What is a simplest "Crash an application" demonstration to get access to a system?

Question: For a presentation (10-15 mins) purpose what is the simplest demonstration of "crashing an application" on a machine can be done.
Answer: Typically buffer overflows are good - it is generally easier to make one give a crash result than a useful compromise result.
And in general looking at the security advisories lists will be your best bet for current exploits that will crash a server, app or platform.
Answer: The classic document on buffer overflows is Smashing The Stack For Fun And Profit. The examples require a Unix based system, e. g. Linux.
The main example is based on a vulnerable program which is flagged to be executed with super user permissions. Then a second program exploits the vulnerability and ends up with a shell that has super user permissions.
Answer: If you just need to perform a buffer overflow and demonstrate how you would hypothetically take control of the EID to inject shellcode, then you could just write a small C application that just reads in a single command-line argument, and then does a copy() function to move the value into another variable. Then run that command with a huge input string with a debugger (such as GDB in *INX) and you can see it crash and get the memory and register information.


Dataset of number of car accidents per cause in the United States

Question: I am looking for a dataset that lists the number of car accidents broken down by causes in the United States. By cause I mean the direct cause of the accident such as failure to stop at red light, or changing lane without checking for the blind spot. (not the indirect cause such a driving under the influence). Ideally, broken down by year as well.

The Wikipedia page on Epidemiology of motor vehicle collisions contains a list by type of crashes (not cause):

Crashes are categorized by what is struck and the direction of impact,
  or impacts. These are some common crash types, based on the total
  number that occurred in the U.S.A. in 2005, the percentage of total
  crashes, and the percentage of fatal crashes:

Rear impacts (1,824,000 crashes, 29.6% of all US crashes, 5.4% of US fatal crashes)
Angle or side impacts (1,779,000 crashes, 28.9% of all US crashes, 20.7% of US fatal crashes)
Run-off-road collisions (992,000 crashes, 16.1% of US crashes, 31.7% of US fatal crashes)
Collisions with animals (275,000 crashes, 4.5% of US crashes, 0.4% of fatal crashes)
Rollovers (141,000 crashes, 2.3% of all US crashes, 10.9% of US fatal crashes)
Head-on collision (123,000 crashes, only 2.0% of all US crashes, but 10.1% of US fatal crashes)
Collisions with pedestrians and bicyclists (114,000 crashes, only 1.8% of US crashes, but 13.5% of US fatal crashes)
Back-up collisions killed 221 people in the US in 2007, and injured about 14,400. This is one of the most common types of non-traffic auto
  collision in which road workers and children 15 and younger are
  killed.
Answer: The NHTSA has a survey with reasons for crashes.

Table 1. Driver, Vehicle, and Environment Related Critical Reasons
Table 2. Driver‐Related Critical Reasons
Table 3. Vehicle‐Related Critical Reasons
Table 4. Environment‐Related Critical Reasons

https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812506  (mirror)


Cleaning up after a failed BSD Ports Make Install Attempt?

Question: I am trying to clean up after failed installs from ports of Emacs 21 and Emacs 23 as well as Git. I was trying to install Emacs and Git on an OpenBSD v5.2 install on a DEC VaxStation 4000 model 90. It has a staggering 32 megs of RAM and a 2.1 gig hard drive, very high end for 1991 but all this now seems puny; so yes every last megabyte of hard drive space does matter on this hard drive which is now already 72% full.
My attempts at the installs using make install within the appropriate directory of the /usr/ports tree have failed. I did run make clean after each failed compilation and have also checked /tmp and it is largely empty. OpenBSD seems to also flush /tmp with each reboot. The hard drive capacity does however seem to shrink with each failed program compilation so I am probably accumulating some programs or tarballs or cruft with each attempted installation.
The programs in question are not available as binary packages for the VAX architecture.
How do I clean up after failed ports compilations in this scenario?
Answer: Run rm -rf /usr/ports/pobj.
Check also the directory packages within /usr/ports.


Natural remedies to get rid of flies (Housefly)

Question: I'm really got fed up with these irritating buzzing flies all over my house. What is a natural way to repel or otherwise get rid of the flies?
Comment: Place well readable signs all around your house saying `Here Be Frogs`.
Comment: Start by putting fly nets on all windows and doors which are usually open. We live in an agricultural area and this is what keeps us sane.
Answer: I don't know if most people knew about this remedy to avoid houseflies already.
Using plastic water bags to keep away flies.
My friend has a grocery store and I have seen him hanging half filled plastic water bags on the entrance of the store. I didn't know the reason behind this until now but after searching about it I got this.

There are at least two reasons explained for this remedy which seems to be beyond logic. One is that the flies are not able to see the water bag as a water bag. Due to their structure of eyes, clear water filled bags are seen as something resembling a spider's web by the flies. As such, they don't come near such a thing. The other reason states that the reflection of water is enough to disorient the flies and to create some inexplicable illusion to them.
Get this:
Clear plastic bag (gallon size)-1
Water
Do this:
Fill the plastic bag with water. Keep it halfway full with water.
Tie a knot at the mouth of the bag to secure it properly. You may also use a thread or a rubber band for the purpose.
Now just hang this water filled plastic bags near your entryways, garage doors or any other such outdoor entrance.
Advantages:

doesn't harm any housefly; only keeps them away.
doesn't use any harmful chemical.
cheap

Source: Google
Comment: I saw it used against cats and against pigeons. It sure doesn't work against pigeons, don't know about cats, I bet it doesn't work against them, either. I want to try it against houseflies to see how it doesn't work against them, too. Sadly, I have no houseflies :(
Comment: Me too. Thanks for this lifehacks; in (& around) our family cottage on the mountain there is a lot of flies.
Answer: I have myself gone through the same problem last year. So, as per my personal experiences, I will suggest you few methods:

Using Carnivorous Plants: Adding a few carnivorous plants such as Venus Fly Trap or pitcher plant near the infested area can also help in controlling the fly infestation. They are slow but they work.

Using Lavender Oil Repellents: Lavender helps to control the infestation of flies along with repelling fleas, black fly, black beetle, greenfly and whitefly too. To make the repellent:

Dip a cloth or a sponge in the lavender oil.
Next, place this cloth or sponge in the tin can, put on the lid and leave it for 24 hours.
After 24 hours, remove the lid and keep the tin at a place where you see most of the flies in your home. You will see that flies will be repelled by the lavender fragrance.

Lemongrass Spray: Lemongrass oil is one of few sprays that flies hate the most. You can pour 10 -15 drops of lemongrass oil in a spray bottle. After this put 2 cups of warm water in the spray bottle. Shake the mixture well and spray over the infested areas.

Herbs that can help you to get rid of flies: Flies hate certain herbs like Basil, Lavender, Bay Leaf, Tansy, Mint, Rue, and Wormwood. If you plant these herbs in the infested area you will see that flies leave the area quickly.

Camphor to Repel Flies: Camphor has a strong smell that deters flies and other insects. It has been traditionally used in India to purify the surrounding environment as it has strong antibacterial, anti-viral, and insect repellent properties. It is commercially available in form of small tablets. Take 2 camphor tablets and place it on a warm surface near the infested areas. This works like a charm.

A fun way to kill flies: Bug-A-Salt looks pretty much like an "assault rifle", the rifle uses regular table salt to shoot a concentrated spray pattern of salt granules (very much like a shotgun), killing the flies and other flying insects on contact.
The salt used in the gun would not damage your walls or furniture but it is strong enough to easily kill flies. This fly rifle is a non-toxic, battery-free device that allows you to have fun while getting rid of flies.

There are many such other methods mentioned on www.fliesonly.com.
Hope this helps.
Answer: I saw a good one where you take a water bottle and cut it in half.  Then take the top half, invert it, and place it into the bottom half.  Place a small amount of beer/juice/etc. in the bottom.  The flies will go in and will often not be able to escape.
Comment: Our flies wouldn't be too interested in that bait. Wasps otoh and fruit flies would.
Comment: I'll try it. Maybe is good to coat bottle (with some nice decorative paper), to avoid view on flies. :)
Answer: Putting some of the plants and materials flies hate around a home tends to work. They cannot strong-smelling plants like basil and lavender, but essential oils like Eucalyptus and Lavender also work great. Orange peels also contain the citrus flies hat and can be used to the same effect along with any camphor you have.
Answer: Get a strip of paper and coat it with a sticky substance (glue/resin) that does not dry out for a dew days. Hang a couple of these sticky strips from your ceiling with thumbtacks and some string.
Flies will randomly land on them, get permanently stuck and perish. After a few days, take down the strips and throw them away. In my country you can just buy these strips rolled up in little canisters, coated with some extremely sticky resin.
They are completely non-toxic, so as far as I am concerned this is a "natural" solution.


Thought arising

Question: I often hear it being said that with meditation/mindfulness we observe the thoughts and feelings coming and going but I'm not sure if this is a clear explanation of what occurs because in my experience of practicing for over 6 years I don't think I have ever actually seen a thought arising. What happens with me is that I recognise that my mind is lost in a thought and once I do then the thought ends. This is different to noticing the arising. So I'm following breath, lost in thought, come back to breath, lost in thought etc. I can intentionally say to myself "ok now I'm going to think about ...." And in this way I can observe the process of thinking but unless I do this I don't see how its possible to see a random thought arising. Is this correct?   If this is not correct then why in 6 years can I still not do this?  The recognition of random thought is always in past tense.
Comment: It takes most people longer than 6 years, but keep at it, you will experience it eventually. Didn't the Buddha say it takes at least 7 years?
Answer: The presence of random thoughts make meditation impersonal, i.e., non / not self. You can realise you have no absolute control over thoughts. The nature of your flickering mind can also help you understand the 3 Characteristics.
When thoughts or other distractions arise (like pain), observe the sensation.

