ls on home directory very slow A while ago, I accidentally created hundreds of thousands of files in my home directory which I subsequently deleted.  Since then however, running ls in my home directory has been extremely slow (taking tens of seconds to print). It has also been slow in other directories (as in taking 1s to print) and tab completion has been slow everywhere (also tens of seconds).  What might the problem be?  Edit: As suggested in the comments, the output of the      find ~/ -maxdepth 1 | wc   is 67 and the output of df -h is  /dev/sda2        74G  8.4G   62G  12% /  none            4.0K     0  4.0K   0% /sys/fs/cgroup  udev            3.9G   12K  3.9G   1% /dev  tmpfs           795M  1.1M  794M   1% /run  none            5.0M     0  5.0M   0% /run/lock  none            3.9G  4.9M  3.9G   1% /run/shm  none            100M   52K  100M   1% /run/user /dev/sda1       825G  408G  376G  53% /home AFS             8.6G     0  8.6G   0% /afs /dev/sdb2       1.9T  584G  1.3T  32% /media/sj1/ResearchData1  /dev/sdc1       932G  409G  524G  44% /media/sj1/ResearchData2
ls command very slow after deletion of thousand files on a directory I have a dir under /home/myuser dir which an application stores and deletes millions of temporary files. When I do ls on this dir (now it only has a hundred files only) it is too slow (actually I do not get any output for many minutes). After some google search and doing:  ls -dl ~/mydir/   I get this  drwxrwxrwx 2 myuser myuser 160108544 Oct 12 11:31 /home/myuser/mydir/   which basically means I have to re-index directory entries for this directory (if I understood correctly). How do I do force such a re-indexing on this dir?
Low rep users should be able to fix broken links At present a low rep user (under 2k) can only make an edit suggestion of more than 6 chars, however when someone has taken the time to find to correct link it is a real shame the correction can help other users!  So I think link fixing should be special cased somehow.  (Also the checkering of a changed link need to be better than other edits, so a page that showed what both the old a new links point to (in frames) could help with the approving processes.) postfix discard or change Message-ID header based on another header line I want to change the Message-ID header or better yet, discard it. I know everyone is going to ask "Why would you want to do that?" because I know it sounds weird to even write it.  Well I am developing a system that saves an incoming e-mail in EML format, changes it and sends it to the user, at some point the user can request to have the original EML sent to him/her. The issue is that when I re-send the EML it has the same Message-ID header which causes exchange servers to drop the re-send.  Of course I am hoping there is some option through postfix to do this, otherwise I will need to parse and change the EML but I rather not do that.  I tried to do this with "header_checks" and it works BUT I need to be able to do this conditionally, meaning only on a specific occasion, which I can identify by looking at the other headers, I want to remove the Message-ID. Is it okay to have a multi-language deck? I want to buy a few booster pack from a local shop that only gets them in French. Is it generally acceptable to show up to a tournament with cards in different languages? I'm one of those exceptions that deviates from the norm: I run CyanogenMod without any Google apps.   Is it possible to download the Stack Exchange Android app .apk directly? Travelling with two different passports I was just wondering if you have two passports (a Chinese one and an Australian one), and you booked your airline ticket with the Chinese one, will you have to show both of your passports or just one?  The thing is, on my Chinese passport, it has my birth name, but then when I became an Australian citizen, I legally removed my Chinese name and replaced it with my English name. So I don't know whether I should just show the passport officials the one that I booked the airline ticket with. setuid root does not work Objective : Run a program as root (C++ binary). The same as :   And :   ./a.out output:  E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root? psurana  //output for "whoami" Look below for the code.   ls -l output:  -rwsrwxr-x 1 root    root    46136 Jun  7 20:13 a.out  The Code :   #include &lt;string&gt; #include &lt;stdlib.h&gt; int main(int argc, char *argv[]){         std::string input = "apt-get install " + std::string(argv[1]);         system(input.c_str());         system("whoami");         return 0; }   Details: : compiled the program and then did chown root:root a.out &amp;&amp; chmod u+s a.out. Please look above for ls -l output.  