, 22 June 2008 (UTC)[reply]

Analog passthrough on CECB

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How does this feature work on the Zenith DTT901 digital-to-analog TV converter box ?

1) Does the analog signal only come out the coax output, or also out the RCA outputs (yellow, white, and red cables) ?

2) Do you need to select analog output on the remote or is it always produced whenever the CECB is on ? How about when it's off ?

These two seem related, as the coax output can send multiple frequencies at once, but, as far as I know, other outputs only produce a single frequency at a time. StuRat (talk) 16:04, 20 June 2008 (UTC)[reply]

Analog pass-through is only relevant if you're connecting the CECB to your TV via a coax cable. Analog pass-through means you can turn off the CECB, then change channels on your TV and still receive analog channels from your antenna: The CECB passes the antenna signals from the antenna input jack through to the RF output jack. You don't need to activate any setting for this. But when the CECB is on, it will transmit its own picture on channel 3 or 4, and this will override or interfere with the analog signals from the antenna. --Bavi H (talk) 02:55, 21 June 2008 (UTC)[reply]
I couldn't find a manual for the Zenith DTT901. But the Apex Digital DT250 User's Manual clearly describes analog pass-through on PDF page 10 (printed page 9). Other CECBs that support analog pass-through will likely be the same. --Bavi H (talk) 03:05, 21 June 2008 (UTC)[reply]

Thanks. If it helps the research any, it's twin model is the Insignia NS-DXA1-APT. StuRat (talk) 15:48, 21 June 2008 (UTC)[reply]

Well, I went a bought one, so can now answer some of my own questions:

1) As we thought, the analog pass-through only comes through the coax output.

2) There's no selection for analog pass-through. It appears to occur whether the CECB is turned on or off. However, if the CECB is on, expect some interference, especially on channels adjacent to channel 3 or 4 (whichever is selected for the coax digital output).

And, in case anyone is curious, Zenith appears to have solved the issue with low volume output when set to stereo mode (this was a problem on their previous DTT900 model). It now provides the same volume as when it's set to mono output. StuRat (talk) 06:56, 26 June 2008 (UTC)[reply]

HTML question

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I have a side menu on a web page. It's in a frame. I'd like there to be a background image in that frame but I don't want it to start at the top. I want it moved down 32 pixels and then repeat from there. The background image is 165x420. Is there someway to change valign to do this? Right now, I have:

<td width=165 height=420 valign=top align=center background="/images/voravert.gif" bgcolor="#FFFFFF">

Suggestions? Dismas|(talk) 16:55, 20 June 2008 (UTC)[reply]

This is best done with a cascading style sheet. See http://www.w3.org/TR/CSS21/colors.html --Prestidigitator (talk) 17:27, 20 June 2008 (UTC)[reply]
Dismas is suggesting replacing background="..." with something like: style="background: #ffffff url(/images/voravert.gif) top left no-repeat;". In this case, that might not do all you want it to - you could use this: style="margin-top: 32px;" which will also move any text in that box down 32 pixels. See w3schools for more on CSS stuff. --h2g2bob (talk) 00:44, 21 June 2008 (UTC)[reply]

FLAC in an .ogg file

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I understand FLAC audio can be wrapped in an .ogg file container. Do any tools for Linux exist to do this? NeonMerlin 17:59, 20 June 2008 (UTC)[reply]

Download the software for you version of Linux from flac.sourceforge.net, or compile it from source code, then run the command-line tool with the --ogg option, for example "flac --ogg imput.wav" and you should get a FLAC stream wrapped in an ogg transport layer. It will have a .ogg extension but will still be decodable by flac. JessicaN10248 20:11, 20 June 2008 (UTC)[reply]

Mozilla Firefox Searchbar: Lost add-ons

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I'm trying to find two add-ons for my Firefox Search Bar: --The first is a function that automatically clears the search field after a search is conducted. Immediately after clicking on the magnifying glass icon, or after hitting "Enter" or "Alt-Enter," the search terms are automatically wiped out. --The second function automatically expands the size of the search field in accordance with the length of the given search term(s). After a search is initiated, it reverts back to a standard, shorter length, thus maximizing space. Because I've had these add-ons in the past, I know they exist. However, I am currently unable to find them. I don't remember if these are 'official' Firefox add-ons or if they're simply modifying software developed and released elsewhere. I've tried a variety of searches/search terms to attempt to find these add-ons. I'm currently using Mozilla Firefox version 2.0.0.14. Please help. Lulletc (talk) 18:09, 20 June 2008 (UTC)[reply]

