How to copy file/folder permissions and ownerships from one folder to another (recursively)
How to copy only file attributes (metadata) without actual content of the file?
What's the difference between TRUNCATE and DELETE in SQL What's the difference between TRUNCATE and DELETE in SQL?  If your answer is platform specific, please indicate that. What are the meaning and possible origin of "word!" and "word up"? Why does a neon lamp indicator on a power strip switch flicker in the dark? Neon lamp indicators embedded in power strip switches indicate whether the switch is ON or OFF. When the neon lamp is ON in a dark environment (lights of the room are off), the lamp begins flickering and it sometimes goes off for a few seconds. When I switch the lights of the room on, it stops flickering and remains bright. Even when I unlock my phone in the dark near the lamp, it stops flickering! Is the light-making-mechanism in neon lamps affected by the light intensity of the surrounding environment?  UPDATE: I captured my observations with my iPhone and uploaded it to YouTube. Here is the link of the video:  All the lights of my room were turned off. There were no plugs connected to the power strip. The only source of light was the screen of my MacBook Pro, which was not plugged in.  I increased and decreased the brightness of the computer screen during the video.  I then produced two additional light environments using my phone. What are the current travel restrictions on individuals entering the United States from regions affected by Covid-19? Reduce gap between subfloat and subcaption Chatroom owners can star their own messages I was able to star my own message by pinning it and unpinning it.  Pinning a message adds a star, even to your own messages, but when the pin is removed, the star remains. $M= \{ A \in Mat_{2 \times 2}{\mathbb{R}}| \det(A)=1 \}$ is homeomorphic to $S^{1} \times \mathbb{R}^{2}$ Can I recover app data after the phone has been Factory Reset? Without remembering application data, I reset my Galaxy S3 to factory state. Now, I lost data for one expense manager app. Is there any way to recover the data? My character has a bite attack from his race.  What happens if he gains another bite attack from class abilities or spells?  Does the damage increase?  Can he make more than one attack?  Or is it simply that only the better version applies?  I would prefer answers from a Pathfinder context but 3.5e is also acceptable. I just noticed that the  user edited a ~1 year old  of mine. As you can see, the method call was changed from getSfGuardUser to getGuardUser:    Now I checked the documentation and it seems that the edit is correct.  But how did Community know about that? As far as I know, it is an automated process. Does it have a reference of all possible APIs of languages/frameworks (which seems very unlikely) or is there a routine admins can trigger, for replacing content? Or is it a secret? Could I have a hint for testing the convergence of the following series please?  $$\sum_{n=2}^\infty\frac{1}{(\ln n)^{\ln n}}$$  Edit  The integral test does not work because $\int_1^n\frac{1}{(\ln x)^{\ln x}}dx$ has not an elementary primitive.  Thank You. I have a very large codebase (read: thousands of modules) that has code shared across numerous projects that all run on different operating systems with different C++ compilers. Needless to say, maintaining the build process can be quite a chore.   There are several places in the codebase where it would clean up the code substantially if only there were a way to make the pre-processor ignore certain #includes if the file didn't exist in the current folder. Does anyone know a way to achieve that?  Presently, we use an #ifdef around the #include in the shared file, with a second project-specific file that #defines whether or not the #include exists in the project. This works, but it's ugly. People often forget to properly update the definitions when they add or remove files from the project. I've contemplated writing a pre-build tool to keep this file up to date, but if there's a platform-independent way to do this with the preprocessor I'd much rather do it that way instead. Any ideas? Lecturer with anxiety. How to survive in academia? I've been a long time member of academia.SE but I created this alt account because the question is a bit embarrassing. I finished my PhD 4 years ago and after a 2 year postdoc at a different university secured a contractual lecturership. During my PhD I never realised I had fear of public speaking, because I always felt secure presenting in front of my supervisor. Even at conferences, his presence in the audience was enough to keep me relaxed.  Fast forward to my postdoc, I was mostly working and publishing by myself. So, even if I had to present something it was to my coauthors, with which I am okay. But as a lecturer doing research part of my time, I am involved in projects and seminars where I am expected to present my latest work. Being on my own has brought out my inner anxiety, so much so that I choked during a presentation, had to drink water to calm my nerves and apologise for my breathlessness and slurred speech. That was the most embarrasing thing in my life. Please note that the anxiety is not the result of me not publishing or doing research. I have published more than most in my department. Knowing that hasn't helped with the anxiety though. I am constantly making excuses to get out of project presentations and seminar talks. Fortunately, the anxiety is less intense in teaching and I am able to manage.   How do I survive as an academic? Now even conference presentations seem daunting. I can publish exclusively in journals, but how do I get out of giving project and departmental presentations? How can I politely refuse to present without revealing my situation? Or better yet, how do I fix the whole thing? That one bad presentation has really messed me up. Is there any difference between "offense" and "offence"? "Offense" vs. "offence", which is more correct? If both are correct, are there any differences in shades of meaning and/or usage? I noticed that when I had a helium filled, latex balloon inside of my car, it moved forward in the cabin as I accelerated forward. The faster I accelerated forward, the faster the balloon went from the back of the car to the front of the car. The balloon didn't have a string.  This became a game with my 4 year old as we drove home. We figured out where the balloon would go based on how fast I accelerated, turned corners etc.  I expected that it would act a lot like the water in a cup does, but it was the total opposite it seemed.  What forces caused this behavior?  I assumed it has something to do with the fluid dynamics in the closed cabin, but I can't figure it out. The question  got me curious and thinking about the following:   For which $n$ and $k$ are there nontrivial homomorphisms from the symmetric group $S_n$ to the cyclic group $\mathbb{Z}/k\mathbb{Z}$ of order $k$? I'm thinking it might be an open problem. Is this a problem with a known solution? If so, how can we prove it?   Thanks! I am using a Collection (a HashMap used indirectly by the JPA, it so happens), but apparently randomly the code throws a ConcurrentModificationException. What is causing it and how do I fix this problem? By using some synchronization, perhaps?  Here is the full stack-trace:  Exception in thread "pool-1-thread-1" java.util.ConcurrentModificationException         at java.util.HashMap$HashIterator.nextEntry(Unknown Source)         at java.util.HashMap$ValueIterator.next(Unknown Source)         at org.hibernate.collection.AbstractPersistentCollection$IteratorProxy.next(AbstractPersistentCollection.java:555)         at org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:296)         at org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:242)         at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:219)         at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:169)         at org.hibernate.engine.Cascade.cascade(Cascade.java:130) How to install (old) packages for Ubuntu 9.04? Based on some excellent feedback by Mark here (), today I was able to use the vmware converter to clone my production server for a staging server.  However the nic won't come up no matter what I do. I attempted to inistall vmware tools, as I suspect that the fact that it is not installed might prevent the nic from working. (I have the nic set as a vmxnet3 card in the vm settings). The install failed because there were several dependencies missing as well as the Linux headers. Given that Ubuntu 9.04 has been EOL'd, the packages I need to install to get the vmware tools to install are no longer available. I doubt the ubuntu 9.04 install CD has the packages on it.   What are my options? I'd rather not upgrade the version of Ubuntu yet, as the point of the vm right now is to maintain parity with the production server. Might I have better luck resetting the driver to use vmxnet2 instead of the vmxnet3?  Thanks in advance!  Chris Why would a company care about the price of its own shares in the stock market? Google App Engine: Is it possible to do a Gql LIKE query?