The meeting of the three is contact.
With contact as condition, there is feeling.
What one feels, one perceives.
What one perceives, one thinks about.
What one thinks about, one mentally proliferates.

Madhu,piṇḍika Sutta
Most proximate cause for thoughts to arise is perception. But what decides whether it is unwholesome or wholesome is feelings. So see thoughts arise be mindful of feeling and perception. Knowing these only will help you know what you are about to think about. Feelings will decide the wholesome / unwholesome root and perception will refine it with past experiences, memories, mental model to your intended action. Thinking about or thinking and pondering will lead to planning out the action in more detail.
Also:

(1) the latent tendency to lust reinforced by being attached to pleasant feelings;
(2) the latent tendency to aversion reinforced by rejecting painful feelings;
(3) the latent tendency to ignorance reinforced by ignoring neutral feelings.

Thinking lead to volitional activity and mental fool (Ahara). Also from feeling, Kamma arises:

... one generates that  formation, conditioned by which pleasure and pain arise internally

(Kamma,vāda) Bhumija Sutta
So once feeling arises you should try to stop this process leading to arising of the unwholesome roots, providing nutriment, arising of Kamma, leading to mental proliferation by being equanimous and noting impermanence. There are 2 paces which you can attack Dependent Origination, that is at ignorance and feeling. Knowing impermanence displaces ignorance and being equanimous stops feeling proliferating to craving and clinging.
If you were unable to stop when the feeling due to contact arises, when the volitional tough arises the respective feeling also arise in the body. This is a place where you can contemplate about moral constraint (Sila). Taking a step further you can constrain your thinking also, by contemplating the sensation it created and being equanimous towards it while seeing its impermanence, and perhaps neutralising one's perception by developing the opposite perception. [Indriya Bhāvanā Sutta] This you can use as a tool to prevent bad kamma (in account of feelings you should lessen unwholesome states and increase wholesome states - Kīta,giri Sutta):

Ananda, with ignorance as condition:
when there is the body, because of bodily volition, pleasure and pain arise internally;
when there is speech, because of verbal volition, pleasure and pain arise internally;
when there is the mind, because of mental volition, pleasure and pain arise internally.

(Kamma,vāda) Bhumija Sutta

Agitation and peace cannot co-exist. One way to achieve inner peace is Vipassana or insight meditation - a non-sectarian, scientific, results-oriented technique of self-observation and truth realization. Practice of this technique brings experiential understanding of how mind and body interact. Everytime negativity arises in the mind, such as hatred, it triggers unpleasant sensations within the body. Every time the mind generates selfless love, compassion and good will, the entire body is flooded with pleasant sensations. Practice of Vipassana also reveals that mental action precedes every physical and vocal action, determining whether that action will be wholesome or unwholesome. Mind matters most.

S N Goenka addresses UN Peace Summit
So when thoughts arise see that sensation is associated with it, knowing its impermanence thus ensuring it does not proliferate to unwholesome actions or further unwholesome thinking. Once you have realized the distracting thoughts, know the sensation associated with it and seeing its impermanence, finally return to the object of your meditation. In case it is breath meditation then return to the breaths. This is the most effective way to let go of distracting thoughts.
Also see: Sal,āyatana Vibhanga Sutta
Answer:
I often hear it being said that with meditation/mindfulness we observe the thoughts and feelings coming and going but I'm not sure if
  this is a clear explanation of what occurs because in my experience of
  practicing for over 6 years I don't think I have ever actually seen a
  thought arising.

Yes. To clearly see a thought arising is a very advanced practise because it can really only occur clearly when the mind is strongly established in an empty concentrated mind.

What happens with me is that I recognise that my mind is lost in a thought and once I do then the thought ends.

Yes. This is a very honest & accurate appraisal of your practise.

Is this correct?

Yes. What you posted (in detail) is correct.
When the Buddha listed dhammas in various teachings, he generally did so from less advanced to most advanced. In AN 4.41, the Buddha listed 'knowing thoughts as they arise' after the practise of jhana. Whilst jhana is not necessarily a pre-requisite in all cases, to be perfect at 'knowing all thoughts as they arise' would require the development of jhana.
It is also important to understand that what is called 'cittanupassana' or 'contemplation of mind' is not related to thoughts and occurs when the mind has concentration (such as described in the Anapanasati Sutta, where 'contemplation of mind' is practised together with knowing each in-breath & each out-breath).
In other words, most Buddhists are fooling themselves when they believe they are successfully practising observing the mind. In your case, as I mentioned, your appraisal of your practise is not only honest but also accurate, in that you have the awareness to know you catch the thought after it has arisen rather than as it is arising.
Answer: What is a thought? In a Buddhist context thoughts (Citta) and thinking(Cétasika) are not the same.
(in context of thought as a noun, thought as in having thought and thinking thoughts)
Since it is important to proceed with knowing the difference, I will give an example I've learnt to clarify this. When you get angry, you can decide not to be angry and calm yourself down. Once the thought of anger came to you(Citta), if there was no way to act, i.e think (Cétasika) you won't be able to stop your anger
Next, citta and cétasika arise bound to one another, stay bound to one another and perish bound to one another. They occur only sequentially and in countless numbers per eye blink.
Comment: @Dhammadhatu may I know where it is obvious that I do not practice this? The answer attempts to show that observing thoughts (Citta - Vinñana) has to be done using (Cétasika - Védana, Sangna, Sankhara). These subtle differences can be seen in "some" thoughts as you practice Sathara Sathipattanaya. A person who knows the theory also knows why it is hard to bind each thought to an observant cétasika "easily". May you realize the Four Noble Truths...
Comment: This ("they occur only sequentially and in countless numbers per eye blink") sounds like theory rather than practise. You personally obviously do not practise this but have only read this in a book. It follows it is not an answer to the question. Regards

Thought arising


Why isn't Google crawling on my blog?

Question: I have a blog. I made it in August, 2010. It has been awhile, but I am unable to make Google crawl on my site. I have requested Google to crawl but there is still no response. Are there any reasons of note why it is happening?
Comment: I've just now found Google's cache of your page on 16 Nov 2011. Don't say this!
Answer: You don't to request that Googlebot visits your blog.  You don't need to worry.
First of all, you just write as many articles as you can (but with good quality.)
Advertise them among your friends then on social networking sites.
Once your site start getting traffic, you'll automatically be included in search results.
Moreover, register your site with Google Analytics and Google Webmaster Tools. Those will show statistics about the actual activity of the Googlebot crawler.
Comment: I tried pinging google with my blog name and it worked
Answer: If you want fast and guaranteed crawling, create a google adsense account and ad the google ad to the source code of your site.  You can do this just until they spider the site, and you can probably do it on pages that simply link to your important content, and which only spiders are otherwise going to be likely to find.  Since they advertise based on content, they'll have to spider your site, discover it's existence, index it, and presumably index all of the pages that you actually -want- it to see as well.
Then remove the ads whenever you're ready.
Comment: How does adding advertisement help?Some days back I tried putting google adds on my site but they replied back that the site was not of good quality : /
Comment: AdSense spider and Search spider are different.
Answer: I see it's a blogspot blog so I'll skip most of the common reasons that googlebot might not visit.
Did you get any inbound links? Put your blog on some free directories and social networks and see what will happen.
Comment: I have 13 backlinks so far,still no crawling
Comment: Try adding some more. I looked through it and failed to see any other reasons.
Comment: don't see how this answers the question. Using backlinks can make the indexing / crawling faster but to be honest theres most more constructive things you can be doing with social media and building even more content the time it takes to worry about crawling times.

Why isn't Google crawling on my blog?


Unable to add printer

Question: I am unable to add a printer as the 'Add' button is greyed out. Its an HP Deskjet 3520 - I'd like to connect to it wirelessly.
Comment: First thing to do after installing Elementary OS check if can install your printer. If not - Install Kubuntu.
Comment: No seriously, if printer install does not work from the normal printer settings - open the web browser and paste in 'http://localhost:631' in the adress field and then use your elementary user and password to install the printer from within the CUPS browser interface.
Comment: If you don't have CUPS on your computer use 'sudo apt-get install cups' in a terminal window.
Answer: The Connection field should contain the protocol and the local address of the printer, something like socket://hostname or http://hostname:631/ipp/.
There are several ways to try:

Use sudo hp-setup -i in Terminal and follow the instructions
Go to CUPS and add the printer from here
Find your printer's local IP or (preferably) assign a static IP (either using your router's configuration or the printer's menu) and use that in the Connection field
sudo apt-get install hplip-gui && hplip-gui and follow the instructions (also installs a lot of dependencies and requires a temporary USB connection to the printer)
Comment: What worked was adding socket://
Comment: Glad it worked. Now, it is worth mentioning that using hplip-gui should also add scanning functionalities.
Answer: To add to above since I can't comment yet... You also have to fill out the description before the 'Add' button enables. It will have example text, but I thought it would just use that, so I kept trying different things and it wasted my time for no good reason.
At the time of this writing, the minimum to trigger the 'Add' button (assuming http) is 'http://' in connection with one character in 'Description'.
I love EOS and the setup was still far easier than I've dealt with in the past, so not complaining, but to the devs - I feel like intuitiveness was overlooked a bit here. When I just see a grey 'http' and nothing else, I wonder, "well, should I just enter an IP? If not, should I have a terminating /? Does it expect the port or can I just use the ip if the protocol is specified at the beginning?" When I was trying 'ipp' it was the same; I was like, "well do I need to do ipp://(ip)? or (ip address)/ipp?" or "ipp://(ip address)/ipp?" - My point is, it definitely should not just be 'http' or 'ipp' and nothing else showing there. It should look near exactly what is expected for the end user.
Answer: I'm new to Linux so when I finally got EOS installed I was pumped. I love the look and feel of MacOSx b/c I use but dislike Windows. And I was hoping this would work b/c I am trying to move whole house to Linux.
I ended up installing another Linux distro over EOS unfortunately because of the lack of intuitiveness and ease of installing not just the printer but a couple other apps.

