Should I leave a tip in a fully automated restaurant in the USA?
How much to tip in the United States?
Why was the switch statement designed to need a break? Given a simple switch statement  switch (int) {     case 1 :     {         printf("1\n");         break;     }      case 2 :      {         printf("2\n");     }      case 3 :      {         printf("3\n");     } }   The absence of a break statement in case 2, implies that execution will continue inside the code for case 3. This is not an accident; it was designed that way. Why was this decisions made? What benefit does this provide vs. having an automatic break semantic for the blocks? What was the rationale? Get file size before uploading Recommended ways to upgrade AlwaysOn AG from 2014 to 2016 What is the recommended process of upgrading Availability Groups with one Sync Replica from SQL 2014 to 2016?  My understanding is that in-place upgrades are not really liked among database professionals. Is there a way to avoid in-place upgrades in Availability Groups? Is there a possibility to join a 2016 server into an existing 2014 availability group and to failover there, then "kill" one of the other instances and upgrade it? (e.g. by removing/re-installing SQL side-by-side on the same host)  Are there any other upgrade scenarios that we should consider?  The ideal solution would be that we always have 2 online replicas, and that we don't need to do any in-place upgrades. Show that if $a$ and $b$ are positive integers with $(a,b)=1$ then $(a^n, b^n) = 1$ for all positive integers n Comments can now be upvoted and flagged. How do those features work? Do users get rep for their upvoted comments? Do upvoted comments have any effect on comment sorting? And can users see their own comment upvote number somewhere?  Related:  The  about comments Why can templates only be implemented in the header file? Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.) Switching between windows with scroll wheel on Ubuntu Dock Let , $\Delta = B(0,1)$.  If $f:\Delta \rightarrow \Delta$ is holomorphic, and $f(0)=0$, prove that $|f(z)+f(-z)| \leq 2|z|^2$.  My attempt so far:  $\displaystyle f(z) = \sum_{n=0}^{+\infty} a_n z^n = \sum_{n=0}^{+\infty} a_{2n} z^{2n} + \sum_{n=0}^{+\infty} a_{2n+1} z^{2n+1}$  $\displaystyle f(-z) = \sum_{n=0}^{+\infty} a_n (-z)^n = \sum_{n=0}^{+\infty} a_{2n} z^{2n} - \sum_{n=0}^{+\infty} a_{2n+1} z^{2n+1}$  Then, $\displaystyle f(z)+f(-z) = 2  \sum_{n=0}^{+\infty} a_{2n} (z^2)^n =: 2 g(z^2)$  If $g(\Delta) \subset \Delta$, as $g(0) = 0$, I can invoke Schwarz Lemma and I win. However, I don't know how to prove this. Could anyone help me? Thanks! Integral of Sinc Function Squared Over The Real Line Python Script returns unintended "None" after execution of a function Evaluating $\int^\pi_{-\pi} \cos^3(x) \cos(ax)~dx$ I need to evaluate $I = \int^\pi_{-\pi} \cos^3(x) \cos(ax)~dx$ where $a$ is some integer.   I get: $\dfrac{2a(a^2-7)\sin(\pi a)}{a^4 - 10a^2 + 9}$. However $\sin(\pi a)$ is $0$ for all $a$ so $I=0$. But as noted by an answer, there are answers for $a = 1,3,-1,-3$. Test whether string is a valid integer How to run Bash script on startup on Linux? I am running Linux 4.9.11-1.0.0 on my iMX7 dual development board. I have a test.sh file that I would like to run at startup. It currently only has a bunch of echo statements in it (just for testing purposes).   When I flick the switch on the board to turn it on, I see a bunch of initialization stuff come up. I would like the echo statements in my test.sh file to also be displayed in this initialization sequence on startup. Eventually once this is working, the plan is to do real stuff in place of the simple echo statements. I just want to make sure the script is running on startup at this point.  So far I have created the test.sh file and I am able to run it manually after the board has booted up. I have added the following to my /etc/rc.local file before the exit statement at the end:  sh '/home/root/test.sh'   I have verified that this rc.local file has #!/bin/sh -e at the top. I have also done:  $ chown root /etc/rc.local $ chmod 777 /etc/rc.local   Once this was all done, I verified that it should be working properly by typing:  $ /etc/init.d/rc.local start   Everything is working as expected up until this point and I am seeing the echo statements when I do that last step. However, when I go and try to reboot the board, I do not see the echo statements at all in the printed initialization stuff.  What am I missing? Maybe it is actually running on startup but I just don't see the output for some reason? jsp:useBean scope How can I produce the codes to get the symbols of pencil, ruler and compass in LATEX? I'm gonna write a sentence I can draw this figure by using simple tools in my presentation. So I prefer to include symbols pencil, ruler and compass instead of the words simple tools. Is it possible? Pipelined Sed does not work on found filename inside Bash command substitution when invoked from Find "-exec" It looks like 'find', 'bash' and 'sed' in some cases does not work as one expects.  The following example should first create file 'sample.txt', then find the file and finally process it by '-exec' command. The executed command prints found filename, test specimens, and modified filename. The 'sed' command itself is used to replace 'txt' to 'TXT'.  touch sample.txt find ./ -maxdepth 1 -name "*.txt" -exec echo {} $(echo Specimen_before.txt {} Specimen_after.txt |sed -e "s/txt/TXT/g") \;   The expected output is:     ./sample.txt Specimen_before.TXT ./sample.TXT Specimen_after.TXT   Instead it produces:     ./sample.txt Specimen_before.TXT ./sample.txt Specimen_after.TXT   (the example has been tested also with old-school command substitution through backquotes '`' with the same result)  What am I doing wrong? Redshift of merging black holes How did they found that the gravitational waves where emitted at redshift $z=0.09$?  I understand the measurement of redshift for an electromagnetic wave where we have measured in a lab various transitions and therefore we can make a comparison with the wavelength we receive.  But how can they manage to get the redshift for the emitter of gravitational waves, since we have no reference? Comment authors are not getting migrated Wi-Fi speed on my laptop with RTL8723DE is a bit slow and its range is also very low, what to do? My Wi-Fi connection seems to be very weak and the range is very low. It drops by two bars if I just move to the next room and by two if just step outside.  The speed is also not fast as compared to what I get from the router on my desktop .  My laptop is a HP laptop with RTL8723de module. Can anyone help me in bumping up my Wi-Fi speed?  Result of lspci -nnk | grep 0280 -A3:  03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:d723] Subsystem: Hewlett-Packard Company Device [103c:8319] Kernel driver in use: rtl8723de Kernel modules: rtl8723de Flag Options Missing - Is this a bug? This is normally what I see when flagging a post:   Which then provides the following options:    I have come across this problem before. Where I have wanted to flag a question, as not belonging here, but only have limited options.    When this happens, I use a custom flag and write in the reason, but am not happy doing so.  Is this a bug?   What is the best thing to do?