Are evals in Javascript really a security risk, when the code is available anyway.
Exploiting JavaScript's eval() method
A good title helps your question get the attention it deserves.  What goes into a good title? Clipping raster with vector boundaries using QGIS In QGIS I would like to clip a raster precipitation layer using an admin boundary layer that is vector data. However the Geoprocessing tools seem to be usable only for vector data. How can I clip this precipitation layer? Prove that sequence $ x_{(n+1)}= \frac {a}{1+x_n}$ is convergent to positive root of $x^2+x-a=0,$where $a >0$ and $x_1 >0$ Prove that sequence $$ x_{(n+1)}= \frac {a}{1+x_n}$$ is convergent to positive root of $x^2+x-a=0,$where $a &gt;0$ and $x_1 &gt;0$  we have $$x_{(n+2)}-x_n=\frac{-a(x_{(n+1)}-x_{(n-1)})}{(1+x_{(n-1)})(1+x_{(n+1)})}$$  Hence from this we see behaviour of even terms subsequence and odd terms subsequence  is opposite. how to proceed from there. any hint please SQL - Order by with alphanumeric characters Adjoint matrix eigenvalues and eigenvectors I just wanted to make sure that the following statement is true:  Let $A$ be a normal matrix with eigenvalues $\lambda_1,...,\lambda_n$ and eigenvectors $v_1,...,v_n$. Then $A^*$ has the same eigenvectors with eigenvalues $\bar{\lambda_1},..,\bar{\lambda_n}$, correct? The script I use is actually returning this output:  (source /Thetra/Commun/env_ora.sh &gt;/dev/null; sh aclenv/arun)  geIlgif0t1 -DVORACLE geIlgif0t1 prg_25900: ACOMP=X geAhadlAd1 -DVORACLE geAhadlAd1 prg_25948: ACOMP=A syCcgge0t1 -DVORACLE syCcgge0t1 prg_26023: ACOMP=S2 syVcalq0t1 -DVORACLE syVcalq0t1 prg_26071: ACOMP=Y syVvali0t1 -DVORACLE syVvali0t1 prg_26119: ACOMP=Y syAedit0t1 -DVORACLE syAedit0t1 prg_26167: (1312) DBMS WARNING: Column not found in table. (-11238)   RETURN (-6)     END  END     END     IF cm_para_f2('VDEF','abQtip_0n1','unicite',syAedit0t1:$v_unicite)&lt;&gt;0      OR null_convert$(syAedit0t1:$v_unicite,'R') &lt;&gt; 'F' THEN SET syAedit0t1:$v_unicite TO 'R'     SET $v_tips_mrgl TO 'S'     SET $v_rfbt_iban, $v_rfbt_intitule, $v_orga_creancier, $v_orga_tip_adr1, $v_orga_tip_adr2,         $v_orga_tip_adr3, $v_code_docu, $v_tips_centre, $v_code_etab, $v_orga_tip_emetteur,  $v_orga_emetteur, $v_rfbt_compte, $v_orga_banque, $v_rfbt_emetteur TO     SELECT rfbt_iban, rfbt_intitule, orga_creancier, orga_tip_adr1, orga_tip_adr2, orga_tip_adr3 ACOMP=N syAvali0t1 -DVORACLE syAvali0t1 prg_26215: (2751) DBMS WARNING: Column not found in table. (-11238)  + to_string_using$(str_to_val$(substr$(clip_str$(to_string$($f_imme_no)),1,4)),'&amp;&amp;&amp;&amp;')         + to_string_using$(str_to_val$(substr$(clip_str$(to_string$($f_sepa_propriete_no)),1,5)),'&amp;&amp;&amp;&amp;&amp;')     IF syAvali0t1:$v_unicite ='R' THEN  SET $v_sepa_rum3 TO $v_sepa_rum3 + substr$(to_string_using$(syAvali0t1:$v_ordr_direct,'&amp;&amp;&amp;&amp;&amp;&amp;&amp;&amp;&amp;'),7,9)     ELSE ACOMP=N syAcalc0t1 -DVORACLE syAcalc0t1 prg_26263: ACOMP=N syAcalc0t2 -DVORACLE syAcalc0t2 prg_26311: ACOMP=N syAcalc0t3 -DVORACLE syAcalc0t3 prg_26359: ACOMP=N   To check for errors I use the following command:  (source env_ora.sh &gt;/dev/null; sh aclenv/arun) | egrep '^ACOMP=$'   Output:  (1312) DBMS WARNING: Column not found in table. (-11238)   RETURN (-6)     END  END     END     IF cm_para_f2('VDEF','abQtip_0n1','unicite',syAedit0t1:$v_unicite)&lt;&gt;0      OR null_convert$(syAedit0t1:$v_unicite,'R') &lt;&gt; 'F' THEN SET syAedit0t1:$v_unicite TO 'R'     SET $v_tips_mrgl TO 'S'     SET $v_rfbt_iban, $v_rfbt_intitule, $v_orga_creancier, $v_orga_tip_adr1, $v_orga_tip_adr2,         $v_orga_tip_adr3, $v_code_docu, $v_tips_centre, $v_code_etab, $v_orga_tip_emetteur,  $v_orga_emetteur, $v_rfbt_compte, $v_orga_banque, $v_rfbt_emetteur TO     SELECT rfbt_iban, rfbt_intitule, orga_creancier, orga_tip_adr1, orga_tip_adr2, orga_tip_adr3 (2751) DBMS WARNING: Column not found in table. (-11238)  + to_string_using$(str_to_val$(substr$(clip_str$(to_string$($f_imme_no)),1,4)),'&amp;&amp;&amp;&amp;')         + to_string_using$(str_to_val$(substr$(clip_str$(to_string$($f_sepa_propriete_no)),1,5)),'&amp;&amp;&amp;&amp;&amp;')     IF syAvali0t1:$v_unicite ='R' THEN  SET $v_sepa_rum3 TO $v_sepa_rum3 + substr$(to_string_using$(syAvali0t1:$v_ordr_direct,'&amp;&amp;&amp;&amp;&amp;&amp;&amp;&amp;&amp;'),7,9)     ELSE   We can see that grep is returning non matching lines.  