Adding space between two table of content entries I would like to add additional space between some selected ToC entries.  I can achieve this by adding \bigskip in the title. While this produces the required output it also produces an error (associated with the hyperref package - see below).  So it seems there must be a more correct way of doing this.   What I want to achieve:   MWE:  \documentclass{book}  \usepackage[utf8]{inputenc}  \usepackage[T1]{fontenc}  \usepackage{hyperref} \begin{document} \addcontentsline{toc}{chapter}{Summary\bigskip}  \addcontentsline{toc}{chapter}{Table of contents} \tableofcontents   \addcontentsline{toc}{chapter}{List of figures} \listoffigures   \addcontentsline{toc}{chapter}{List of tables\bigskip} \listoftables   \mainmatter \chapter{Chapter 1} \section{Section} \end{document}     This produces the following error:     Token not allowed in a PDF string (PDFDocEncoding):(hyperref) removing `\@ifnextchar'      Token not allowed in a PDF string (PDFDocEncoding):(hyperref) removing `\bigskipamount'
table of contents: adding a vertical space In a table of contents that has been generated with LaTeX's \tableofcontents command, I would like to add a vertical space before a Chapter item in the table of contents. One way that I have in my notes is to use  \addtocontents{toc}{\protect\vspace{10pt}}   at a desired location in the document so that this gets processed by \tableofcontents to include an appropriate vertical space in the table of contents. I have two questions:   Is the above the correct way to get a vertical space in a table of contents? Why is it necessary to use the \protect command here?   Thank you...
'undefined reference to symbol 'pthread_create@@GLIBC_2.2.5' while compiling bochs I'm trying to compile bochs with this command:  ./configure --with-x11 --with-wx --enable-ne2000 --enable-iodebug --enable-disasm --enable-debugger --enable-e1000 --enable-usb --enable-pci   it works, but then when I run make I got:  usr/bin/ld: gui/libgui.a(gtk_enh_dbg_osdep.o): undefined reference to symbol 'pthread_create@@GLIBC_2.2.5' /lib/x86_64-linux-gnu/libpthread.so.0: error adding symbols: DSO missing from command line   Any Help ? :/ So I know umask can restrict privileged users, using this format umask ugo.  I understand that the read = 4, write = 2, and exec = 1. However, when I type umask, it returns 4 digits which is 0022 or 0073. I have no understanding of how does this work now because there is an extra digit. What is that extra digit and what does 0022 mean? load() method deprecated? Possible Duplicate:             Each post has an indicator which summarises who the post is shared.    What is the difference between these two terms? Should I write summarises or summarizes? StringTokenizer? Convert the String to a char[] and iterate over that? Something else? List contents of tarball in tree format Per the answers  I'm able to list the contents of my tarball in ls format. However, I'd like to be able to list them in tree format, i.e. something like the latter instead of the former:  With tar:  $ tar -tf foo.tar  foo/ foo/baz/ foo/baz/qux/ foo/baz/qux/hisfile.txt foo/bar/ foo/bar/myfile.txt foo/bar/yourfile.txt   With tree:  $ tree foo foo ├── bar │   ├── myfile.txt │   └── yourfile.txt └── baz     └── qux         └── hisfile.txt   Is it possible to do this without extracting the tarball? I'd prefer to have to avoid extracting the tarball due to their size. Regular expression to match non-ASCII characters? What is the easiest way to match non-ASCII characters in a regex? I would like to match all words individually in an input string, but the language may not be English, so I will need to match things like ü, ö, ß, and ñ. Also, this is in Javascript/jQuery, so any solution will need to apply to that. How do I disable "Link Preview" in Chrome? Proof of conservation of energy? How is it proved to be always true? It's a fundamental principle in Physics based on all of our currents observations of multiple systems in the universe. Is it always true to all systems? Because we haven't tested or observed them all. Would it be possible to discover/create a system that could lead to a different result? How are we 100% sure that energy is always conserved? Finally, why did we conclude it's always conserved? What if a system keeps doing work over and over and over with time? I am using QGIS 3.2.0 on a Mac (and also have QGIS 2), and I have a fishnet grid (probably created in Arc) that comprises of nearly 2 million grid cells. As a result, every change I make to the attribute table takes hours, so I can't experiment as I would usually.  