I still do not get the root privileges and the output for system("whoami") in the code is my own username on the machine.  Reading the two linked questions did not yield me anywhere. :(. both the creator and the owner of the file are root. The setuid bit is set, so it should work. The filesystem is not external either, it is my own machine. How can I make this work? Programmatically Create X509 Certificate using OpenSSL The selection toggle arrows in the Outliner disappeared. Is there some preference in the settings that has to be turned on? Is there a way to solve this integral?  $$\int \frac{dx}{\sqrt{-ax^2 + bx +c}}, \;\;\;\;\; \forall\; a,b,c \in (0,+\infty) \;in\;R$$  I have tried it by changing of variable and by parts, but no result. I don't know what else to do.  Thanks in advance. Drop Tables with Bigger size We have a mysql database with a size of 2 TB, in which we have for to five big tables ranging from 110GB to 350GB. When we try to drop these tables the mysql goes to the defunct mode and hangs in that state for a long time. Is there a solution to drop these tables without mysql hanging. We have a machine which has a memory of 122GB and swap of 60 GB. We use an InnoDB Engine Hope the information suffices kindly help us with this issue Multivariable limit proof: $\lim\limits_{(x,y)\rightarrow (0,0)}\frac{\left|x\right|^a\left|y\right|^b}{\left|x\right|^c + \left|y\right|^d} = 0$ Please add documentation about the redaction tool to the moderator help Why does the volume of the unit sphere go to zero? The volume of a $d$ dimensional hypersphere of radius $r$ is given by:  $$V(r,d)=\frac{(\pi r^2)^{d/2}}{\Gamma\left(\frac{d}{2}+1\right)}$$  What intrigues me about this, is that $V\to 0$ as $d\to\infty$ for any fixed $r$.  How can this be?  For fixed $r$, I would have thought adding a dimension would make the volume bigger, but apparently it does not.  Anyone got a good explanation? How to make an image center (vertically & horizontally) inside a bigger div Note: this is intended to be a canonical question about summoning sickness.  "Summoning sickness", broadly, is the rule that stops you from attacking or paying {T} costs with a creature that you just played. But how exactly does it work? How does it interact with other rules and effects?  For example, if I'm trying to figure out how a creature is affected:   Does the status matter (tapped/untapped, face down/face up, etc.)? What if it came into play, but I didn't cast it? What if it's a token? What if it was on the battlefield when my turn started, but it wasn't a creature? What if it stops being a creature? What if it's a creature and also another card type? What if it's a double-faced card that just transformed? What if it changes control? What if it's a copy of another creature? Which of the creature's activated abilities can I use? Are any of its other abilities affected? Can I tap the creature to pay a cost that is not a {T} cost?   (These examples are primarily taken from questions about summoning sickness that have already been asked on the site) Recovering accidentally deleted files I accidentally deleted a file from my laptop. I'm using Fedora. Is it possible to recover the file? While trying to create a custom business rule using Apex I got the error:  INVALID_ID_FIELD, SaveAsActivity is not allowed with whatId that is not supported as a task whatId.  ...and found out that it was caused by the method setSaveAsActivity on my code, that was like:  msg.setSaveAsActivity(true); // "msg" is a SingleEmailMessage   What am I doing wrong here? doing comparison if else in JasperReports Calling C/C++ from Python? Let $R$ be a sub-ring of a ring $S$. Let $f,g$ be non-zero polynomials in $R[x]$ and assume that the leading coefficient of $f$ is a unit in $R$. If $f$ divides $g$ in $S[x]$, show that $f$ divides $g$ in $R[x]$.   Thoughts: If $f$ divides $g$ in $S[x]$, then  $g(x) = f(x)q(x)$ for some $q(x)$ in $S[x]$. From here I'm not sure what the question is asking. Do I have to show that $q(x)$ is an element of $R[x]$ ? Insights appreciated.