I wanted to give permission to sample.txt such as it can only be written by root and executable by the group created by me ( samplegroup) . If any user is added into this group will be allow to execute the file .
I have a ext4 partition and I've set the group owner for all subdirectors to mygroup:  # chgrp -R mygroup /mount/abc # chmod -R g+swrx /mount/abc   My user is part of that group. Inside that partition is a folder who is owned by user 'nobody' and now by the group 'mygroup'. My user is part of 'mygroup'. Here's an ls -l:  myuser@host:/mount/abc/folder$ ls -l drwxr-sr-x 2 nobody      mygroup      4096 Apr 25 12:08 ./ drwxrwsrwx 6 nobody      mygroup      4096 Apr 24 07:57 ../ -rw-r-xr-- 1 otheruser   mygroup    159539 Apr 23 23:44 test.png*  myuser@host:/mount/abc/folder$ groups myuser myuser : mygroup {... a list of other groups also...}   myuser@host:/mount/abc/folder$ rm test.png  rm: remove write-protected regular file ‘test.png’? y rm: cannot remove ‘test.png’: Permission denied  myuser@host:/mount/abc/folder$ touch test.txt touch: cannot touch ‘test.txt’: Permission denied   Note that I cannot delete nor create a file that is owned by a group that my user is a part of.  I guess I don't fully understand how groups work. I thought if you were part of a group then you inherit the permissions of that group. Am I doing something wrong?  Thanks
Changing order of features in shapefile Can I be my own trusted CA via an signed intermediate certificate? Can I get a certificate from a root CA that I can then use to sign my own web server certificates? I would, if possible, use a signed certificate as an intermediate to sign other certs.  I know that I would have to configure my systems in a certain way with "my" intermediate certificate in order to supply information about the chain of trust to my clients.   Is this possible? Are root CAs willing to sign a certificate like this? Is it expensive?  BACKGROUND  I'm familiar with the basics of SSL as it pertains to securing web traffic over HTTP. I also have a basic understanding of the way the chain of trust works, in that web traffic is secured "by default" if you encrypt with a certificate that has a valid chain all the way back to a root CA, as determined by the browser/OS vendor.  I am also aware that many of the root CAs have begun signing certificates for end users (like me) with intermediate certificates. That may require a bit more setup on my end, but otherwise, those certificates will work fine. I guess this has to do with protecting their all-valuable private key for the CA and the disaster that it would be if i were ever compromised.  EXAMPLES        Now, we are definitely not the size of any of those organizations, but they seem to be doing something like this. It would definitely make the management of these certificates a lot more palatable, especially considering one way we are expanding the reach of our e-commerce platform. Zsh says "no matches found" when trying to download video with youtube-dl I downloaded youtube-dl using pip on CrunchBang (a Debian Wheezy distro). When I run   youtube-dl {video URL}   I get  zsh: no matches found: {video URL}   I guess it has something to do with zsh, because I found some users on Arch forums complaining about it. When I switched to bash it worked. I understand that faster-than-light communication is impossible when making single measurements, because the outcome of each measurement is random. However, shouldn't measurement on one side collapse the wave function on the other side, such that interference effects would disappear? Making measurements on "bunches" of entangled particles would thus allow FTL communication, by making observed interference effects appear or disappear. How does such an experiment not:  1) Clearly imply that faster-than-light communication is possible?  or  2) (if #1 is rejected) Imply that measurement of one half of an entangled pair does not cause the collapse of the other half's wave function.  Why doesn't this thought experiment clearly show that if we maintain that FTL communication is ruled out, we must also rule out "universal collapse" in the Copenhagen interpretation?  EDIT: Here is an example of an explicit experiment (though I think experts could come up with something better):  You can entangle a photon with an electron such that the angle of the photon is correlated with the electron's position at each slit of a double slit experiment. If the photon is detected (it's outgoing angle measured), then which-path information is known, and there is no interference. If the photon is not detected, the interference remains.   The experiment is designed such that the photon and electron go in roughly opposite directions, apart from the tiny deflection which gives which-path information. You set up a series of photon detectors 100 ly away on one side, and your double slit experiment 100 ly away in the opposite direction. Now you produce the entangled pairs in bunches, say of 100 entangled pairs, each coming every millisecond, with a muon coming between each bunch to serve as a separator.   Then the idea is that someone at the photon detector side can send information to someone watching the double-slit experiment, by selectively detecting all of the photons in some bunches, but not in others. If all of the photons are detected for one bunch, then the corresponding electron bunch 200 ly away should show no interference effects. If all of the photons are not detected for one bunch, then the corresponding electron bunch 200 ly away would show the usual double-slit interference effects (say on a phosphorus screen). (Note that this does not require combining information from the photon-detector-side with the electron-double-slit side in order to get the interference effects. The interference effects would visibly show up as the electron blips populate the phosphorus screen, as is usual in a double-slit experiment when which-path information is not measured.)  