You are looking for this: https://addons.mozilla.org/en-US/firefox/addon/1172. This addon performs both the functions you mention. Mike R (talk) 21:09, 20 June 2008 (UTC)[reply]
That's *exactly* what I'm looking for. Thanks, Mike R. Tell Mike call me. Lulletc (talk) 21:39, 20 June 2008 (UTC)[reply]
If I must. Mike, would you please call this user?--The Fat Man Who Never Came Back (talk) 22:39, 20 June 2008 (UTC)[reply]
I can but I will not. Mike R (talk) 05:39, 21 June 2008 (UTC)[reply]

Router - Port forwarding problems

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I have downloaded some software (ShoutCast) that lets me broadcast streaming audio, using my PC as the server, however it is not working because my router will not direct the port to the right PC.

I have two PCs connected to the router, their IP addresses appear as 192.168.1.2 and 192.168.1.3 (the router itself is 192.168.1.1). I have tried accessing the Shoutcast web page that is supposed to be located at xxx.xxx.xxx.xxx:8000 but it doesn't work, obviously the router does not know which machine to send the request to.

I have gone into the Port Forwarding section of my router's config system and tried setting up a new 'rule', the fields and their current contents are below:

Connection: Connection1 (the name of my connection to the WWW)
Source IP address: Not sure what this should be
Source netmask: 0.0.0.0
Destination IP address: 192.168.1.3 (the IP address of the computer running the Shoutcast server)
Destination netmask: 255.255.255.255
Destination port start: 8000
Destination port end: 8001
Destination port map: 8000

The port Shoutcast broadcasts on is definitely 8000. It is not a LAN problem as I can access the stream by typing in 192.168.1.3:8000 but not when typing in the real IP address of the router.

I do have a static IP address provided by my ISP and I used to use Shoutcast fine before I got a router. Do I need to set anything up in the router to make it realise it is being used as a static IP address? If so, what do I need to do? The router is an Addon GWAR3000. I know what the IP address is but that is the only detail I have been given by my ISP, I do not know what to put for gateways and netmasks and all that sort of thing. If I type my IP address into a browser then the router config page comes up so the IP address setup is OK presumably.

Thanks in advance for any help. —Preceding unsigned comment added by 62.249.220.179 (talk) 19:27, 20 June 2008 (UTC)[reply]

I just tried going to your IP address port 8000 ([2]), and it seems to be working now. JeremyMcCracken (talk) (contribs) 03:59, 21 June 2008 (UTC)[reply]
Hmmn yes I just tried to connect to it and it said page cannot be displayed. Does it work now? —Preceding unsigned comment added by 62.249.220.179 (talk) 08:13, 21 June 2008 (UTC)[reply]
Yes, I'm getting a Shoutcast administrator page. JeremyMcCracken (talk) (contribs) 03:06, 22 June 2008 (UTC)[reply]

Thunderbird spam filters

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Thunderbird is doing a reasonable job at figuring out which emails I get are spam. Well, there are very, very few false positives and an acceptable level of false negatives. What I would like to do is get TB to just delete the damn spam mails and let me look at the ones it deems safe. Flagging them just seems pointless. Is there a way to get TB to either delete from the server or (preferably) move to trash automatically? Matt Deres (talk) 19:44, 20 June 2008 (UTC)[reply]

What version of Thunderbird and what Operating System? The menus are not the same in all versions. However, Thunderbird has always had the option of which folder to move junk mail to. You can send it straight to the trash folder. -- kainaw 20:17, 20 June 2008 (UTC)[reply]
Sorry, I'm on XP and I'm using 2.0.0.14. After getting new messages, I can have the flagged messages moved to trash using the Tools menu; I'd like a way to not see them at all. Matt Deres (talk) 23:02, 20 June 2008 (UTC)[reply]
  1. Tools > Account Settings
  2. your account > Junk Settings
  3. Move junk messages to:
  4. select your preferred place (Junk, Trash, Important)
--grawity 19:20, 21 June 2008 (UTC)[reply]
Cool - thanks! To be honest, though, it didn't work until I did the same thing to the "Junk Settings" under Local Folders as well. Matt Deres (talk) 01:48, 22 June 2008 (UTC)[reply]

IP address

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How can one find out their actual IP address? Also, what does it give you when you go to command prompt and type "ipconfig /all"? This is different than the real address. What is it? Also, how does one find their actual IP address? Thanks, Ζρς ι'β' ¡hábleme! 20:37, 20 June 2008 (UTC)[reply]