Unable to add printer


Can an enameled dutch oven be used for stir frying?

Question: I want to use a KitchenAid enameled cast iron dutch oven for stir frying Asian style. Are there any issues with using it for stir frying? I am a cooking newbie, and want to find healthy cooking options for others in my family who cook.
Answer: I wouldn't do it, for a few reasons :

Cooking over extreme heat can damage the finish of enameled cast iron.  It will typically cause discoloration if you have a white interior, and it may cause crazing (fine lines all over the place).  It can also soften the enamel enough to fuse he pan to the stove.
The high sides of a dutch oven hold in steam, which will change how the food cooks.
It's more difficult to keep things moving in a large pot to ensure even cooking when cooking over high heat.

You would be better off just using a skillet, and working in batches and re-combine everything when done.
Answer: Do not use an enameled Dutch Oven for stir-fry. But you can do it with a non-enameled heavy cast-iron one.
The secret to guaranteed great kitchen stovetop stir-fry is essentially to heat a heavy-duty cast-iron Dutch oven as hot as possible. Specifically:

I have a well-seasoned Lodge, heavy-duty, 7-quart, cast-iron Dutch oven. It is an indoor-kitchen model without the legs or loop-handle the outdoor models have. It's not enameled, just black iron. But it's very heavy-duty, and that is the secret.
I use a laser thermometer gun to keep track of temperature/timing.
I put the clean, empty Dutch oven on a burner and turn the burner on all the way. Then, I wait at least 25 minutes as the iron heats up. Yes, 25 minutes (or even a bit longer), with nothing in the pot. Use a timer for best results. It takes this long to build up to its highest possible temperature (about 760F in the middle). The hotter the better.
When I prepare something to be stir-fried this way, I add the oil & flavorings (soy sauce, fish sauce, oyster sauce, sriracha sauce, etc---Whatever particular combo of flavorings the dish requires) on top of the stuff (cut veggies or meat) in a large bowl, along with a sesame oil/peanut oil combo, again, poured on top.
When I'm ready to stir-fry, I pour all the ingredients to be fried, plus oil and sauce in together, simultaneously. No need to stir in the bowl, they'll be mixed when you stir in the pot. Not putting the oil in ahead-of-time avoids unnecessary (and dangerous) spattering.
Stir with a long-handled spoon or other long utensil. It is smart to wear oven-gloves if you are afraid of burning yourself. It's super hot. Be careful and alert around it, and you should have no problems.
Stir-fry meat separately from most veggies, for best results (if you do the meat first, as I do, you can pour it, still-warm, in with the veggies right at the end (as veggies finish), frying them all together very briefly, before putting the finished dish in a serving bowl.
After cooking, while the Dutch oven is still hot, I pour in a couple cups of water to cover the bottom keep the cooking residue hydrated for easier cleaning later on.

The long pre-heat period gets the Dutch Oven to a temp that is hot enough to truly fry the food, and not just steam-boil it, as is the case with regular frypans and thinner woks when used over a regular stovetop burner. Try it -- it is a revelation. The flavor is identical to a professional Mongolian stir-fry or Chinese restaurant.
But do not use an enameled Dutch oven, only a heavy cast-iron one.
Comment: Done. See below. Hope that helps.
Comment: Thanks for coming back to edit your answer. To actually answer the question, would you say that, no, you should not use an enameled dutch oven for stir frying? This is a nice explanation of how to use a cast iron dutch oven but if you could explain why an enameled one should not be used, that would more directly address the concerns in the question. :D
Answer: I don't think there is anything wrong with using a dutch oven for stir fry, but the warnings about using enamel in high heat is something you should take note of. Enamel Dutch Ovens are the predecessors of slow cookers and should generally be used as such.
Lodge has a 14 inch cast iron wok which is one of my favorite cooking tools, especially for stir fry. They also have non enameled dutch ovens if you are looking for a multi-purpose tool. Make sure you get one big enough for the size of your family. My 5 qt dutch oven barely makes enough food for 5. I never have enough stew even when the liquid level is brought to within a 1/2 inch of the top. I haven't yet, but I need to add a 7 qt oven to my arsenal.


Extract part of an image in Google Slides

Question: In a Google Slides presentation, is it possible to extract part of an inserted image and use it as a new image?
Answer: Google Docs Presentation only has a very limited set of image options ranging only to resizing, rotating, and moving.  Any additional image manipulation must be done with other software.  Many options are available in this area, from free to big dollars, such as Paint.NET and GIMP up to major programs such as Photoshop.  Each of these editors have their own advantages and disadvantages depending on what exactly you need to do.  If you only need to do basic cropping then you can use Paint on Windows or Paintbrush on Mac which both come free with your OS.
Answer: For a quick and easy solution, you could use a screenshot program such as the Snipping Tool in Windows or Screenshot in Ubuntu/Linux to crop whichever part of the image you'd like to select. Most screenshot programs have the option of selecting just a section of the screen. You'll have to save the cropped image as a new image and manually re-insert it into the Google Docs presentation.


What is required to house break a rabbit?

Question: I have heard that rabbits make good pets.  How hard is it house break rabbits?
Answer: Rabbits are very clean and easy to train for litter tray use. In nature, rabbits spend a lot of time in hutches and warrens, so learning to use a corner rather than where ever they are keeps their living area clean. This means your job as a rabbit owner is much easier as evolution has done most of the hard work. Most...
Finding their "spot"
When first house training your rabbit, confine them to a small section of the house, preferable one that is easy to clean such as an area with non-absorbant flooring, like tiles or linoleum - as with all animals, rabbits will make mistakes at first. In this confined area, in the corners you want to play several small litter trays over newspaper to catch any spills. As suggested, if you can, place something that has been soiled into the trays to reinforce the smell - however be careful with which wood you use, why is discussed below in the section on litter.
Over time you will notice that your bunny will prefer one spot over another. As they start this preference, slowly remove the other trays one at a time. If they do have accidents in other spots, return the trays and start again. But its very likely your bunny will pick up on whats happening.
Once they have a spot chosen, you can get a larger (more elborate) tray, and eventually they will imprint on the litter tray, rather than the area. This allows you to move the litter tray to a more convenient location, or if you need to leave your bunny with someone else the litter tray can go with to reduce mess.
Choosing the right litter
Rabbits are not cats and some litters designed for cats are not appropriate for rabbits. Above all else, softwood litters such as those based on pine or cedar must be avoided!. Safer choices include paper or hardwoods. Take time to find the right amount of litter for your rabbit, as they all have different preferences.
Dealing with mess
Number one: loose litter
Rabbits have larger and stronger legs than a cat, and a stronger urge to dig. This means that litter, especially used litter, can go flying. The best thing to minimise mess is to get a larger, deeper litter tray. Rabbits will often try to position themselves in a corner when relieving themselves, so positioning the opening in a way away from their chosen corner of the box will help reduce spillage. The below image shows an ideal rabbit litter tray:

Do not enclose the litter tray unlike in in nature, your bunnies litter tray is not a porous earthen enclosure with plants that enthusiastically absorb nitrogen. It is non-porous tray that needs to be emptied frequently and if left enclosed will allow nitrogen to build up. Rabbit pee can smell, so more often cleaning, or more absorbent litter is the answer. Enclosing the trya will just enclose the smell, and your rabbits nose is much more sensitive than yours, if the smell builds up too much they will just not go there, and will choose another place to go - like your bed.
Number two: "happy trails"
Rabbits occasionally suffer from excitement induced fecal incontinence, or cutely known as "happy trails". When excited, whether during positive experiences such you coming home, during feeding time, or new vistors, or negative experiences, such as for some rabbits, nail clippings, your bunny may release dropping pellets. This is outside of their control, and they will usally be very hard and dry, and easy to clean up. This is one of the joys of owning a rabbit.
Pampering your rabbit
Rabbits are more comfortable in an area when they can eat. So add some hay to their litter box. This also helps to passively position the rabbit into a corner, as rabbits are quite clean and won't relieve themselves on their food. So by positioning the hay in one corner of the box, you encourage the rabbit to go in the opposite one.
Waste not want not
One a final (slightly off topic) note, as mentioned rabbit waste from a well fed bunny is very high in nitrogen. If you use a recycled paper based litter, the used litter is excellent fertilizer and can be used in the garden, for example to grow nice leafy green vegetables, to feed to your rabbit... thus completing the circle of life.
Comment: May I add two points to your answer?  1. Poops dropped in new territory.  2.  When the bunny wants the litter box someplace else.
Answer: In my experience rabbits are very easy to housebreak. They like to pee and poop in the same place every time, so in most cases all you have to do is put a little bit of their waste in the litter box and they will happily use the litter box. It is very important that if they go somewhere else, miss the edge or kick waste out of the box that you clean it up well and immediately as otherwise those spots will become existing places to pee and poop. When you clean the box, save a little bit of waste and put it in the cleaned box so it smells right to them.
For a more foolproof method, you can get a piece of wood soaked with their urine and put that in the box along with droppings or cage them so that they are only in their litter box for a week.  Generally, if I try the first method and find that they are not using only the box on the first day, I go for the litter box only for a week method. The wood block works well if you are moving from a hutch outdoors to a litter box indoors. If you have an indoor cage, you can use the cage itself as the litter box (or attach a litter box to the section of the cage the rabbit has used for waste.)
Be sure to use clay or newsprint litter as the other types aren't necessarily good for rabbits. Wood litter is okay if you are sure it isn't fir. The most important thing is to clean anywhere they have an accident. High sided boxes help with avoiding kicking soiled litter out of the box, which is the biggest cause of failure in my experience.
Answer:
...rabbits can be easily trained to use a litter tray, sometimes with more reliability than your average cat!
The natural instinct of a wild rabbit to use one area as its latrine is still apparent in its domestic counterparts.  (1)

The actual process is very similar to pad training a dog or litter box training a cat. Keep the rabbit confined to a small area while training, move any "accidents" to the litter box, and the rabbit will naturally start using that area for its business. The source link has the details.

