ROC vs. Accuracy
Advantages of ROC curves
Accessing laptop's hard drive when OS won't boot How do you make Ubuntu accept files sent over bluetooth Is there a detailed user's documentation for KDE Plasma 5? nginx location match issue auth_basic I have this configuration :  location / {     root /etc/nginx/euchet; }  location /app/ {     proxy_pass http://172.16.184.2:8080;     proxy_redirect off;     proxy_set_header Host $host;     proxy_set_header X-Real-IP $remote_addr;     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;     proxy_set_header REMOTE_ADDR $remote_addr; }   And I need to add another location with auth_basic enabled only for the request: /app/f?p=3000  I tried with rexexp:     location ~ \/appt\/f\?p=3000 {             auth_basic "Hello! Enter password";             auth_basic_user_file /etc/nginx/euchet.htpasswd;              proxy_pass http://172.16.184.2:8080;             proxy_redirect off;              proxy_set_header Host $host;             proxy_set_header X-Real-IP $remote_addr;             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;             proxy_set_header REMOTE_ADDR $remote_addr;     }   Nginx use previous location /app/.  I tried another way:  location ~* /euchet/f {      if ($arg_p = "4550") {         return 403;     }      error_page 403 = @hidden; }     location @hidden {             auth_basic "Hello! Enter password";             auth_basic_user_file /etc/nginx/euchet.htpasswd;              proxy_pass http://172.16.184.2:8080;             proxy_redirect off;              proxy_set_header Host $host;             proxy_set_header X-Real-IP $remote_addr;             proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;             proxy_set_header REMOTE_ADDR $remote_addr; }   And I get 403 error on f?p=3000, and 404 errors on f?p=&lt;another_number&gt;  How can I fix this problem? Why can't cloaked vessels shoot? Lag compensation with networked 2D games I want to make a 2D game that is basically a physics driven sandbox / activity game. There is something I really do not understand though. From research, it seems like updates from the server should only be about every 100ms. I can see how this works for a player since they can just concurrently simulate physics and do lag compensation through interpolation.  What I do not understand is how this works for updates from other players. If clients only get notified of player positions every 100ms, I do not see how that works because a lot can happen in 100ms. The player could have changed direction twice or so in that time. I was wondering if anyone would have some insight on this issue.  Basically how does this work for shooting and stuff like that?  Thanks Does a run scored on a tag out on a forced runner? The situation:   Runners at third and first, ball is hit to the second basemen, 2nd basemen goes to tag the runner out. Runner stops, runner on third scores and then 2nd basement tags the runner, does not step on base.Does the run count? Test if there are files matching a pattern in order to execute a script I am trying to write an if statement to test whether there are any files matching a certain pattern. If there is a text file in a directory it should run a given script.  My code currently:  if [ -f /*.txt ]; then ./script fi   Please give some ideas; I only want to run the script if there is a .txt in the directory. Can you have a class in a struct? Why is the minimum size of a generating set for a finite group at most $\log_2 n$? It seems to be known that the minimum size of a generating set for a finite group of order $n$ is at most $\log_2 n$. Can someone explain why this is true?  Edit: noted that the logarithm is base 2, and $n$ represents the order of the group. How to align a  to the middle (horizontally/width) of the page Polar form to cartesian Let $\Gamma$ be a circle that passes through the origin. Show that we can find real numbers $s$ and $t$ such that $\Gamma$ is the graph of $r = 2s \cos (\theta + t).$  I know this has to be converted to a cartesian equation, but how do I do this, and what do I do after?  Thanks Can a word be contracted twice (e.g. "I'ven't")? How are Wolverine's claws still in his body? Everyone knows that Wolverine's adamantium claws are super-sharp — sharper than even a razor — and virtually indestructible. What puzzled me the first time I saw Wolverine is: how do the claws stay in his body?  As it is shown, Wolverine's flesh and skin are human in strength, but the healing factor makes it superhumanly durable and strong. Still, when Wolverine slashes something, or someone, extremely hard, dense, or thick (as he has to use great amount of force), the claws don't tear through his hand and leave his hand through the opposite side of the palm (because of the action having equal and opposite reaction). Why is quantum entanglement considered to be an active link between particles? I have an alias that I would like to use both as a regular user and as root, via sudo. Specifically, it is this:  alias rm=trash   This works fine as a normal user, and it works fine when I use sudo -i to get a root shell prompt, but if I use sudo rm, the alias does not apply. So where do I need to put my alias so that it works in one-off sudo commands? How to set up a root cron job properly I tried to set up a root cron job to run a Bash script as root, to run at minute 7,37, every hour, every day of month, every month. This script is located in /usr/bin and named tunlrupdate.sh. It updates the DNS of Tunlr.  $ ls -l /usr/bin/tunlrupdate.sh  -rwxr-xr-x 1 root root 2133 Sep 24 15:42 /usr/bin/tunlrupdate.sh   This Bash script is available .  When invoked the script writes what's happening in a log located in /var/log/tunlr.log  To add this root cron job I used the standard for root's crontab  sudo crontab -e   And inserted these 2 lines at the end. I expect cron to run the script as root.  # check for updated Tunlr DNS every 30 minutes at the hour + 7 mn and hour + 37 mn 07,37 * * * * root /usr/bin/tunlrupdate.sh   A later command sudo crontab -l confirmed that the cron job has been inserted.  I did reboot Ubuntu and was checking in the log file if the cron job was launched properly. However there is nothing in the logfile /var/log/tunlr.log meaning the job was never successfully launched.  I did check that if I run the script from the command line  sudo /usr/bin/tunlrupdate.sh   then the logfile is updated accordingly.  Why is this cron job not running as planned in my system?  UPDATE 1 : All the proposed solutions so far do not work. I thank Olli for a CLI to list the system log sudo grep CRON /var/log/syslog. However I did get a CRON error  CRON[13092]: (root) CMD (  [ -x /usr/lib/php5/maxlifetime ] &amp;&amp; [ -d /var/lib/php5 ] &amp;&amp; find /var/lib/php5/ -depth -mindepth 1 -maxdepth 1 -type f -cmin +$(/usr/lib/php /maxlifetime) ! -execdir fuser -s {} 2&gt;/dev/null \; -delete)   with the suggested PATH= insertion &amp; use of absolute path from root for functions in the script or without this suggested solutions here. I still get this error.  After some searching I pinpointed the error in the file /usr/lib/php5/maxlifetime as is explained : Change #!/bin/sh -e --&gt; #!/bin/sh -x  Then listing the CRON error log in my system  sudo grep CRON /var/log/syslog Feb 11 18:07:01 Marius-PC CRON[14067]: (root) CMD (root /usr/bin/tunlrupdate.sh) Feb 11 18:07:01 Marius-PC CRON[14066]: (root) MAIL (mailed 1 byte of output; but got status 0x00ff, #012)   I still don't get the bash script executing. This time no error is shown in the log. To get assurance this was not the content of the script I reduced the script to the following 3 lines:  #!/bin/bash LOGFILE=/var/log/tunlr.log echo $LOGFILE &gt;&gt; $LOGFILE   I still don't get the cron job through. Nothing is written in the log file. So even may be an empty script will not run in cron ? I don't get it. I am know trying a script reduced to these 2 lines:  #!/bin/bash exit 0   And still the same error log. The cron script does not go through ... Why doesn't Normal[] work on GeometricTransformation? Closure of the set of degree $n$ polynomials with $n$ real roots A very beautiful (but maybe classic) exercise:   Consider the set $\Omega_n$ of polynomials of degree $n$ with real coefficients and $n$ distinct real roots.   What is the closure of $\Omega_n$ in $R_n[x]$?  ($R_n[x]$ denotes the set of polynomials with real coefficients of degree at most $n$)    The answer is the set of polynomials in $R_n[x]$ all of whose roots are real, plus the constant polynomials. Showing that this set is contained in the closure is not too hard, however the reverse implication is more difficult and I'm wondering what is the most elementary method to prove it (without talking about holomorphic functions for example). Every time I try to install "WINE" VIA the Software Center on Ubuntu 12.10, I get this error:  The following packages have unmet dependencies:  wine1.4: PreDepends: dpkg (&gt;= 1.15.7.2~) but 1.16.7ubuntu6 is to be installed          Depends: libc6 (&gt;= 2.14) but 2.15-0ubuntu20 is to be installed          Depends: wine1.4-amd64 (= 1.4.1-0ubuntu1) but 1.4.1-0ubuntu1 is to be installed          Depends: wine1.4-i386 (= 1.4.1-0ubuntu1) but it is not going to be installed   When I try installing it VIA the terminal, this is what I get:  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  wine1.4 : Depends: wine1.4-i386 (= 1.4.1-0ubuntu1) but it is not installable            Recommends: gnome-exe-thumbnailer but it is not going to be installed or                        kde-runtime but it is not going to be installed            Recommends: ttf-droid            Recommends: ttf-mscorefonts-installer but it is not going to be installed            Recommends: ttf-umefont but it is not going to be installed            Recommends: ttf-unfonts-core but it is not going to be installed            Recommends: winbind but it is not going to be installed            Recommends: winetricks but it is not going to be installed E: Unable to correct problems, you have held broken packages.   how do I fix this?