Call me a noob, 'cause I really am, but what does 'foo' mean? I have seen it a lot. but I don't know what it means. Could someone clarify? All help is appreciated.
I hope this qualifies as a programming question, as in any programming tutorial, you eventually come across 'foo' in the code examples. (yeah, right?)  what does 'foo' really mean?  If it is meant to mean nothing, when did it begin to be used so?
Clicking links in pdfs opened with Okular opens Abiword (instead of the default browser) I work with Xubuntu 12.04 and use Okular (version 0.14.3) to view pdf files. If I click a web link in a pdf file (created with "pdflatex" using the "hyperref" package), "Abiword" (It's a word-processing software, like Libreoffice writer) is opened instead of my default browser google-chrome. How can I change this behavior? The settings in Okular do not seem to provide a solution.   (Note that I set google-chrome as the preferred application for web browsing under Settings -> Preferred Applications, so that's not the problem). How to modify a text file? I'm using Python, and would like to insert a string into a text file without deleting or copying the file. How can I do that? Proof for $e^z = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{z}{x} \right)^x$ Q1: Could someone provide a proof for this equation (please focus on this question):   $$e^z = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{z}{x} \right)^x$$  Q2: Is there any corelationn between above equation and the equation below (this would benefit me a lot because i at least know how to proove this one):  $$e = \lim \limits_{x \rightarrow \infty} \left( 1 + \frac{1}{x} \right)^x$$ My international conference in Europe this May has been canceled due to the COVID-19. I have a ticket, purchased from TAP air Portugal, from Toronto, Canada to Lisbon. Because it is a non-refundable fare, they don't want to give a refund.  They won't allow me to reschedule later than May 31 of this year. This won't be useful for me.  What options do I have? I'd prefer to get a full refund.  (I am a US citizen if it matters)  Note: They offered to refund just the taxes, which is about 10% of the value. That's not horrible, but I'd rather have the whole thing returned. When is the Laplace transform of a function continuous? Are there any general conditions on a function so that its Laplace transform is continuous? e.g. what conditions on $f:\mathbb {R} \rightarrow \mathbb {R}$ guarantee that its Laplace transform  $$F\left(s\right)=\int_{0}^{\infty}f\left(t\right)e^{-st}dt$$ is continuous? It seems to me that if $f$ has compact support and is bounded, then it ought to be. The idea I have is that we get  $$\left|F\left(s'\right)-F\left(s\right)\right|\leq\int_{0}^{y}\left|f\left(t\right)\right|\left|e^{-st}\right|dt$$ by making $s'$ and $s$ close enough, it seems we can make the RHS arbitrarily small. I haven't been able to complete a proof. Additionally, can we change the assumptions? Are there more natural assumptions to get continuity? I am travelling to Athens, Greece, shortly, and have seen . Should I be worried? Should I cancel my trip?  Update  It's fine, taxis are currently on strike, but Syntagma Sqaure is fine: Index entries duplicated for captions How to align prices in columns when both 2 digit and 4 digit variations of a price exist? I am trying to display data similar to coinmarketcap with prices for coins, some above 1$ in which case they are rounded to 2 zeroes, some below 1$ in which case they have 4 digits following the decimal. I saw a bunch of posts here where people have suggested to use right alignment for numeric applications/prices  Approach 1 Decimal aligned   1. $13,700.05  2.      $0.0048   Approach 2 Right aligned   1. $13700.05  2.   $0.0048   Which of these approaches do you suggest? Thank you for your time Shell script throws a not found error when run from a sh file. But if entered manually the commands work I'm trying to use the following script to generate a sitemap for my website. When I run it as sh thsitemap.sh I get an error like this and creates an empty sitemap.xml file:  thsitemap.sh: 22: thsitemap.sh: [[: not found thsitemap.sh: 42: thsitemap.sh: [[: not found thsitemap.sh: 50: thsitemap.sh: Syntax error: "(" unexpected   But as the same user root when I manually copy and paste these lines on the terminal, it works without any error and the sitemap.xml file have all the urls. What's the problem? How can I fix this?  #!