(1) Litter Training Your Rabbit
Emma Magnus MSc
Association of Pet Behaviour Counsellors
apbc.org.uk
Comment: We prefer that answers here be self contained.  Perhaps you could quote the relevant sections from the link here.  This will also help prevent loss of information in the event of link rot.
Answer: I just got my first bunny on "Black Friday" and appropriately named her..."Friday".  She's a 7 1/2 week old Lion-Head mix (Not sure what the other breed she's mixed with).  I'm not sure about others, but she's remarkably calm when handled, not skittish in the least bit, and seems to have no problem with new people.  Within hours I had her hopping, under my watchful eye, around my bedroom (with the door shut).  She did drop lots of "happy trails" at first...LOTS.  Then she peed in the corner, I quickly returned her to her cage.  Later, she would pee in 2 other places before I decided to read this article!  Lol.  Here's what I did:  Starting off with a confined area does make litter training more "do-able" for the bunny.  I actually made a make-shift litter box out of a coffee-maker box.  I reinforced it with tape (inside and out)covering all the corners/edges and interior floor of the box with tape as a means to seal the box from "pee-pee" leaks.  I then put some fresh litter in - then the IMPORTANT part - I put a little SOILED litter and FRESH "bunny poops" right in the back CORNER of the litter box.  I also placed some fresh greens in the OPPOSITE corner.  I opened her cage, directed her to the litter box - she jumped right in, turned around, did her business in the corner where I placed the soiled litter while happily nibbling away at the greens which faced her from the opposite corner.  I praised her with lots of petting and "Good Girl!"s.  To reinforce this positive experience, I let her hop around only for another minute or two before returning her to her cage for the night to avoid any more accidents.  We will repeat in the morning.  First attempt, successful!  Good luck!  -Taron & "Friday"


Override taxonomy term display page with panel page

Question:
I am having a menu built using taxonomy terms which links to a URL pattern like shop/[Term name] this is a dropdown menu.
I have created a panel page which takes an argument in the URL i.e (shop/!argument).
In the panel I have added a contextual filtered(has Taxonomy term) view and checked "send arguments" option in settings.
so obviously the taxonomy term display page is where I land when clicking the links.
I don't want to use the taxonomy term panel or the views page for taxonomy which comes with drupal core itself.
I want my panel page to override the taxonomy term display page
this is only for two types of vocabulary terms, any ideas how?
Answer: Have you tried this tutorial? http://drupaleasy.com/blogs/ultimike/2010/10/taxonomy-term-pages-steroids-using-panels-views


How to search sequence of API call using IDA Pro?

Question: I want to search the sequence of API call using IDA Pro. How to search the API call node execution and what is the next API call node execution followed using IDA Pro.
Comment: I don't think it is possible, other than searching for the first call and then browsing the results to check for the second call. Or write a a script to do this.
Answer: I would take a look at https://github.com/deresz/funcap. It might not have all the sequencing information you're looking for but I used it as a basis to do something similar a while ago.
If you don't want to do it dynamically with IDA's debugger, you can similarly use an IDA Python script to parse the callgraph of a binary. I think Grey Hat Python has a section on IDA Python if you don't want to/can't find open source resources (though I believe there are other plugins that do something like this).


How can I quit ediff immediately without having to type 'y'

Question: When I quit ediff with q I get asked if I really want to quit. I'd rather it quit immediately. There is nothing obvious under customization. There is a solution here which seems to work by redefining the q key, but I'm not sure of the details of how the function works. What's the simplest way to get quit to really mean quit?
Answer: You can advise ediff-quit so it dynamically rebinds y-or-n-p to a function that returns t.
(defun disable-y-or-n-p (orig-fun &rest args)
  (cl-letf (((symbol-function 'y-or-n-p) (lambda (prompt) t)))
    (apply orig-fun args)))

(advice-add 'ediff-quit :around #'disable-y-or-n-p)

This is more robust to upstream changes than redefining ediff-quit.
Comment: If it would notify that if any differed buffer changed, it would be perfect.
Answer: Unfortunately I think you do have to either rebind q or adjust the source of ediff-quit. As is apparent in the source of ediff-quit the prompt always happens.
(defun ediff-quit (reverse-default-keep-variants)
  "Finish an Ediff session and exit Ediff.
Unselects the selected difference, if any, restores the read-only and modified
flags of the compared file buffers, kills Ediff buffers for this session
\(but not buffers A, B, C\).

If `ediff-keep-variants' is nil, the user will be asked whether the buffers
containing the variants should be removed \(if they haven't been modified\).
If it is t, they will be preserved unconditionally.  A prefix argument,
temporarily reverses the meaning of this variable."
  (interactive "P")
  (ediff-barf-if-not-control-buffer)
  (let ((ctl-buf (current-buffer))
    (ctl-frm (selected-frame))
    (minibuffer-auto-raise t))
    (if (y-or-n-p (format "Quit this Ediff session%s? "
              (if (ediff-buffer-live-p ediff-meta-buffer)
                  " & show containing session group" "")))
    (progn
      (message "")
      (set-buffer ctl-buf)
      (ediff-really-quit reverse-default-keep-variants))
      (select-frame ctl-frm)
      (raise-frame ctl-frm)
      (message ""))))

I would suggest redefining ediff-quit in your .emacs and submitting a patch to the source adding a customization variable.
Remember that the implementation source in emacs is always a few keystrokes away. Presuming the elisp sources are installed, type C-h f, enter the function name and follow the link to where it is defined.
Answer: I use the following rebind of q in ediff. If any of the buffers are modified, it asks if they are to be saved, then it just quits. If no buffers are modified, it just quits.
(add-hook 'ediff-startup-hook
          (lambda ()
            (local-set-key (kbd"q") 'my-ediff-quit)))

(defun my-ediff-quit ()
  "If any of the ediff buffers have been modified, ask if changes
should be saved. Then quit ediff normally, without asking for
confirmation"
  (interactive)
  (ediff-barf-if-not-control-buffer)
  (let* ((buf-a ediff-buffer-A)
         (buf-b ediff-buffer-B)
         (buf-c ediff-buffer-C)
         (ctl-buf (current-buffer))
         (modified (remove-if-not 'buffer-modified-p
                                  (list buf-a buf-b buf-c))))
    (let ((save (if modified (yes-or-no-p "Save changes?")nil)))
      (loop for buf in modified do
            (progn
              (set-buffer buf)
              (if save
                  (save-buffer)
                (set-buffer-modified-p nil))))
      (set-buffer ctl-buf)
      (ediff-really-quit nil))))


Sketchup tag rename needed

Question: We have two Sketchup tags: sketch-up and google-sketchup.  They both refer to the same program and neither tag name is correct.
The first has five questions and the tag was created with an incorrect name and no wiki summary.  It might have been intended to refer to sketching applications in general, but that duplicates the [drawing] tag, so it is unnecessary for that purpose.  All five of these questions also have the [google-sketchup] tag, so the [sketch-up] tag is entirely redundant and can be deleted.
The second has 34 questions and a wiki summary.  Sketchup was created by Google, but is now owned by Trimble, so the google part of the tag is incorrect.  The Trimble name is not well known, so replacing google with trimble would be more confusing than useful.  Sketchup is a trademarked name, so no company name is really necessary.
Suggestion: Rename [google-sketchup] to [sketchup].  The wiki summary will also need to be updated.
Answer: Done. sketchup now  has all those questions.
Feel free to provide a short tag wiki.
Comment: Done.  Updated and expanded the existing one.

Sketchup tag rename needed


Importance of Rest Days

Question: Why are rest days important?
When the weather permits, I jog (or otherwise work-out) every day, but people often tell me I should not, because rest days are important. What is the rationale behind this?
Answer: Evidence shows that more than 5 days a week training increases your risk of musculoskeletal injury.
Rest is physically necessary so that the muscles can repair, rebuild and strengthen -- continuous training can actually weaken it. Without sufficient time to repair, the body will continue to breakdown from intensive exercise.
Overtraining often occurs from a lack of recovery time.  Some signs of overtraining are feeling of general malaise, staleness, depression, decreased sports performance and increased risk of injury.
This image from pponline.co.uk explains why you need some rest.