When I redirect the stderr to stdout with this command:  (source /Thetra/Commun/env_ora.sh &gt;/dev/null; sh /Thetra/Oracle/transfert/P2016.H.1/aclenv/arun) 2&gt;&amp;1 | egrep '^ACOMP=$'   As expected, the output is void.  Why grep is returning non matching lines when stderr is not redirected ? Why are map tiles being repeated? Using MapServer and Openlayers Problem I have: map tiles from my layer are being repeated.  Shapefile is projection 3059. I have specified 3059 is in the mapfile and also when creating map object.  I know OpenLayers.Layer.WMS is recommended, but when I use it I only see empty map. When I use OpenLayers.Layer.MapServer, map is displayed (and tiles are repeated), so I'm using that for now.  My layer (EPSG:3059) looks like this    Versions: Openlayers 2.13.1 MapServer 6.0.3  WMS Server mapfile:  MAP     NAME country_map     STATUS ON     SIZE 800 500     EXTENT 313187.4 146161.56 766469.92 470367.64     UNITS METERS     SHAPEPATH "shapefiles"     IMAGECOLOR 155 155 155      WEB         TEMPLATE "template.html"         IMAGEPATH "C:/MS4W/ms4w/apache/htdocs/gis/output/"         IMAGEURL "/gis/output/"          METADATA             "wms_title"             "MapServer + Openlayers"             "wms_onlineresource"    "http://localhost:1025/cgi-bin/mapserv.exe?map=C:\MS4W\ms4w\Apache\htdocs\gis\mapfile2.map"             "wms_enable_request"    "*"             "wms_srs"               "EPSG:3059"         END     END      PROJECTION         "init=epsg:3059"     END  # example layer     LAYER     METADATA         "wms_title"             "lat_rob_region"     END     NAME "lat_rob_region"     DATA lat_rob_region     STATUS ON     TYPE POLYGON         CLASS             NAME "lat_rob_region"             STYLE                 COLOR 0 255 0             END         END     END END   Javascript:  var lon = 25; var lat = 57; var zoom = 5; var map, layer1;  function init() {     map = new OpenLayers.Map( 'map',{displayProjection: new OpenLayers.Projection("EPSG:3059")} );      layer1 = new OpenLayers.Layer.MapServer( "Country map",              "http://localhost:1025/cgi-bin/mapserv.exe?map=C:/MS4W/ms4w/Apache/htdocs/gis/mapfile2.map", {layers: 'lat_rob_region'},             {gutter: 15},{srs: 'EPSG:3059'});     map.addLayer(layer1);      map.setCenter(new OpenLayers.LonLat(lon, lat), zoom);     map.addControl( new OpenLayers.Control.LayerSwitcher() ); } How should I install HPLIP binary/proprietary plugin/driver for my HP printer or printer+scanner? Let's assume that one has some modern HP printer and/or scanner which is  supported by HPLIP package from official repository. Or supported by newer version of HPLIP package (see  about installation).  From official documentation () it is known that device needs proprietary/binary driver or plugin.  How should one install such plugin? note: This is a question about relativistic effects. I've included some detail about the spacecraft and its orbit for background, but the question is about relativistic effects and their observability.     When the Parker Solar Probe passes within 8.5 solar radii of the Sun, it will be moving really fast.  A perihelion and aphelion of about 6.6 and 109 million kilometers suggests a semi-major axis of 57.8 million kilometers. The standard gravitational parameter for the Sun is:  $$GM_{Sun} \ = 1.327\times 10^{20} m^3/s^2$$  So using the :  $$v^2 \ = \ GM_{Sun}\left(\frac{2}{r}-\frac{1}{a}\right)$$  the orbital velocity at perihelion will be about 195,000 m/s, or about 25 times faster than a satellite in LEO. This is close to one part per thousand of the speed of light! I think this will be a new record for a spacecraft velocity relative to the solar system.  Depth of a gravitational potential well for an object of mass $m$ is approximately given by:  $$u_G \ = \ -GM_{Sun}\frac{1}{r}$$  At 6.6 million kilometers the spacecraft will be 23 times deeper in the Sun's gravitational well than it would be at 1 AU.  Will there be any particularly unique relativistic effects detectable for the Parker Solar Probe during it's close flyby of the Sun?  Just for example, during one close flyby, how much time will its on-board clock gain or lose compared to some convenient standard solar system timescale? I know there are several different choices, "GPS time" might be one but I don't want to arbitrarily choose an inconvenient one.     above: Parker Solar Probe cropped, from .    