I need to label each grid cell such that the north-westernmost cell is "1", and the numbers proceed by rows, until the last number goes into the south-easternmost cell. Using the row-number doesn't work, as that's not how the table is sorted. I've done this before, but cannot remember how. How to remove spikes from switching transistor? Limit of sequence in which each term is defined by the average of preceding two terms We have a sequence of numbers $x_n$ determined by the equality   $$x_n = \frac{x_{n-1} + x_{n-2}}{2}$$  The first and zeroth term are $x_1$ and $x_0$.The following limit must be expressed in terms of $x_0$ and $x_1$ $$\lim_{n\rightarrow\infty} x_n $$  The options are:   A)$\frac{x_0 + 2x_1}{3}$ B)$\frac{2x_0 + 2x_1}{3}$  C)$\frac{2x_0 + 3x_1}{3}$ D)$\frac{2x_0 - 3x_1}{3}$  Since it was a multiple choice exam I plugged $x_0=1$ and $x_1=1$. Which means that all terms of this sequence is $1$,i.e, $$x_n=1, n\in \mathbb{N} $$  From this I concluded that option A was correct.I could not find any way to solve this one hence I resorted to this trick. What is the actual method to find the sequence's limit? QGIS 2.0 - can't select items in Print Composer Try to solve this puzzle:     The first expedition to Mars found only the ruins of a civilization.   From the artifacts and pictures, the explorers deduced that the   creatures who produced this civilization were four-legged beings with   a tentatcle that branched out at the end with a number of grasping   "fingers". After much study, the explorers were able to translate   Martian mathematics. They found the following equation:   $$5x^2 - 50x + 125 = 0$$   with the indicated solutions $x=5$ and $x=8$. The value $x=5$ seemed   legitimate enough, but $x=8$ required some explanation. Then the explorers    reflected on the way in which Earth's number system developed, and found   evidence that the Martian system had a similar history. How many fingers would    you say the Martians had?      $(a)\;10$      $(b)\;13$      $(c)\;40$      $(d)\;25$   P.S. This is not a home work. It's a question asked in an interview. What statistical test to use for discrete predictor and response variables? I'm doing a statistical analysis of a model for college. It's modelling a bear catching fish and I'm asking will the amount of time taken to digest the fish have an effect on the amount of fish caught? (stupid question I know!) So the predictor variable is the amount of fish the bear can eat before it needs to digest and the response variable is the amount of fish it catches. The predictors varies between 1 and 30 in integers and the response is also in integers. I repeated each level of the predictor 5 times creating a sample size of 150 altogether. I was thinking of just using a simple correlation test such as cor.test in R, but I've read online that this is for continuous data. Does that matter or would this test still be appropriate? Thanks a million, Eamon Let $F$ be a field and $f: \mathbb{Z} \to F$ be a ring epimorphism. How do I test a private function or a class that has private methods, fields or inner classes? I often end up issuing complex commands over ssh; these commands involve piping to awk or perl one-lines, and as a result contain single quotes and $'s.  I have neither been able to figure out a hard and fast rule to do the quoting properly, nor found a good reference for it.  For instance, consider the following:  # what I'd run locally: CMD='pgrep -fl java | grep -i datanode | awk '{print $1}' # this works with ssh $host "$CMD": CMD='pgrep -fl java | grep -i datanode | awk '"'"'{print $1}'"'"   (Note the extra quotes in the awk statement.)  But how do I get this to work with, e.g. ssh $host "sudo su user -c '$CMD'"?  Is there a general recipe for managing quotes in such scenarios?.. Why is observing 100 heads for a fair coin flips surprising? Assume that we have a fair coin. We flip it 100 times. The outcome is all heads. Why is it surprising? Doesn't all outcomes have the same probability? Any particular outcome, including irregular ones, would have the same very small probability. Why is it that observing an irregular outcome is less surprising to us than a regular one? Top of answer covered by sticky top bar after clicking direct link