Making sure to workout when you're muscles are slightly stronger than before your workout will allow you to literally built up your muscles:
Comment: Now what is that time at after a bout where strength due to supercompensation is at its peak?
Comment: @에이바-I recently took two months off (competitive swimming) due to overtraining and three months later, I am forced to take yet more time off due to overtraining again. Do you think this is the same bout of overtraining, and that I just didn't recover from it fully the first time? Any help would be very much appreciated!
Comment: Overtraining, depending on the extent, can take weeks to years to recover from. I know of cases that recovered after 2-3 years. So most probably you did not recover from it the first time. Also, once you do recover, and can go back to practicing, there is a phase in which you should be very careful. You might be able to practice, but to get back to where you were before takes many years.
Answer: Without rest, you will build muscle mass quicker than your supporting organs can build and adjust to enable their proper use. At that point, you will hit a plateau which you will be unable to cross. However, this does not hold true for aerobic exercise, where the Mayo Clinic suggests 30 minutes daily. This is more for muscle building and strength training.
Answer: It has everything to do with the person. Top athletes train every day, and a lot of hours. Usually, they have spent some years making the body able to withstand a lot of training.
I was the fastest running youth in Norway some years back in 60-200m, and trained about 20 hours a week in the weeks with the most load. That was when between the age of 15 and 18. I had no problems with injuries, but again, this is often individually.
If someone wants to train everyday, like I do, the trick is to have a lot variation in the training. One simple example, just to easily show what I mean is this:
Monday: Running
Tuesday: Upper body weightlifting
Wednesday: Lower body weightlifting
Thursday: Mobility and stretching
Friday: Running
...
Answer: Supercompensation would be some of the explanation if the goal is to get in better shape.
As I understand it: When the body rests it creates more muscle mass than what was actually destroyed during the exercise.
Answer: I assume this depends on person, as well as speed and duration of the exercise.
Personally, after running few days in a row I get muscles tired: it feels like your legs are filled with lead. Not something you want before a big college competition.
But if you notice no changes in your body, I daresay it's ok. Walking is also an exercise and we do it daily without a problem.

Importance of Rest Days


Donkey Talked and an Angel Appeared - Who Knew?

Question: Why is no mention made of the reaction, of Balak's officers who were accompanying Bilaam, to the talking donkey or the revelation of the angel?
Answer: The Daas Z'keinim and Paneiach Raza write that the angel killed the officers who were traveling with Bilaam, which explains why no further mention is made of them. Rabbeinu Bechaye explains that they were traveling in front of Bilaam and therefore didn't observe or hear the commotion and exchange between Bilaam, his donkey, and the angel. Alternatively, even if they were present, they weren't on the same spiritual level as Bilaam, and they were unable to see or hear anything out of the ordinary. Rav Aharon Leib Shteinman suggests that even though they witnessed and heard the exchange, the officers didn't reflect on the miraculous scene that they had witnessed and it made no impression on them to reconsider the propriety of their plans, so no reaction was mentioned on their part.
From:Parsha Potpourri Points to Ponder
Answer: Perhaps they were astounded, but the pasuk does not mention it, because it is not relevant to the narrative.
Alternatively, perhaps because this was all part of a dream sequence? See Ibn Caspi, or see Dr. Yitzchak Levine.

Where were Balaam's two servants during these discussions and events? Where were Balak's officials and dignitaries? Not in the dream! Only in the morning, when Balaam awakened and actually set out on his way, were they with him. Likewise, as regards the contradictory stance, as it were, of the Almighty (Question 8 above), only if one does not pay close attention to the structure of this description does it seem that G-d, after giving Balaam permission to go, was angry at him again, and then in the end He once again changed His mind and permitted Balaam to set out. But this only seems so if one does not distinguish the general heading (v. 20) from the details of the dream that follow. The inappropriateness of some of the angel's remarks as well, stem from the fact that Balaam was dreaming.
Answer: R' Schwab in Maayan Beis Hasho'eva uses this question to answer two other questions (My summary looks long, but it's really pretty brief).
He is bothered how Chazal knew from the words כי הולך הוא (Bamidbar 22:22) that Bilaam was going out of a desire to curse Israel:

כי הולך הוא" - ראה שהדבר רע בעיני המקום ונתאוה לילך"

And his second question is why Hashem got upset with Bilaam for going, put an angel there to stop him, and then told him to go again!
Bamidbar 22:20

וַיָּבֹא אֱלֹהִים | אֶל בִּלְעָם לַיְלָה וַיֹּאמֶר לוֹ אִם לִקְרֹא לְךָ בָּאוּ הָאֲנָשִׁים קוּם לֵךְ אִתָּם וְאַךְ אֶת הַדָּבָר אֲשֶׁר אֲדַבֵּר אֵלֶיךָ אֹתוֹ תַעֲשֶׂה:
Hashem says go with them

Bamidbar 22:22

וַיִּחַר אַף אֱלֹהִים כִּי הוֹלֵךְ הוּא וַיִּתְיַצֵּב מַלְאַךְ יְהֹוָה בַּדֶּרֶךְ לְשָׂטָן לוֹ וְהוּא רֹכֵב עַל אֲתֹנוֹ וּשְׁנֵי נְעָרָיו עִמּוֹ
Hashem got upset that he went, and sent an angel to stand in his way

Bamidbar 22:35

וַיֹּאמֶר מַלְאַךְ יְהֹוָה אֶל בִּלְעָם לֵךְ עִם הָאֲנָשִׁים
The angel said to Bilaam "go with the men"

Rabbi Schwab then points out that the escorts were with Bilaam both before and after the encounter with the angel, but seem to be absent at the encounter:
Bamidbar 22:21

וַיָּקָם בִּלְעָם בַּבֹּקֶר וַיַּחֲבשׁ אֶת אֲתֹנוֹ וַיֵּלֶךְ עִם שָׂרֵי מוֹאָב
Bilaam went with the Moabite ministers

Bamidbar 22:35

וַיֵּלֶךְ בִּלְעָם עִם שָׂרֵי בָלָק
Bilaam went with Balak's ministers

Rabbi Schwas explains as follows:  Bilaam was only permitted to go in the first place for his own honor, and was not permitted to go with the desire to curse the Jews - Rashi to 22:20

אם לקרא לך: אם הקריאה שלך וסבור אתה ליטול עליה שכר, קום לך אתם
"If they have come to summon you" - if the summons is for you, and you assume to be rewarded for it, then go with them

But Bilaam ignored this caveat of the instructions to go, and instead went with excitement to curse Israel.  He was so excited and personally invested in the mission that he actually sped ahead of the honor guard that was with him!  Seeing that כי הולך הוא, that he was going alone, that he was excited to go curse the Jews, Hashem sent an angel to stop him.  The angels instructions were not to turn around - the instructions were to go with the escort, meaning to go for the honor that they are according you and not for the sake of the mission itself.
So, the ministers were indeed not there, as Bilaam had sped ahead in his excitement.  This itself was the reason that his going was problematic.


Should we release the security issues we found in our product as CVE or we can just update those on weekly release notes?

