I am trying to create a table in which a column consists entirely of chemical formulae. I would like to use the array package to automatically insert the \ce{...} command, taking the cell's content as argument.   I understand from &ldquo; &rdquo; that \bgroup and \egroup only work for replacements for low level commands like \textbf. Unfortunately I do not understand how to use the realboxes package provided there to make it work. I cannot assess if it is appropriate for that task in the first place.  Here is a minimal not working example of what I am trying to do:  \documentclass{article} \usepackage[version=4]{mhchem} \usepackage{array} \begin{document}   \begin{tabular}{&gt;{\textbf\bgroup}l&lt;{\egroup}%                   &gt;{\ce\bgroup}l&lt;{\egroup}}\hline     R1 &amp; -C6H5 \\     R2 &amp; -C6H4F \\\hline   \end{tabular} \end{document}
I want to apply a macro to all the cells of a column with the cell content as the input to the macro. Is this possible?  For example if the cell contents have the word TEST, the macro should take TEST as its argument.
Is there a way to substring a string in Python, to get a new string from the third character to the end of the string?  Maybe like myString[2:end]?  If leaving the second part means 'till the end', and if you leave the first part, does it start from the start? Are there any studies on the use of justified text in web apps? How does justification affect screen legibility?  Example of justified text: What's up with the operating voltages 5 V, 3.3 V, 2.5 V, 1.8 V, etc.? Index and length must refer to a location within the string Output the common lines (similarities) of two text files (the opposite of diff)? How to only append to clipboard (but not overwrite current data)? I have a rather large file, I need to copy the entire contents somewhere, but when I scroll down the page all the data I have selected becomes unselected. I could just copy and paste block by block, but I would find it much easier as there is a lot of data, to just be able to append the contents to the end of the current clipboard data. Is that possible?  That is so that I can have a keyboard shortcut which will enable me to copy this to the clipboard:  I am some nice new text.   When this is what is already there:  I am the old text.   And have it look like this when pasted:  I am the old text. I am some nice new text.   So there are 3 things that I would really like from this (I would have 3 separate keyboard shortcuts to do this):   Append the data to the end of the clipboard and have it put in a RETURN before it (as shown in the example above). Append the data to the end of the clipboard but have it so that there is not RETURN before it so that it would continue on on the same line initially. Have all this but so that the data is put at the beginning of the clipboard before all the data which is currently there.   I am running Ubuntu GNOME 16.04 with GNOME 3.20. Where in the world is tikzlibraryhobby.code.tex? I was trying to reproduce Claudio Fiandrino's answer to .  However, I do not have the hobby package by Andrew Stacey in my local distribution.  After reading  and , I looked at the latest  (build on December 7, 2012) but could not located the hobby package in it.  I found  but do not know where each file is supposed to go in my distribution.  How do I add the hobby package? In general, what would be the easy way to get any new TikZ package installed in a Mac?  EDIT:  I have used the drag-and-drop (mac) method as described below.  (1) Drag pml3array.sty file to /Users/Username/Library/texmf/tex/latex folder. (2) Drag hobby.code.tex file to /Users/Username/Library/texmf/tex/generic/pgf/math folder. (3) Drag pgflibraryfpu.code.tex to /Users/Username/Library/texmf/tex/generic/pgf/libraries folder. (4) Drag tikzlibraryhobby.code.tex to /Users/Username/Library/texmf/tex/generic/pgf/frontendlayer/tikz/libraries folder.  I no longer get the hobby cannot be found error message.  But, is this correct? How do I hide a process in Task Manager in C#? I have a requirement to hide a process in Task Manager. It is for Intranet scenario. So, everything is legitimate. :)   Please feel free to share any code you have (preferably in C#) or any other techniques or any issues in going with this route.  Update1: Most of the users have admin privileges in order to run some legacy apps. So, one of the suggestion was to hide it in task manager. If there are other approaches to prevent users from killing the process, that would be great.  