I am compiling a pdf in Overleaf but even if there is a minor change, the pdf will be compiled from scratch and that will take a while for a large document. How to avoid this? Is there an option to specify a setting so that only a part that was modified will be changed in the pdf?
I see that there a number of questions (, , , , ) on best practices, none of them answer the issue I am going to talk about.  We all need to prepare large documents (or slides) from time-to-time. And once you have reached a certain number of pages, you find that compiling the whole document takes a substantial time, which you need to do to check that the part you have written is error free, specially if it contains a number of images.   To circumvent the situation, I have used the following practices over years to keep compile time at minimum.   Divide the document in to many chapters: The chapters are put in separate files. Only the one I am working one is uncommented.  \documentclass{book}  \begin{document}  %\input {chapterone.tex} \input {chaptertwo.tex} %\input {chapterthree.tex} %\input {chapterfour.tex}  \end{document}    The above technique can also be used for \include.   Keep a preamble replica of the main file in a temporary file (build file): I use this technique when I am preparing a presentation with many slides, say a hundred. Prepare a main file, copy it to another build file. Delete everything between  \begin{document} and \end{document} in the build file. Prepare a slide (or a group of slides) in the build file. Cut and paste the contents between \begin{document} and \end{document} in the build file to relevant location in the main file only when satisfied with the output (image locations, overfull boxes etc.)     We can hear your inputs about the best practices you practice when a you are preparing a document or presentation from scratch.    Now, I have failed to find a good answer in the case when you have finished the whole document or presentation and now you need tweaking the small things, may be edit a text here, add an image there. What will be your best practice?  Perhaps, again keeping only one chapter uncommented will be usable here. But what about large presentations? May be adding a \end{document} just after the point-of-change will be beneficial, but only if you can put that before midpoint of the file.  Commenting a part of the file will also work, but that is error-prone, at least for me.
Is it (theoretically) physically possible to project an image into thin air? Named Credentials - Merge Fields not Resolving Can somebody please explain when parent process receives the exit status of a dead child process via wait, who actually reallocates the memory of the child process and removes it from the process table? How to make program autostart only in GNOME I use both GNOME and KDE SC. In GNOME, I use Docky but I do not use it with KDE. So, I would like Docky to start up only when I login into GNOME not KDE. In KDE, there is an option to make a program autostart only in KDE. But I cannot find any such option in GNOME.    How can I do this?    Thanks in advance. Apex compile error : variable does not exist I'm having issues with creating a pretty simple test Utility Class. I want to create two records: an account and a related child contact. The error I see in the developer console is:     Variable does not exist: a.ID   My code, based on the Salesforce Apex Workbook, is as follows. I've played around with various things, but it's not working. Where am I going wrong? Thanks in advance.  @isTest public class AccountSaveTestSuite {      public static Account createOneAccount(){           Account testAccount = createAcct('ABC Computing inc.');              Contact testContact = createContact();          return testAccount;             }      // Helper methods //     //        private static Account createAcct(string accountName) {          Account a = new Account(             Name=accountName);         insert a;         return a;     }      private static Contact createContact(){         Contact c = new Contact (             FirstName = 'Jane'              , LastName = 'Smith'             , Account = a.ID); // *** Error is here ***         insert c;         return c;      }  } Boliviana de Aviacion (BOA) tariff codes I am trying to book one-way tickets on BOA on Jan 13 2015 from La Paz (LBP) to Buenos Aires (EZE) from their website.  Their website asks me to make a choice between 7(!) different tariff codes - they are SSEEOB, QEEOB, TMEEOB, VEEOB, HEEOB, BEEOB, YOW. The prices are different for every tariff, but other than that I cannot see any obvious difference and there is no explanation available. Also I am unable to find anything useful on their website  Could anyone from Bolivia or familiar with BOA explain what is going on there and what choice am I supposed to make? Is there a ZIP code I can enter when paying-at-the-pump in the USA with a foreign credit card? In the USA, many  fuel dispensers that accept credit cards require a  that corresponds to the billing address of the credit card.  In Canada, for instance, we have , so it's not obvious what you're supposed to type in since the gas dispensers have only numeric keypads.  Entering '00000' or '90210' seems to always result in failed authorization.  Is there a zip code that works for credit cards with foreign billing addresses? 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I currently have a valid multiple entry Schengen visa that expires on Feb 10th (issued by the Spanish consulate). I need to visit the Czech Republic from Feb 9th to Feb 15th. For this, I am getting a visa starting Feb 11th from the Czech consulate as I was advised that I cannot have two simultaneous visas.   Is it possible for me to enter Czech republic on the current visa on Feb 9th, and stay past its expiry up to Feb 15th using the new visa without leaving the Czech Republic? Will there be any likely problem either while entering or exiting Schengen zone (I am entering Schengen in Frankfurt)? One whose solution never makes me happy is the following: $$y'(t)=\sin(y+t)\text{.}$$ I would start by substituting $z(t)=y(t)+t$ to get an ODE in $z(t)$, but then I'm not sure about how to substitute back my solution to check if it's correct or not$\dots$ How do I transition to SSL without affecting PageRank? "Your Sites" in Android left sidebar shown in unpredictable order In the Android app, left sidebar, there is an editable list of "Your Sites". In the editing pane, the sites are re-orderable (although awkwardly), and the order one places the sites in there is preserved, even after quitting the app and returning to this pane. One expects that order to be reflected in the "Your Sites" portion of the left sidebar when the editing pane is closed, but it is not.  I'm not sure what is determining the order of the sites in the left sidebar, it doesn't seem to be by date they were "pinned" into the list one wants to show, either. Modular arithmetic problem (mod $13$) $$\large2017^{(2020^{2015})} \pmod{13}$$  I am practicing for my exam and I can solve almost all problem, but this type of problem is very hard to me. In this case, I have to compute this by modulo $13$. How to create an iso from current installation I installed Ubuntu 14.04.1 on one of my laptops and now I want distribute that exact installation to a few of my friends. I tried making an iso with Gparted on a live session but it makes a 500 GB file (I've only used around 8 GB) .   Thanks in Advance ! I use ubuntu to deal with daily job. Now I buy a new laptop, and I want to migrate my whole system(programs, packages, data, settings, etc) to the new machine.  I know I can copy my home folder to new machine and I will get (almost) all data and settings. But is there a safe way to copy the whole system? Or it's a bad idea?