Question: We are a vendor providing a product that is being used in enterprises. We know that those companies having periodic CVE scans on products they are using part of their vulnerability management process. My question is, do we have to raise a CVE if our own security researcher found a vulnerability in our product or we can just raise this vulnerability in the weekly security updates we publish in our official website?
Comment: It seems you sell your product. Do you have a reasonable way of communicating the information to all your clients, and only to your clients? (i.e. by sending an e-mail instead of publishing an announcement on your website). The answer to this question may help you choose between the answers below.
Answer: You can do either, but I recommend applying for a CVE so that customers who get threat intelligence feeds are more likely to notice the issue and expedite a patch. Assigning a CVE also makes it easier to reference a specific vulnerability in general communications if you need to later. It's also a signal to your customers that you take security transparency seriously.
CVEs are assigned and managed by MITRE, and you can use the CVE application form to make a request.
Comment: @eckes Oh, CVE assignment turnaround is generally fairly quick. I've had them assigned within hours before. Longest wait I ever had was 6 days but there were extenuating circumstances (two people responsible for assigning CVEs at MITRE were sick at the same time).
Comment: Domyou have first hand experience with applying as a Vendor for a commercial product for a cve at the root cna?
Comment: @eckes I've never done the process myself, but I've worked with and for vendors that have applied for CVEs and from what I could tell the process was no different than if a 3rd party applied for it.
Comment: Yes, should be the same process, the question is just how fast was the turn around and what happens after repeating it a few times a year
Comment: Good to know, sounds like this has improved!
Comment: I can affirm that the people at MITRE are very dilligent, in my case they even notified me of a mixup with identifiers on another site. Regarding getting CVEs registered as a vendor, I am sure they will be happy to receive the info, no matter the source.
Answer: It would be helpful to publish the CVE so that others know it's necessary to update: as you said, they can see it in threat intelligence feeds (or CVE scans) instead of having to read the changelog of every update to decide whether they need to update.
Additionally, as a pentester, it helps us a lot in our work. If we find SAPConnectorDeluxe 4.1.39, the first thing we do is check a CVE database for any vulnerabilities. Even if the software is proprietary and in use for only a few companies, it is useful for us to know the risks of running that software so that we can advise the customer correctly.
It also tells us how frequently and what kind of issues are being found: if we see that a small software component had 10 buffer overflow vulnerabilities in the past year, we know the developers don't get the time to include security in their development process. In such a case, it's very likely that more vulnerabilities will be found, or are already found by malicious parties.
Submitting CVEs is not common if the software is only used internally. If we find custom software, we do some analysis (depending on how much time we have) and advise to have someone review its security more thoroughly. Info about internal products would not help anyone outside the company, so there is no need to publish it to a central database like CVE.
Comment: This answer spends quite a bit of time discussing a reason not to file a CVE, which is that too many can make you look bad. I think the benefits of demonstrating your commitment to security outweigh this, but this answer won't help convince anyone of that.
Comment: On a similar note, too many CVEs can also make you an attractive target for hackers.  If you patched 10 buffer overflow vulnerabilities in the past year, then a hacker can see this as likely evidence of an 11th, and focus a lot more energy on you than he would otherwise.  Even if your actions showed commitment to security and you patched all of your overflow vulns, the extra attention is likely to expose an unrelated problem.  So, at a point, too many CVEs  themselves can become a security liability.
Comment: To complement the above comments, I have the feeling sometimes CVEs are (mis)used  as free advertisement, to sneak the name of an otherwise unknown product in thousands of feeds.
Answer: You are not required to request a CVE, but you are free to do so when you think it will be benificial.
A CVE is just a central number that identifies a vulnerability, which can assist when communicating about vulnerabilities. CVE's are particularly helpful when there are multiple parties involved. Anyone can request a CVE in your product, but in my opinion it looks better if you do it yourself before somebody else does.
Comment: Small remark: You say "it looks better if you [request a CVE for a vuln in your product] yourself before somebody else does", but that sounds like the developer of the software should always snatch up the CVE before anyone else can request it. To me, that would feel like taking part of the credit. I'd rather say it should be the person who found it -- which in this case is the company itself, but it often (usually?) isn't. Not sure how you meant it.
Answer: I think the most important question is if your product comes with an auto-updater.  If it auto-updates by default, then a CVE can sometimes do more harm than good by putting your product into the realm of awareness for many hackers who may otherwise not know you even exist.  They can see your CVE history, and get a good feeling about your security posture.  If they see a lot of fixes for "amature" mistakes, then your product might easily come under the scrutiny of people who know how to find the more obscure stuff that you may have otherwise gotten luck enough to avoid.
Also, products that are unlikely to be patched even if you release a CVE can do more harm than good.  Most IoT devices never get patched, so, CVEs just tell hackers which ones are easy prey.
In contrast, if your product typically requires a manual update that is likely to happen if you release a CVE, then you should probably do it.
Answer: If this is a really critical issue, then you might patch the issue and keep it secret for as long as possible.
Then the customers have a longer time frame for applying software updates.
Also make sure to use as much binary obfuscation as possible, in order to hinder "differential reverse engineering" after delivering the patch.
Comment: By keeping it secret, there is not one effect (the one you mention) but two effects: yes, customers have more time to upgrade because bad guys *might* not realize there is a vulnerability, but also, customers won't be aware there is an issue and might go "meh, we don't need these new features and didn't notice any bugs, no need to spend sysadmin hours to upgrade it". That said, you did get me thinking: it might be good to, instead, communicate it to customers privately before making it public (as is done with responsible disclosure).
Comment: @Luc: Just grabbing a random recent CVE, CVE-2018-7183.  The title is "Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array."   That is not precisely "enough detail to exploit an issue" but it certainly is enough to give attackers a huge headstart.
Comment: @BenVoigt just a remark, if you look at open source CVEs there are by nature more complete and detailed. Commercial vendors might have a policy not to disclose details. Oracle for example is notoriously bad.
Comment: @Luc: I don't think that Mike is suggesting keeping the existence of a patch secret.  It's the details of the issue that are kept secret.  Customers should be motivated to install a patch listed as "fixed remote code execution vuln" based on the severity, without understanding the bug itself.
Comment: @BenVoigt CVEs usually don't include enough detail to exploit an issue, only in some cases they're later updated to link to a page with more details. But indeed, Mike might have meant that, I don't know.
Comment: I suggest to write something like "critical bug fixes, improved security" in the release notes. Most CVEs I have seen provide way too much details for a fast disclosure.
Answer: Few companies will apply patches immediately, most will have some quality control and evaluation before any update is put into their systems.  The CVE definition allows them to know what vulnerabilities are in the current version of the software.   Then can then evaluate that vulnerability and make an informed choice of when they will apply the update.


Is the CSMA/CD protocol active in modern ethernet networks that use LAN switches? If it is active, does it ever detects a collision?

Question: I am interested to know if the CSMA/CD protocol is still active in modern Networks and if it is active why and what is his role now?
Comment: Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
Answer: Short answer:
The support is still present but it is generally only used when legacy equipment is connected, either hubs or very old (or embedded) network interfaces that operate at 10Mbps only and do not support autonegotiation.
Long answer:
CSMA/CD is a protocol used for communication over half-duplex communications media.
10BASE-5 and 10BASE-2 links are half-duplex by nature but are extremely rare nowadays. Hubs (aka multiport repeaters) are also by their nature half-duplex.
10BASE-T, 100BASE-TX and 1000BASE-T links are full duplex at the electrical level but for backwards compatibility and to allow the use of hubs they support a half-duplex mode where simultanious transmission is treated as a collision.
Autonegotiation allows devices to automatically choose a speed and duplex, it was introduced alongside the 100 megabit standards. If one end supports autonegotiation and the other does not then for compatibility reasons the end with autonegotiation will default to half-duplex mode. As a general rule devices that support 100Mbps and higher support autonegotiation, 10Mbps only devices do not.
In principle you can run full duplex without autonegotiation by manually specifying full duplex mode on both ends of the link but in practice that way lies pain. It is very easy to end up with an inadvertant duplex mismatch which results in a link that works very badly in ways that are diffiult to troubleshoot.
Answer:
I am interested to know if the CSMA/CD protocol is still active in modern Networks and if it is active why and what is his role now?

What is your definition of "active"?
If you are talking about is it in common use, then no it isn't. Most modern networks and devices utilize interfaces that are capable of establishing a full-duplex connection. CSMA/CD is not used in full-duplex operation.
However, if by active you are asking if it is present, then the answer is yes. Up through 1000BASE-T, half-duplex operation is supported. CSMA/CD is used for any half-duplex link.
Comment: @Zac67, since that was where I was defining CSMA//CD as *present*, there is no denying it is *present* in 1000BASE-T. It doesn't matter that there are very few cases where it is actually used,  it is still present.
Comment: @Zac67, sorry, but you are wrong. There are a number of devices where you can set 1000/half in the configuration, simply because it is *present* in the standard. Just because something isn't used doesn't preclude it from being present. I have a bandsaw in my workshop; I can use my workshop without using my bandsaw, but that has no bearing on if the bandsaw  is present in my workshop.
Comment: Half-duplex communication has been _defined_ for Gigabit Ethernet but there are no devices around actually supporting it. In practice, half-duplex can only be used for 10/100.
Comment: My point was that it is _not present_ for 1000BASE-T (or -X for that matter) - real hardware simply doesn't support it. It supports HDX for 10M or 100M links but not for 1G.
Comment: Care to share which devices? I'd been looking at datasheets for months and couldn't find anything.
Comment: @Zac67, the ones I have seen have all been 'nix based. Search on the web for "supported link rates 1000baset/half" and you should be able to find output from devices that support AND advertise it. But whether some devices support it or not, it is still *part of the standard*.
Comment: Let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/65063/discussion-between-zac67-and-ylearn).


Are runed skills always better than non-runed?

Question: Is there any reason to not rune skills?  From their descriptions they simply add additional effects (fire, greater area of effect, adds teleport, etc) and don't suggest any sort of trade-off.  They don't seem to lose any of their original impact, but I may not be noticing among the hack-and-slash action.
Answer: If you have a rune, it is always better to use it. Blizzard CMs have confirmed that there is no reason to choose not to rune a skill, it is merely an issue of what rune to use.  Of course, you might still want to use a skill before you have unlocked any runes for it, since a non-runed skill can still be "better" that a different, runed skill.
Source
Answer: This depends on what damage type you are doing and what the runes do vs what the spell does naturally.
For example. You have lots of gear that give additional damage to Lightning Damage. You are deciding on what rune to get for "Spell A". The base spell does Lightning Damage. None of the runes do Lightning Damage, but you really want the ability. Well, use no rune.
Another example. The base ability compliments your current build better than any of the runes. Use the base ability instead of the rune.
They are not always better. Just depends on your build and gear. However, they are most of the time better.


What is the term for two file formats that describe the same amount of information?

Question: I am working on file formats conversion. Some of them can be converted back and forth to others without losing any information (fields or precision of the numbers encoded), others file format do not take into account some data or meta-data or use approximated values.
I was looking for a term to describe the first case, where two formats describe the same amount of information. I'm aware of the term isomorph that seems to describe the case quite well but I couldn't find any reference to any isomorph file format. Is there any other term used for describing the case?
Comment: What makes you think there is such a name?  There are many more concepts than there are names.  That's the beauty of language; we can describe interesting concepts that we don't have a single-word name for, and we're not limited to only those things that we already have a word for.
Comment: @D.W. I am not assuming that it exists am just looking for it!
Answer: I think that many programmers would look at it in terms of the conversions between the two formats, and say that each format can be converted to the other losslessly, and that it's possible to make a round-trip without losing any data. It's not a standard usage, but if you said that the two formats were round-trippable wrt each other, you would probably be understood. That said, you should still explain what that means!
Answer: Isomorphic file formats implies semantically that the formats have analogous data structures but no necessarily the same fidelity.
Perhaps this what you want to say: two file formats that have the same (data) fidelity.


How to comfortably carry equipment when running?