In such a way the person at the photon detectors can send '1's and '0's depending on whether they measure the photons in a given bunch. Suppose they send 'SOS' in Morse code. This requires 9 bunches, and so this will take 900 milliseconds, which is less than 200 years. The point is that such an experiment would only work if you assume that the measurement of the photon really does collapse the wave function nonlocally. Proof of $\gcd(a,b)=ax+by\ $ [Bezout's identity] Show that $y_1$ and $y_2$ are not Linearly Independent Suppose that $y_1(x)$ and $y_2(x)$ are solutions of the differential equation $y''+py'+qy=0$ on $I$. How can I show that if $y_1$ and $y_2$ vanish at the same point then they are not linearly independent?   Here is my attempt to prove the problem. Since $y_1(x)$ and $y_2(x)$ are solutions of the differential equation $y''+py'+qy=0$ on $I$, it is enough for me to show that the Wronskian of $y_1$ and $y_2$ denoted by $W(y_1,y_2)$ is zero. Now since $y_1$ and $y_2$ vanish at the same point say $p$ we have $y_1(p)=0$ and also $y_2(p)=0$.   Solving for $W(y_1,y_2)(p)$ we have: $y_1(p)y_2'(p)-y_2(p)y_1'(p)=0$ since $y_1(p)=0$ and also $y_2(p)=0$.   Am I correct? Thanks I've found conflicting sources over who initiated the idea of Marvel's Multiverse having numbered universes.  Some say Alan Moore's Captain Britain was the first to use Earth-616, whereas others indicate it was fan-created from Fanzines: with Mark Gruenwald's Omniverse being the frontrunner.  Who is responsible for creating the universe designations? Is there any credible information on their development? Why are my quotation marks causing an “unexpected token” error with this command? Problem with glossary I am copying the very first piece of code from  in order to create a glossary. While I get no problem in the compilation I do not get the "glossary part" that appears in the example. I literally copy paste.  Also, I want to create a document that only consists of a glossary of various terms. That is to put everything in alphabetical order (with the possibility to include references as well). How could I possibly do this? I tried some itemize options with alphabetical order but does not look that good. I applied for a 90-day visa and got a long-term visit, single-entry tourist visa. The date given is 09-March-2015, and it's valid until 07-May-2015.  My agent says the 7th is the latest date I can travel to Dubai; once I enter I need to count 90 days. I entered on the 10th of March.    Is it true, or where can I get it checked?    Can I stay for another month, or do I need to leave before the 7th of May? If I take a loss when I sell my car, can I claim a capital loss deduction on my income tax return? What is an "AppImage"? How do I install it? I just read . It talks about downloading an AppImage.     Yes, Linux; the Linux packages is distributed as an .appimage for 32-bit and 64-bit distributions, and should run across all major Linux distributions without any issues. The team currently have no plan to provide a native .deb (or .rpm) installer.   What are AppImages? How do they differ from snaps? Setting environment variables on OS X What is the proper way to modify environment variables like PATH in OS&nbsp;X?  I've looked on Google a little bit and found three different files to edit:   /etc/paths ~/.profile ~/.tcshrc   I don't even have some of these files, and I'm pretty sure that .tcshrc is wrong, since OS&nbsp;X uses bash now. Where are these variables, especially PATH, defined?  I'm running  (Leopard). I have Ubuntu 16.04 with GNOME shell. I set ctrl+shift for the "Modifiers-only switch to next source" option.   This shortcut conflicts with apps hot-keys. I can't use ctrl+shift+i to open devtools in Chrome, it just switches the layout. In VS code IDE if I press shortcuts with ctrl+shift (for example ctrl+shift+f), shortcuts work but always switch a keyboard layout. When I used Windows this problem didn't exist.  Can I set the ctrl+shift shortcut in such a way that it causes a switch action only after the keys are released and only if this 2 keys were pressed (without additional keys)? Why is my Wi-Fi process using 3GB of memory? Some English words only differ in their vowels: crisscross, dillydally, riffraff, etc. Is there a name for them? Height and minimal number of generators of an ideal How can I determine the height and the least number of generators of the ideal $ I=(xz-y^2,x^3-yz,z^2-x^2y) \subset K[x,y,z] $?      I tried to calculate the dimension of the vector space $I/I\mathfrak m$ with $\mathfrak m=(x,y,z)$, but I'm not able to find it.  I think the height is $2$, because the affine variety should be a curve, and also I know that the ideal is prime, so I need a chain $0\subset \mathfrak p \subset I$. Maybe $(xz-y^2)?$ Is it prime? The difference between with or without intercept model in logistic regression I have a problem with my touchpad; I can't scroll down with 2 fingers and I don't know why. I have searched on Google about my problem and I've found some answers but none of them don't work for me.  One solution I found was to go in System Settings -&gt; Mouse &amp; Touchpad -&gt; Touchpad and check the Two-finger scrolling, but I don't have that option.    Another solution was to try to reinstall, which also didn't work. Yet another solution was to go in Ubuntu Software Center, type synaptic and install the Synaptic Package Manager but that didn't work, either.      What can I do to be able to scroll with two fingers? I don't like having the middle mouse button paste, because I often end up with uncompilable code in Eclipse. How can I turn this off (in all programs)? I'm running Fedora.