above: screen shot from NASA's      note: the link seems to be dead now, but there is plenty of related information available at     above: Illustration of the Parker Solar Probe's orbit, from . I have a header file  x.h which is included by more than one *.c source files. This header file has some structure variables defined.  I have put multiple inclusion prevention guard at the beginning of the header file as:  #ifndef X_H #define X_H ... .. //header file declarations and definitons.   #endif//X_H   On building I get linker errors related to multiple definitions. I understand the problem.   Won't a multiple inclusion prevention guard at the top of header file as I have, prevent multiple inclusions of the header file x.h and thereby avoid multiple definitions of the variables that are there in x.h? #pragma once does not work on this particular compiler, so what is the solution?  Someone had posted  answer to a similar question. It doesn't seem to work for me. How does this solution work? I have a client whose workforce is comprised entirely of remote employees using a mix of Apple and Windows 7 PCs/laptops.   The users don't authenticate against a domain at the moment, but the organization would like to move in that direction for several reasons. These are company-owned machines, and the firm seeks to have some control over account deactivation, group policy and some light data-loss prevention (disable remote media, USB, etc.) They are concerned that requiring VPN authentication in order to access AD would be cumbersome, especially at the intersection of a terminated employee and cached credentials on a remote machine.  Most services in the organization are Google-based (mail, file, chat, etc.) so the only domain services are DNS and the auth for their Cisco ASA VPN.  The customer would like to understand why it is not acceptable to expose their domain controllers to the public. In addition, what is a more acceptable domain structure for a distributed remote workforce?  Edit:   is in use for a handful of Mac clients. Reference request: convergence for periodic Markov chains Consider an irreducible but possibly periodic Markov chain on a finite state space with transition matrix $P$. We know there exists a unique stationary distribution $\pi$. If the Markov chain were aperiodic, we would have $P^n_{ij} \to \pi(j)$ as $n \to \infty$. This fails if the chain is periodic, but we have convergence of the Cesaro averages: $$\frac{1}{n}\sum_{k=1}^n P^k_{ij} \to \pi(j) \text{ as } n \to \infty.$$ Can anyone point me to a reference that states this fact? Every reference I've seen only considers convergence for aperiodic chains, or "fixes" periodicity by considering a lazy version of the chain. Alternatively, is there a simple way to obtain this result using the result for aperiodic chains? Current situation: I'm required to cite "normative" documents (read: standards and manuals) separately from articles and books etc. Using biblatex and biber with the numeric style I'm doing that by issuing multiple printbibliography commands like so:  \usepackage[style=numeric,backend=biber,bibencoding=utf8]{biblatex} %... lots of stuff \printbibliography[type=standard,title=Standards \&amp; Manuals] \vskip\baselineskip \printbibliography[type=manual,heading=none] \printbibliography[nottype=standard,nottype=manual]   which gives a heading Standards &amp; Manuals, prints a list of manuals, leaves a bit of space then the list of standards and finally, under a new heading Bibliography gives books and articles etc. Thus far everything is fine, enter:  The Problem: I'm using the shorthand field in my database for the standards and manuals which works perfect as far as output within the text is concerned and sets the shorthand as the label in the bibliography and prints the details to the right of it - problem is: my shorthands are considerably longer than the labels generated by the numeric style, but even though they're in three different \printbibliography commands, everything gets indented to the maximum width of the label, making the part for books and articles look quite ridiculous.  