Question: I am a distance runner, and sometimes go running on trails where there aren't likely to be many people. Since I have type-1 diabetes, I must carry a blood glucose tester and a source of quick sugar with me, particularly since exercise can lower blood sugar. While this all amounts to a pretty small amount of equipment, it's more than fits comfortably in the pockets of my running shorts. What are some ways to carry this gear without it impeding running or causing discomfort? We're talking about maybe 200-300g of total mass, though space for a little bit more would not be bad.
Answer: SPIbelt! I don't run without one. They're also frequently used by diabetics as well as runners. They stretch, so they're tiny, but expand to hold a surprisingly large amount of stuff.
Comment: +1 Definitely worth the money! You can't believe how far this thing will stretch if required
Comment: looks nice but seems to be only available in the US or for very expensive in the UK :-(
Comment: Belts always ride up over my stomach which is pretty uncomfortable and then they flop around.
Comment: @Joe the SPIbelt doesn't bounce! So there really isn't any flopping around. ;)
Answer: I use a small camel bag (not too full) for that. Not ideal for reaching the gels but you got liquid as well something you really want on long run.
Comment: How comfortable are they around the shoulders or do they tend to fit well (so it doesn't sway or rub)?
Comment: @IvoFlipse I personally have a biking edition camelback that I use and it's very comfortable
Comment: While biking that is.
Comment: The body movement when biking is very different from when running though.
Comment: I use it on running as well biking and they are very confortable and fit well.. I have the camelbag branded original version http://is.gd/qgj8Iq
Answer: FuelBelt! It carries water bottles and has various pouches the can hold a gel, a cellphone, or a small camera. I bought the four-bottle trail-runner model because of the extra pouches, and in case I ever need all four bottles. I haven't needed more than two bottles, but it's nice to have the option. Instead of a glucose snack or in addition to it, you could have a glucose drink in one bottle. During the summer, I fill one bottle with a sports drink and another bottle with plain water. Each bottle holds 8oz. With four bottles, that's a total of 32oz (1 quart). My belt has two gel pouches, and two zip pouches. My mobile phone easily fits in either of the zipper pouches, and it is comfortable. My only complaint is that my phone tends to make my belt want to rotate slightly, but otherwise, I love it! I don't go running in the heat without it. If you put similar shaped items in the zipper puches, then it won't have this problem.
Answer: For a jury-rigged setup (if you'd like to get started without spending any money), you can also simply use the belt loop on your shorts.  I attach a climbing hook to my belt loop, tie one end of a string to the hook, and attach the other end to whatever it is I'm carrying.  I used electrical tape to secure my insulin pen, and another knot to secure my water bottle (a 16 oz that I keep in my right pocket).
Answer: I personally run with amphipod's runlite belt with or without the bottles [depends on the length of the run. Has a pouch and a little pocket in the front. Holds my phone, keys, id,
Comment: +1 The combination of a bottle holder and a pocket is pretty decent


Why don't karateka practice ground-fighting and takedown defense?

Question: Why don't karateka train in any kind of ground fighting or takedown defense? Karate contains takedowns, throws, leg sweeps etc. yet I've never seen anyone teach sprawling in karate and getting up from the ground and back on your feet isn't practised in training very much.
Answer: TL;DR - Karate itself doesn't include much grappling because ancient karatekas were expected to be proficient grapplers and would regularly cross-train in both karate and wrestling. Karate was transmitted, but not the wrestling, leaving modern karate with very little grappling defenses.

Other people have posted great answers as to why most instructors do not include ground fighting in their curriculum. Some of these are heavily oriented towards taekwondo which, while it has some roots in Japanese karate, it was created at a time when grappling had already been phased out. Thus, I feel it is important to add an historical perspective to this discussion.
While karate is definitely the most well know Okinawan martial art, it is not the most ancient, nor the most popular, at least historically. As in many other Southeast Asian countries, folk wrestling has had an incredible influence on the development of martial arts. Known as tegumi in Naha, or mutō in Tomari and Shuri, Okinawan folk wrestling includes grappling, joint locks, pins and strangles. Ancient karatekas were thus generally expected to be proficient in wrestling, the "primary" combat form of the island. Like most modern MMA gyms, they would alternate between karate and wrestling training and aspire to be well-rounded martial artists.
In the early 1900's, a reform of Okinawa's school curriculum tried to integrate karate into the physical education program of the island. Karate started evolving towards "fitness" rather than "self-defense", and the grappling side of the art was essentially removed from the schools' curriculums to avoid injuring the children. This process was further amplified when Funakoshi Gichin imported karate to Japan in the 1920's, as he tailored his shotokan to Japan's intellectual elite.
In most karate katas, traces of grappling can still be found. Tuidi-waza, or seizing hand techniques, are integrated into the forms to indicate ways of transitioning from striking to grappling. As I've mentioned earlier, ancient karatekas were expected to be proficient at grappling, and would thus know how to best take advantage of these opportunities.
However, most modern lineages have "forgotten" the grappling aspect of karate. Okinawan styles generally continue to train in tuidi-waza but, as most instructors are not proficient in tegumi, most schools simply stick to the striking aspect of karate. Japanese styles often eschew tuidi-waza altogether, despite vestiges of it being present in their katas.
For a slightly different take on this topic, I would suggest reading one of sensei Iain Abernathy's short article on the subject, in which he also provides a few interesting references.
Answer: I can't speak for Karate, but Taekwondo has similar characteristics to Karate. In TKD, we don't emphasise ground-fighting or takedowns, because we simply don't have the time in one or two hour-long sessions a week to cover them.
This is often rationalised by saying that TKD is about keeping your assailant at a distance, hence the emphasis on kicks. In self-defence terms, we teach our students that awareness is vital. In other words, don't let any assailant close enough to actually grab you!
Equally, as the emphasis in TKD is on fighting on your feet, it is conceivable that instructors aren't confident enough in grappling or ground-fighting techniques to teach them effectively.
In summary, my reasons are:

Available teaching time
Rationale or philosophy of the art
Knowledge or experience of the instructor
Answer: It is mainly going to come down to the instructor and the school.
For both karate and similar arts, the emphasis is on striking, and there is little emphasis on what is commonly called the "ground game". This is not a knock against the art, it is just the way that it evolved.
For many typical instructors, they spent a considerable amount of time learning and improving their technique, as well as learning how to teach and (hopefully) learning how to run an effective class and school. The more complicated the curriculum (weapons, forms, etc), the more time you have to spend on that aspect of it.
Unless the instructor goes outside their normal range and seeks out the groundfighting/grappling arts, they simply don't have the knowledge to teach it, much less teach it effectively. The common mantra of teaching to avoid the ground is somewhat of a rationalization, as if you have someone that is skilled at a ground based art, if they get in close enough to get hold of you, then you are most likely in a world of hurt, especially if they do manage to get you down.
The most common recognized single art that encompasses aspects of both the striking and joint lock/throws along with grappling is hapkido. If that is not an option, if you want to get the ground training, then you will need to find a bjj or similar style school to learn.
Comment: Good answer. It evolved to be what it is. It's not a complete combat system, nothing is on its own. This part made me chuckle though, "especially if they do manage to get you down", they would, easily, because the karate folk aren't training takedown defense. And keeping distance isn't a defense. Remember the Gracie Challenge?
Answer: True Karate, like Taekwondo, is a complete fighting system, with grappling, striking, weapons, pressure points, meditation, and more.  It's a complete lifestyle, really.  Every aspect of one's training relates to life outside the dojo in some way, whether it is about respect to another, self-defense, competition, or what one does when no one is looking.
But, that is a tall order for most people.  Who has the time to do all that, and still get in time for baseball, college, work, family, commuting to work or school, testing, girl/boy friends, and walking the dog?
Today's lifestyle is a very busy one for most people, and as a result, the classical martial arts have had to adapt as well, or else they lose students.  Taekwondo nixed everything for the Olympics and doesn't do anything other than sparring (and that strange thing that nobody really understands, but we call it forms, hyung, poomsae).
And Karate is no different, and did the same.  Except, by and large, they still retain their forms (although, it's common to find the same students here who don't have a clue about what they're doing in kata).  Some still manage to get in self-defense practice.  But that will change, come Tokyo Olympics, and - like Taekwondo - many schools will drop everything to focus on Olympic requirements.
As a result, our styles have become nothing by niche sports, and useless for their original applications.  Did you know that boxing contained grappling and throws?  That wrestling contained strikes?  That Karate and Taekwondo contained weapons, grappling, pressure points, and throws?  All of these styles nixed one element or another - or several - so that it morphed into what we have today.
The challenge for the serious martial artist is to find a school which embraces all or most of these original elements, and with less of an emphasis on any one of these things, like sport.
As classical-styles-now-turned-sport matures in the future, the classical ways will be forgotten entirely, as today's students become tomorrow's teachers.  If today's students aren't taught, where (and when) will they learn, and what will they teach?
You wait.  We in Taekwondo went through this, as we saw the ruination of our style collapse into this crap we call Olympic Taekwondo, and it is dragging in the other TKD styles like ITF and ATA into it.  We are all betting the same will happen to Karate, and within one generation, what you will see in Karate will not look a bit like it looks today; indeed, what we see in Karate today looks nothing like it did a generation ago.
Perhaps my observations will give you some insight for what you are in for.  In my town in Long Island, NY, there were 80 TKD schools within a 15-mile radius of us.  Annually, we competed with each other in nearby school gymnasiums.  We competed in striking sparring, some grappling sparring, weapons, and forms.  That was 20 years ago.  Today, there are about 150 by several schools' accounts in that same area, and all except maybe 5% of them focus only on Olympic Taekwondo.  And some schools live no more than 2-3 years, then go out of business, usually because the instructor has no sense of business or can't keep students.  Granted, part of their problem is saturation.  And Karate schools?  They estimate about 40 schools in the same area, and about half that 20 years ago.  Those 40 schools today are also only doing competitive sparring: they do not do self-defense except as a cursory adjunct to their regular classes and nearly always involves the "here, grab my wrist" thing which is so ubiquitous.  And no one ever falls on the floor.
The Kukkiwon - the governing body of the style of Taekwondo typically attributed to Olympics Taekwondo - is now officially a sport (and has been informally called a sport for the past 15 years) by - guess what? - The Ministry of Sport in South Korea.  We don't call them Taekwondo-in anymore, we call them players.  And refereeing is fast becoming a serious role in Taekwondo life.
Comment: Yes.  Today's boxing, commonly called "American Boxing" is an adaptation to the Marquess of Queensbury rules, with notable technical differences having to do with weight classes, size of ring, and the use of umpires (we call them referees).  But Queensbury superceeds London Prize Ring rules, which allows throws.  In fact, Queensbury rules explicitly forbid wrestling and throws, a notable difference between the two sports.