Update2: Removing the reference to rootkit. Somehow made this post look negative. sftp: upload all files, directories and sub-directories contained in a folder On machine A I have the folder /home/a/  On machine B I have the folder /home/b/  I wish transfer all files, directories and sub-directories of /home/a in /home/b with sftp On machine A I tried the commands: sftp fibon82@machineB.com put /home/a/* /home/b/  but it doesn't work, i get the error message: &quot;skipping non-regular file /home/a/a1&quot;... [a1 is a sub-directory of a] How could I modify the put instruction? Thanks! :) EDIT: I solved using scp: scp -r /home/a/ fibon82@machineB.com:/home/b/ Systems of linear differential equations - eigenvectors Solving $x^p + y^p = p^z$ in positive integers $x,y,z$ and a prime $p$ The question is from Zeitz's ''The Art and Craft of Problem Solving:"      Find all positive integer solutions $x,y,z,p$, with $p$ a prime, of the equation $x^p + y^p = p^z$.   One thing I noticed is that   $$ \frac{x^p + y^p}{x + y} = \sum_{i=0}^{p-1}x^{(p-1)-i}(-y)^i \implies (x+y) |p^z \implies x + y = p^n, \text{ }n &lt; z   $$  It is also not hard to determine all solutions for $p =2$. After this, however, I am at a loss. I don't know what restrictions I can impose to try to narrow down the solution set; for example, the class of solutions  $$ p=3, x = 3^n, y = 2\cdot3^n, z = 2 + 3n $$  for $n \ge 0$ show that $x+y = p^n$ cannot be sharpened. (Let me note that these are the only other solutions I have found besides the ones for $p = 2$.)  Could anybody give me a push in the right direction on this problem? What translation occurs when writing to a file that was opened in text mode that does not occur in binary mode? Specifically in MS Visual C.  unsigned char buffer[256]; for (int i = 0; i &lt; 256; i++) buffer[i]=i; int size  = 1; int count = 256;   Binary mode:  FILE *fp_binary = fopen(filename, "wb"); fwrite(buffer, size, count, fp_binary);   Versus text mode:  FILE *fp_text = fopen(filename, "wt"); fwrite(buffer, size, count, fp_text); $M$ connected $\iff$ $M$ and $\emptyset$ are the only subsets of $M$ open and closed at the same time I'm trying to understand this proof that:  $M$ connected $\iff$ $M$ and $\emptyset$ are the only subsets of $M$ open and closed at the same time  Which is:  If $M=A\cup B$ is a separation, then $A$ and $B$ are open and closed. Recriprocally, if $A\subset M$ is open and closed, then $M = A\cup(M-A)$. What? I know that if $M=A\cup B$ is a separation, $A$ and $B$ are both open. But why closed? Also, the 'recriprocally' part is totally nonsense to me. Anybody could help?  Also, there's another proof, which states: $M$ and $\emptyset$ are the only subsets of $M$ at the same time closed and open $\iff$ if $X\subset M$ has empty boundary, theb $X=M$ or $X=\emptyset$  which is proved as the following:  given $X\subset M$, we know the condition $X\cap \partial X = \emptyset$ implies $X$ is open, while the condition $\partial X \subset X$ implies $X$ is closed. Then, $X$ is open and closed $\iff$ $\partial X = X\cap \partial X = \emptyset$, this show $\iff$ for the theorem above.  First of all, I think that the condition $X$ has boundary empty implies that $X\cap \partial X$ is empty, but who said anything about $\partial X\subset X$? Also, where's the $\rightarrow$ of this proof? I can only see $\leftarrow$ There have been a few questions regarding installing this package in the past, but they now seem to be out of date. I'm using MiKTeX 2.9 and TexMaker. When I try \usepackage{mathtools} in TexMaker it will try to install the package for me but will fail. I took the advice given in this thread:   As suggested I tried installing the mh package using the MiKTeX Package Manager, unfortunately I get the "unknown archive size" error, which I have read means that the package no longer exists. Another thread (lost the link) said you can use the MiKTeX Package Manager to directly install mathtools, however I do not see mathtools listed anywhere in the MiKTeX Package Manager...   So I ask, is the package under a different name? Are there any other ways to install this package? How to get the location of a program in Ubuntu? For example I have Oracle, how to get the folder racine (location) of Oracle? SEO (or other) problems with a 404? When $f(x+1)-f(x)=f'(x)$, what are the solutions for $f(x)$? How can I benchmark my HDD? I've seen commands to benchmark one's HDD such as this using dd:  $ time sh -c "dd if=/dev/zero of=ddfile bs=8k count=250000 &amp;&amp; sync"   Are there better methods to do so than this? There are no book recommendations for Astrophysics here. I will write my own answer, but I am also interested in what are others' views on the question (I will NOT mark my own answer as the best one). Create a bootable USB on a Mac to install Ubuntu on a PC