The following shows the problem with only two separate \printbibliography (and an obviously exaggeratedly long shorthand):   Now  what I would obviously want is for each of the \printbibliography commands to only use the indentation actually necessary to accommodate the largest label appearing within, i.e. rendering the Manuals section as above, but the Bibliography section like follows:   Can anyone help me to achieve this? Or give me some pointer where to look?  The above was produced with the following MWE on an up-to-date TeXLive 2014:  \documentclass[10pt,british]{scrbook}  \usepackage{babel} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage{lmodern}  \usepackage{filecontents} \begin{filecontents*}{\jobname.bib} @manual{HowTo,     title = {How to Make the World Go Round},     shorthand = {HowToMakeTheWorlGoRound},     publisher = {The Publisher},     year = {2000} }  @article{Article,     author = {Author, A. and Buthor, B.},     journal = {Journal Title},     pages = {113--126},     title = {The Article},     volume = {65},     year = {1900} } \end{filecontents*}  \usepackage[style=numeric,backend=biber,bibencoding=utf8]{biblatex} \addbibresource{\jobname.bib}  \usepackage[hidelinks]{hyperref}  \begin{document} \let\cleardoublepage\relax \chapter{The Document} Nothing to see here, but we refer to the \parencite{HowTo} based on a principle discovered by \textcite{Article}.  \printbibliography[type=manual,title=Manuals] \printbibliography[nottype=manual] \end{document} grep a file, but show several surrounding lines? A word to describe "work that is ready to be done" Increase close vote weight for gold tag badge holders In order to increase the efficiency with which poor quality questions are closed, it could make sense to have weighted close votes for a small subset of qualified users.   A very good way to measure the qualified users would be to leverage the tag badges. However, it needs to be rationally limited to a set of users that are knowledgeable with the subject. A very good way to measure the top users in a tag would be to look at those who have a gold badge in the tag.  If two users who have a gold tag badge pertinent to a question issue a close vote, the question should probably be closed (or probably will be very soon under the current system). I think it would make sense to allow users with a gold tag badge to have a 3x weight for close votes in those tags.  Please keep in mind, this isn't suggesting full moderator one click closure. It only adds weight to the vote. A single user could not do it on their own. These singular users cast close votes all the time, so that aspect would not change. Some will vote to close, some wont, but the ones who do should have a stronger weight to their vote. Even with 3x it will require 2 of said votes to accomplish, or still 2 other users (meaning 3 agreed it should be closed - which is the same amount of high rep users it takes to delete a question and that has a much greater impact than closure).  tldr;  Allow gold tag badge users to have a weighted close vote in their tag I tried to obtain the size of a directory (containing directories and sub directories) by using the ls command with option l. It seems to work for files (ls -l file name), but if I try to get the size of a directory (for instance, ls -l /home), I get only 4096 bytes, although altogether it is much bigger. Does more reflective aluminum foil make a room cooler compared to less reflective foil? Aluminum foil is said to be not absorbing light at all. It reflects light. So, does it mean that a more shiny aluminum foil will reflect more light and thus make the room more cooler as compared to less shiny foil?  If yes, then where does unreflected light go in case of less shiny aluminum foil?  Does less shiny and more shiny actually make a difference? Why?  In order to keep whole room cool will it help if I stick the foil to the outside of wooden door (exposed to the sunlight) too? How do I convert a video to GIF using ffmpeg, with reasonable quality? I'm converting a video to GIF file with ffmpeg:  ffmpeg -i input.flv -ss 00:00:00.000 -pix_fmt rgb24 -r 10 -s 320x240 -t 00:00:10.000 output.gif   It works great, but output gif file has a very low quality.  Any ideas how can I improve quality of converted gif? Is it possible to build a single mysql query (without variables) to remove all records from the table, except latest N (sorted by id desc)?  Something like this, only it doesn't work :)  delete from table order by id ASC limit ((select count(*) from table ) - N)   Thanks.