Assuming that you can't reach the internet nor reboot the machine, how can I recover from  chmod -x chmod   ?
Today I was told a tale by a Unix trainer where the root password got leaked to the students, and one of the fellas removed the execute permission from /usr/bin/chmod itself. How do you recover chmod in this case and make it executable again? Let's say getting it from an external source or recompiling it is not a preferable option, is there some smart hack that can recover this chmod itself?   Note that this happened a long time ago and I'm not looking for a solution for some current problem, just curious about what ways Unix provides us around such an issue.
Process substitution and pipe We know that continuous version of $\sum$ is $\int$, but, can there be a continuous version of $\Pi$? Uk tourist visa - duration of stay My mother is given a UK tourist visa for 2 years with a duration of stay as 180 days. It is a c type multiple entry visa. Is this 180 days is the total stay she can take or is it duration of stay per visit.  Thanks in advance for your reply. Take an FF body and a crop body, with similar MP rating - and the FF body will give a sharper image of the same object. At least, that seems to be the case - as here:    I assume a low ISO was used in both images.  Why does the FF body, with the same lens and almost the same MP, give an image that is so much sharper?   My best guess is that the diffraction / airy still play a role, and the larger pixels reduce effective overlap - thus increasing contrast/sharpness by displaying less of the neighboring diffraction, as below? I've checked  for acute:  an acute illness is one that has quickly become severe and dangerous Compare:CHRONIC  And for chronic:  lasting for a long time Compare:ACUTE  Can a disease be both &quot;acute&quot; and &quot;chronic&quot; simultaneously? For example it could be the case where a certain illness quickly becomes serious and have long term consequences Are there any &quot;obtuse illnesses&quot; ? How to determine a matching color code from a physical sample? I need to make a restaurant menu design that matches restaurant wallpapers. For some reason my client cannot get color codes used in wallpaper, but he provided me with a sample. (see below)    How can I get the correct color codes from the wallpaper? (someone mentioned that there are scanners for this purpose, but I could not find any information regarding that)  Let me know if this question should be in another site. Set Snap Mode with PyQGIS I am trying to set snap mode within QGIS plugin.  So far, I have tried:  QgsSnappingUtils().setSnapToMapMode(QgsSnappingUtils.SnapAdvanced)   and  QgsSnappingUtils().setSnapToMapMode(2)   without success.  QGIS Snapping options (Settings>>Snapping Options...) continue with:  Snapping mode = Current layer  Any hint? (Using v 2.14.0) This is a nice problem on series convergence that I recently stumbled upon. Given a non-negative sequence of real numbers $(a_n)$ such that $$\sum_{n=1}^\infty a_n &lt; \infty,$$ show that there exists a non-decreasing sequence of non-negative numbers $b_n$ such that $$b_n \to \infty \quad\text{ and } \quad \sum_{n=1}^\infty a_n b_n &lt; \infty.$$ In other words, for every convergent series with non-negative terms, there is another convergent series with "substantially larger" terms.  I have a solution (see below), but maybe someone else has a different, simpler, and/or more elegant solution. Checking via ArcPy if ArcMap is in edit session? I have a raster aerial photo.  I have county wide parcel data.  I want to clip/screen shot the raster at each individual parcel.  Think of this application - a post card with an image of your house --here is your house--  I want to have each parcel attribute to contain information + hyperlink of the aerial photo.  Any other solutions welcome, but this is the only method I could think of. Although I am unsure of how to achieve it efficiently.  Using ArcInfo 10. Traveling to the US with new passport, visa on the old one Install macOS Sierra on VirtualBox? I’m trying to install macOS Sierra on VirtualBox, but can’t seem to make it work. For reference, here are the steps I took.   Downloaded the Install macOS Sierra app from the App Store. Used the inbuilt media creation executable, CreateInstallMedia on a disk image. Created a new VM with the default settings for an OS X El Capitan, plus 128 VRAM. Since VirtualBox refused to accept the DMG, I tried splicing out the InstallESD. VirtualBox now accepted it, but wouldn’t boot. I tried to boot through rEFInd, but still no luck. I tried to patch it both ways (base system and ESD) with iesd. No luck. When booting to GParted LiveCD, it flat-out refused to discover any of the installer CDs.   How can I patch the installer to work with VirtualBox? I don’t want to use pre-patched versions of either the installer or an existing installation, as though to avoid piracy. I need to be able to compare some month names I have in an array.  It would be nice if there were some direct way like:  Month.toInt("January") &gt; Month.toInt("May")   My Google searching seems to suggest the only way is to write your own method, but this seems like a common enough problem that I would think it would have been already implemented in .Net, anyone done this before? How to install latest HPLIP on my Ubuntu to support my HP printer and/or scanner? Scheduling a Batch job at a particular time I have a Apex batch class which I would like to schedule at a particular date time. The date time is stored in a variable and changes dynamically. ex Datatime scduleDateTime = datetime.now() ; I want to schedule the apex batch file to run at this datetime variable value.  How can I do that using system.scheduleBatch()  I started with this but could'nt see how I can specify a datetime variable in here:  datetime d = datetime.now(); sampleapexbatch b = new sampleapexbatch(d); System.scheduleBatch(b,'Sample Job',XXXXXXXX)   Any help is appreciated! CSS alignment issues on close reasons with pending votes "Should" word in italics is shifted down in the vote-to-close popup when there is at least one pending close vote.  Just have a look at this:        Now without close votes:        So the issue occurs when there is a close vote on it. It doesn't look good.    Tested on Chrome 27.0.1453.116 m, Windows XP. And it looks fine on Firefox 21.0 and Opera 12.02 (Windows XP)  Here is an example of a slightly different but obviously related problem in Windows 7 SP1 and Firefox 21.0:    This seems to have something to do with how line-height and/or margin attributes are being interpreted.  Can this be fixed? Property of Entire Functions Suppose $f$ and $g$ are entire functions with $|f(z)|\leq|g(z)|$ for all $z$.  How can we show that $f=cg$ for some complex constant $c$?  Thanks for any help :) How do I kill entities at y=65? Potions can survive at y=65  One potion was thrown into the void, but instead of being killed, it just lingered there.  Any ideas to kill it? I can't just run /kill @e[type=!player,tag=test1]  (yes, the tag of the entity is indeed test1 ) ASP.NET MVC - Can't bind array to view model One divided by Infinity?