/bin/bash ############################################## # modified version of original http://media-glass.es/ghost-sitemaps/ # for ghost.centminmod.com # http://ghost.centminmod.com/ghost-sitemap-generator/ ############################################## url="techhamlet.com" webroot='/home/leafh8kfns/techhamlet.com' path="${webroot}/sitemap.xml" user='leafh8kfns'       # web server user group='leafh8kfns'      # web server group  debug='n' # disable debug mode with debug='n' ############################################## date=`date +'%FT%k:%M:%S+00:00'` freq="daily" prio="0.5" reject='.rss, .gif, .png, .jpg, .css, .js, .txt, .ico, .eot, .woff, .ttf, .svg, .txt' ############################################## # create sitemap.xml file if it doesn't exist and give it same permissions # as nginx server user/group if [[ ! -f "$path" ]]; then     touch $path     chown ${user}:${group} $path fi  # check for robots.txt defined Sitemap directive # if doesn't exist add one # https://support.google.com/webmasters/answer/183669 if [ -f "${webroot}/robots.txt" ]; then SITEMAPCHECK=$(grep 'Sitemap:' ${webroot}/robots.txt)     if [ -z "$SITEMAPCHECK" ]; then     echo "Sitemap: http://${url}/sitemap.xml" &gt;&gt; ${webroot}/robots.txt     fi fi ############################################## echo "" &gt; $path  # grab list of site urls list=`wget -r --delete-after $url --reject=${reject} 2&gt;&amp;1 |grep "\-\-"  |grep http | grep -v 'normalize\.css' | awk '{ print $3 }'`  if [[ "$debug" = [yY] ]]; then     echo "------------------------------------------------------"     echo "Following list of urls will be submitted to Google"     echo $list     echo "------------------------------------------------------" fi  # put list into an array array=($list)  echo "------------------------------------------------------" echo ${#array[@]} "pages detected for $url"  echo "------------------------------------------------------"  # formatted properly according to # https://support.google.com/webmasters/answer/35738 echo "&lt;?xml version=\"1.0\" encoding=\"UTF-8\"?&gt; &lt;urlset xsi:schemaLocation=\"http://www.sitemaps.org/schemas/sitemap/0.9  http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns=\"http://www.sitemaps.org/schemas/sitemap/0.9\"&gt;" &gt; $path  echo '     ' &gt;&gt; $path;    for ((i=0;i&lt;${#array[*]};i++)); do echo "&lt;url&gt;     &lt;loc&gt;${array[$i]:0}&lt;/loc&gt;     &lt;lastmod&gt;$date&lt;/lastmod&gt;     &lt;changefreq&gt;$freq&lt;/changefreq&gt;     &lt;priority&gt;$prio&lt;/priority&gt; &lt;/url&gt;" &gt;&gt; $path    done echo "" &gt;&gt; $path echo "&lt;/urlset&gt;" &gt;&gt; $path  # notify Google # URL encode urls as per https://support.google.com/webmasters/answer/183669 if [[ "$debug" = [nN] ]]; then     wget  -q --delete-after http://www.google.com/webmasters/tools/ping?sitemap=http%3A%2F%2F${url}%2Fsitemap.xml      rm -rf ${url} else     echo "wget  -q --delete-after http://www.google.com/webmasters/tools/ping?sitemap=http%3A%2F%2F${url}%2Fsitemap.xml"      echo "rm -rf ${url}" fi echo "------------------------------------------------------"  exit 0 For me the distinction between sites is purely topical. I get that there's a right and a wrong place to ask questions, but I regularly ask questions across a number of sites. They all log me in (in a weird sort of way), and now there's the global inbox.  I've read that there's a feed  and that there's a  but neither of these are what I want.  What I'd like is to have an RSS feed from my global inbox, i.e. to include notification of updates to my public questions, answers, comments. Is this possible? How do I prevent mouse movement from waking up a suspended computer? How to install ns2 on Ubuntu I tried different options to enable hibernate in Ubuntu 20.04 but nothing is working. How can I enable hibernate option in Ubuntu 20.04? What figure of speech is this? Convergence of $\sum _{n=1}^{\infty }\left\{ 1-n\log \frac {2n+1} {2n-1}\right\} $ Prove that $(ma, mb) = |m|(a, b)\ $ [GCD & LCM Distributive Law] I'm trying to prove that $(ma, mb) = $|$m$|$(a, b)$ , where $(ma, mb)$ is the greatest common divisor between $ma$ and $mb$. My thoughts: If $(ma, mb) = d$ , then $d$|$ma$ and $d$|$mb$ → $d$|$max + mby$ → $d$|$m(ax+by)$. This implies that $d$|$m$ or $d$|$(ax+by)$. This is the same as  $d$|$m$ or $d$|$a$ and $d$|$b$, so $d$|$m$ or $d$|$(a,b)$. This is the same as $d$|$m|$ or $d|(a,b)$, so $d$|$|m|(a,b)$. I don't know what to do. Difference between 'such as' and 'like' This one never ceases to confuse me. When to use 'such as' and when to use 'like' while giving examples? Is there any clear rule?        Metros like Mumbai, Delhi and Karachi are unsafe after dark.    Metros such as Mumbai, Delhi and Karachi are unsafe after dark.       (Before anyone points out, Delhi and Karachi are unsafe round-the-clock, but it's just an example.) Change \textwidth and \textheight in mid-document Best way to list files in Java, sorted by Date Modified? I want to get a list of files in a directory, but I want to sort it such that the oldest files are first.  My solution was to call File.listFiles and just resort the list based on File.lastModified, but I was wondering if there was a better way.  Edit: My current solution, as suggested, is to use an anonymous Comparator:  File[] files = directory.listFiles();  Arrays.sort(files, new Comparator&lt;File&gt;(){     public int compare(File f1, File f2)     {         return Long.valueOf(f1.lastModified()).compareTo(f2.lastModified());     } }); How to combine multiple commands in terminal? I have the following commands.  cd import zcat urls1.sql.gz | mysql -u root -p urls cd /var/www/project1/ nano 1.php   As of now I'm executing it one by one.  Is there a way to combine those commands in one line?