https://en.wikipedia.org/wiki/London_Prize_Ring_Rules
Comment: I'll probably get kicked for introducing irrelevant (to the OP) details, but here is more interesting info on boxing:

https://www.britannica.com/sports/boxing/The-bare-knuckle-era#ref403493
Comment: Very interesting answer! ' Did you know that boxing contained grappling and throws?' caught my attention, do you have some reference for this? Would like to know more.
Answer: I did Kempo when I was at school for about seven years. I can count on one hand the times we did ground fighting. It was there, but very rare.
Your average dojo today (and for a couple of decades) is more like an alternative to pilates or yoga for the mass of students who attend. They likely offer a competition track for those wanting a challenge, but the old martial side of things has been lacking for a long time. You can say nearly the exact thing for tkd.
WTF rules tkd is the number one "martial art" in China because of the ability to get medals for the State so the State heavily promotes it.
Now there is MMA which is feeding interest to new generations but MMA is just the new boxing, it's a heavily regulated sport where much of what traditional martial arts taught is not usable in the ring.
TKD sparring, what you see in more traditional organisations, bars grappling. So you can't grab someone's leg. That's because sparring was designed to train the use of the legs and arms in a combat situation but it was never the complete art. TKD has little grappling to begin with, but there should be a category of sparring where it can be used to remind people that in a real fight their wonder technique might be defeated by something as simple as their leg being grabbed before they can deploy it properly. You see this in MMA situations where grapplers, BJJ being the popular one, move in and shut down strikers before taking them to the ground. There are several techniques which could possibly prevent this but sport oriented clubs tend not to train to do so.
I should refrain from saying sport orientated because the real issue is that these clubs are too insular. They only train to fight against their own style and if that style has already limited what techniques it uses, like next to no grappling, then students are being given false confidence that their style works.
Answer: From what I know, KARATE is not a fighting stlye.
Karate is the Japanese translations of "Fighting with empty hand".
Please see Karate more as an concept then as a fighting style. In Karate concept as long as you fight with your empty hands, no matter what you do, is karate.
From the Japanese term point of view, even taekwondo is consider to be a karate fighting style.
Now. About grappling and sweeps.  A fight can happen on a long, medium or short range.
Most of the styles promote the long/medium distance. Reduce the risk of immediate danger for the practitioner plus add an extra reaction time to block/duck/run. In real life, the fights are BIG vs small.  Not most people have the physical/mental straight to sustain a close quarter combat ( see a TKD fighter vs a Judo fighter) and is much easier to promote the DEFENSE part of the Art, just because  the distance offer time and plenty of chances to escape.
Remember that the Art was adapted to serve for Self-Deference not Attack.
There are Arts that have a more complete approach. Kudo Daido Juku for an example.
Have everything from the distance point of view, both fist/kick and grappling/trows.
Now. For those who think to the Art as a sport, as Tkd, Judo, Vovinam Viet Vo Dao , etc.  From competition point of view, is much more danger. You promote an Art. Is hard to show blood. In UFC is FIGHTING Competition. No Art involved. Marketing.
How many techniques are not banned for being to brutal?
Comment: The "empty hand" definition of karate is fairly modern and originates in Japan's militarization in the 1920s. Prior to that, it was pronounced the same, but written with kanji that better translated as "china hand", and referred to the Chinese influence on Okinawan martial arts. It was common practice to simply call it "te", or to affix regional prefixes to differentiate between styles. Thus, ancient karateka did not practice "karate", but rather "Shuri-te", "Naha-te" or "Tomari-te". The term "karate" is the Japanese equivalent of "kung fu" and, likewise, it now covers many different styles.


Hidden Features of `screen`

Question: Since I use the *nix command screen all day, and I couldn't find anyone starting this question, I figured it should be started. You know the drill: community wiki, one answer per features so we all can vote.
Comment: screen is so useful it belongs on all the sites:  http://stackoverflow.com/questions/70614/gnu-screen-survival-guide
Answer: I love using it for connecting to serial consoles, i.e.
screen /dev/ttyS0 19200

This command simply opens up a connection to serial port 0 (ttyS0) with a baud speed of 19200
Comment: And truly one of my favorites.  No need to deal with, or configure, minicom, conserver, etc.  I felt like a little kid in a candy store when I discovered this.
Comment: Absolutely - it's nice to have a screen session open, split into two windows, with both USB-Serial dongles visible.
Comment: this is one of my favorite things to freak people out with, truly one of screen's least expected features
Answer: The best feature of screen is Byobu (formerly screen-profiles) which comes with Ubuntu by default since Jaunty: https://launchpad.net/byobu
It's a configuration manager with very nice defaults, tons of status notifications and useful keyboard shortcuts (i.e. f2 for new screen, f3-f4 for prev/next etc.)
I really don't go anywhere without it anymore :)
Answer: From KTamas's amswer: More than one person can use the same screen, i.e. if a friend of yours ssh into your computer, then he can connect to your screen. It's great when two or three people are working on the same projects.
Comment: This is much better for following what remote support users are doing, and killing their session if they're upto no good!
Answer: Not exactly a "hidden feature"; but a properly setup .screenrc file can make a world of difference.  One of the better examples out there can be found by googling screenrc and 'brad sims' - he has an excellent file to tinker with.
that said, my favourite setting would be bindkey:
# bind F7  to detach screen session from this terminal
# bind F8  to kill current screen window.
# bind F9  to create a new screen
# bind F10 to rename current screen window
# bind F11 to move to previous window
# bind F12 to move to next window
bindkey -k k7 detach
bindkey -k k8 kill
bindkey -k k9 screen
bindkey -k k; title
bindkey -k F1 prev
bindkey -k F2 next

Comment: Considering that ctrl+a is used too often outside of screen (beginning of line in bash anyone?) I like this.
Comment: ctrl+a/ctrl+e for moving the cursor, but also when minicom is running in a screen. Ctrl+a,a,o for options...
Answer: I can't remember who I stole this from (someone on dotfile.org). I've modified it slightly for ssh:
#!/bin/sh
# scr - Runs a command in a fresh screen
#
# Get the current directory and the name of command

wd=`pwd`
cmd=$1
shift

# We can tell if we are running inside screen by looking
# for the STY environment variable.  If it is not set we
# only need to run the command, but if it is set then
# we need to use screen.

if [ -z "$STY" ]; then
        $cmd $*
else
        # Screen needs to change directory so that
        # relative file names are resolved correctly.
        screen -X chdir $wd

        # Ask screen to run the command
        if [ $cmd == "ssh" ]; then
                screen -X screen -t ""${1##*@}"" $cmd $*
        else
                screen -X screen -t "$cmd $*" $cmd $*
        fi
fi

Then I set the following bash aliases:
vim() {
        scr vim $*
}

man() {
        scr man $*
}

info() {
        scr info $*
}

watch() {
        scr watch $*
}

ssh() {
        scr ssh $*
}

It opens a new screen for the above aliases and iff using ssh, it renames the screen title with the ssh hostname.
Cheers z0mbix
Comment: :o. Did you lift and adapt it from me? https://gist.github.com/137214
Comment: No, I think it was from a last.fm staff member who blogger about it once.
Answer: One thing I find useful is that screen can emulate a larger width than your terminal. I find this useful if I'm using less to real log files, and I don't want the lines to wrap. Using:
Ctrl-A:width -w 999
I can set screen's with to be wider than my terminal, and log lines in less won't wrap.
Comment: FYI, the less option `-s` will tell it not to wrap lines. You can use `Left` and `Right` to scroll the lines.
Answer: The ability to change the control key with -ethat when starting screen.  I use it so I can nest screen sessions inside each other.  Example: "screen -e ^w^x" makes the control key ctr-w.
Answer: One nice feature: you can use backtick to pull in extra info for display in a caption.  For example, I have a script that output a one-line summary of new mail counts in various folders, and I have that appear in the bottom line if my screen session along with the hostname with a config that looks like this:
backtick 1 15 15 /home/waltermundt/bin/newmail

caption always
caption string "%{.kW}%1` example.com %{.bW}%-w%{.rW}%n %t%{-}%+w %{.gW}%h%{-}"

The key is the %1` bit, which refers to the output of backtick job 1.
(I use hardstatus as the xterm title string and have it set differently, thus the use of caption instead of hardstatus alwayslastline.)
Answer: Not a "hidden" feature, but the ability to share a screen session with another active user is very useful.
There are complicated ways to set up screen sharing, including access control permissions and user name management.  What I most often do with coworkers is much more quick & dirty:

Log into machine in question in new window.
Allow anyone to write to my terminal:  chmod 777 $(tty)
Sudo to their account:  sudo su <username>
Share their screen:  screen -x <session>

This doesn't require any advance configuration or password sharing.
Answer: A little cheat sheet I have printed out for myself;
(Note: Everything is preceeded by Ctrl-A)
A: rename a window
": show a list of windows
d: detatch session
And screen -D -R to deattach and reattach a running session (in case you somehow lose access to your session).
None of these are really hidden features, but these are the features I find to be the most useful.
Answer: It's a core feature, but of course the best is Ctrl-A: to talk directly to screen.  : screen -t title ssh hostname etc.

Hidden Features of `screen`