You can get it at www.whatismyip.com. The IP in ipconfig /all is probably in the 192.168.x.x range; that's a local use range. If it's not showing your true IP address it's almost certainly because you have a DSL modem and/or router between your computer and the wall. If you have just a DSL modem, for example, the modem is making the connection, so it's generating your outgoing IP. Your computer's IP is only used by the modem to connect the two. FYI, if that is the case, you'll see a local address for the modem as well, under "default gateway". If you drop that IP into a browser, you'll get a configuration screen. JeremyMcCracken (talk) (contribs) 21:49, 20 June 2008 (UTC)[reply]
Ah, that makes since. Well, I knew one could get their IP from a website, but is there any way to get it from command prompt? Ζρς ι'β' ¡hábleme! 22:13, 20 June 2008 (UTC)[reply]

There sure is. Enter "ipconfig" without the quotations and hit enter. Acceptable (talk) 22:41, 20 June 2008 (UTC)[reply]

No, when I do that it gives me a "local ID"(?) (ie 192.168.x.x), not my true IP address. Ζρς ι'β' ¡hábleme! 22:53, 20 June 2008 (UTC)[reply]
[3] also works :) --Russoc4 (talk) 00:00, 21 June 2008 (UTC)[reply]
The internet IP address you are looking for is only known by your modem or router, and isn't available to your computer's command prompt. However, you can usually find the internet IP address on the status page of your modem or router as follows. From the ipconfig information, write down the address listed as the default gateway. Then, type that address into your web browser. You should be able to find a status page that will show the IP address your modem or router is getting from the internet. --Bavi H (talk) 01:30, 21 June 2008 (UTC)[reply]
Right. I have SBC-Yahoo with a Motorola DSL modem; if I go to its default gateway address my IP is on the first page. JeremyMcCracken (talk) (contribs) 03:52, 21 June 2008 (UTC)[reply]
Alright, got it. Thank you all, Ζρς ι'β' ¡hábleme! 20:20, 21 June 2008 (UTC)[reply]

Unhide ~/.wine

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How do I make the folder ~/.wine display in browse dialogs and Konqueror as though it didn't start with a dot? I'm using KDE 4. NeonMerlin 22:45, 20 June 2008 (UTC)[reply]

Dot-files were meant to be hidden. If you want one of them, and only one, it is easier to just symlink it to a name without dot, so that it appears among your regular files.
$ ln -s .wine wine
--Juliano (T) 23:05, 20 June 2008 (UTC)[reply]
Pardon me for butting in, but why bother symlinking in this specific case -- why not just hardlink? --Danh, 70.59.79.230 (talk) 23:26, 20 June 2008 (UTC)[reply]
If you can create additional hard links to a directory, you can create some really crazy structures, for example:
mkdir a
mkdir b
ln a b/x
ln b a/y
Now 'b/x' is equivalent to 'a' and 'a/y' is equivalent to 'b', so 'b/x/y' is equivalent to 'b'. In other words 'b' has become a subdirectory of itself - a filesystem loop. To avoid messy scenarios like that, hard linking of directories is not usually allowed. You may be able to do it if you're root, but even then it's not recommended. --tcsetattr (talk / contribs) 00:37, 21 June 2008 (UTC)[reply]
With most filesystems, not even root can make a hardlink to a directory: the filesystem simply doesn't support it -- for exactly the reasons you indicated. MacOSX seems to have implemented it for their Time Machine backup system, but I don't know what they're doing to prevent filesystem loops. --67.185.172.158 (talk) 01:36, 22 June 2008 (UTC)[reply]
Like the anonymous above said, not even root can make hardlinks of directories. That was possible long, long ago, but that "feature" was removed from Linux, because it was only an official and supported way to corrupt your filesystem with 100% accuracy.
tcsetattr explained really well the mess you can do with directory hardlinks. There is another critical point to remember: Every directory links to its parent through a special .. entry. If a single directory is hardlinked from two different places, which one is the parent?
It is possible to have an effect similar of a directory hardlink by creating a bind mount. It solves the problem of the parent directory and recursive directory by making it like a separate mounted filesystem, so the root directory inside the mount have a different .. than the original directory, and it is not recursive.
mount --bind origdir newdir
But this is not persistent, it is a logical (not physical) link, created at the VFS level. Unless you configure it to recreate at boot time, it will disappear as soon as you shutdown your system.
--Juliano (T) 17:37, 22 June 2008 (UTC)[reply]
In the ancient version of Konqueror that I have access to, you can click "View" => "Show Hidden Files". --Sean 15:07, 23 June 2008 (UTC)[reply]