There are -p option in mkdir command to create parent directories as needed wolf@linux:~$ tree .  0 directories, 0 files wolf@linux:~$  wolf@linux:~$ mkdir dir1/dir2/dir3 mkdir: cannot create directory ‘dir1/dir2/dir3’: No such file or directory wolf@linux:~$  wolf@linux:~$ tree .  0 directories, 0 files wolf@linux:~$  wolf@linux:~$ mkdir -p dir1/dir2/dir3 wolf@linux:~$  wolf@linux:~$ tree  . └── dir1     └── dir2         └── dir3  3 directories, 0 files wolf@linux:~$   Are there similar features in vi or touch command? In this case, I would like to create file authorized_keys in nonexistent directory .ssh with vi or touch. authorized_keys is a file, and not a directory. Hence, mkdir -p .ssh/authorized_keys command is not applicable here as authorized_keys will be created as directory, not a file. wolf@linux:~$ ls .ssh ls: cannot access '.ssh': No such file or directory wolf@linux:~$   Would it be possible to do this without mkdir .ssh or mkdir -p .ssh? wolf@linux:~$ touch .ssh/authorized_keys touch: cannot touch '.ssh/authorized_keys': No such file or directory wolf@linux:~$
mkdir -p will create a directory; it will also make parent directories as needed.  Does a similar command exist for files, that will create a file and parent directories as needed?
pgfplots legend style for plots with error bands What does "overfull hbox" mean? (Why is there a black mark at the end of a line?) I often see output from TeX with the warning overfull hbox, badness 10000. What does this message mean? When closing a question as a duplicate there is a text box which says: "search, or enter a question link or numeric id". You can copy and paste a question link into here, but this fails if the URL starts with https:// instead of http://, with the message "Your search returned no matches; please try a different search". Disable HTTPS for a domain that shares IP with another domain that is under HTTPS I am running into a weird problem trying to disable HTTPS for one domain, but the other domain has HTTPS. They both are different websites running on a dedicated server, sharing the same IP address for the domains.  However, I have a domain that does not have a SSL certificate, but the other does. I want to disable HTTPS for the non-certified domain while leaving the other domain with HTTPS on.  I have two different separate vhosts in /etc/nginx/sites-enabled/,   domain1.org (no HTTPS)  server {      listen                      80;     server_name                 www.domain1.org domain1.org;     root                        /var/www/domain1.org;     index                       index.html index.php index.htm;      error_log                   /var/www/logs/domain1.errors.log;      [ ... ]   domain2.com (with HTTPS)  server {      listen                      443 ssl;     server_name                 domain2.com www.domain2.com;      # INCLUDE SSL CERTIFICATE     include                     sites-enabled/domain2_ssl_include;       root                        /home/domain2/www/www;     index                       index.html index.php index.htm;      [ ... ]   I've included a listener to the port 443 for domain1.org, but once I do that, I get an aborted error from Firefox saying (when accessing ):     This Connection is Untrusted      You have asked Firefox to connect securely to domain1.org, but we can't confirm that your connection is secure.   I opened the technical data, it appears that the domain1.org is using the domain2.com SSL certificate:     domain1.org uses an invalid security certificate.      The certificate is only valid for the following names:    *.domain2.com , domain2.com        (Error code: ssl_error_bad_cert_domain)   So I added this to domain1.org vhost configuration:  server {      server_name                 domain1.org www.domain1.org;      listen                      443 ssl;      rewrite ^ http://domain1.org permanent; }   Which still gets me prompted with the Firefox error.  Now... when I access to , I get an 400 error from nginx saying this:     400 Bad Request      The plain HTTP request was sent to HTTPS port   I am not entirely sure what to do, disabling the https with ssl off; has no effect. How can I actually disable HTTPS for domain1.org but not for domain2.com?  I am using Ubuntu 12.04 running nginx 1.2.6. Connect external hard drive to Ubuntu I have an NTFS external hard drive that contains only Windows XP data. How do I connect it to Ubuntu? Using "answer your own question" to advertise completed open source project? "In" and "on": How can I decide which one to use for vehicles? Examples:   In a car, van, etc. On a bus, boat, motorcycle, etc.   How can one decide which preposition to use? Is memorization the only way or is there a better way?  Note: People generally explain this by either distinguishing between open and closed vehicles or between large and small vehicles. However, the examples I've given defeat both explanations. Indentation in tcolorbox package I'd like to have the same indentation within a tcolorbox as I have in the rest of the document.  How can I get it?  Thanks.  MWE:  \documentclass[a4paper]{book}  \usepackage{lipsum} \usepackage[most]{tcolorbox}  \begin{document}  \chapter{Example with \texttt{tcolorbox}} \lipsum[1-8]  \begin{tcolorbox}[breakable,enhanced] \lipsum[9-14] \end{tcolorbox}  \end{document}   The first block of text has the typical indentation, but that in the box doesn't. Pre-1972 sci-fi short story or novel: alien(?) tunnel where people try new moves and get destroyed if they're not the correct ones Give a combinatorial proof to show the following for all integers $n \geq 2$. $$2^{n-2} n (n -1) = \sum\limits_{k=2}^n k (k - 1) \binom{n}{k}.$$  I'm completely stumped. I just have no idea how to do this. What I've tried so far has been simplifying the right hand side slightly to $\sum\limits_{k=2}^n \binom{n}{k - 2}$, and then proving that this somehow is equal to some manipulation of the left hand side. I can't seem to find any breakthroughs that way though.  If anyone could help out or point me in the right direction that would be great.  EDIT: I've actually just realized my simplification of the right hand side is wrong. Now I'm even more stuck. I have installed the developer preview for Yosemite.  Huge mistake. Everything in my workspace is broken.  I don't have any sort of backup image. I was wondering if I could re-download Mavericks and run the installer - would that effectively downgrade me back to Mavericks? In a ring, I was trying to prove that for all $a$, $a0 = 0$.  But I found that this depended on a lemma, that is, for all $a$ and $b$, $a(-b) = -ab = (-a)b$.  I am wondering how to prove these directly from the definition of a ring.  Many thanks! Sort and count number of occurrence of lines At what pressure will be particles in a medium be unable to form a sound wave when disturbed? How can this pressure be described mathematically?  My guess is that this would correspond to the point at which the restoring force due to pressure is unable to create a transverse wave and the disturbed particles travel infinitely far away before the hypothetical wave reaches it's amplitude. But I have no idea how you would even begin to start finding a quantitative value for this point. How to start Skype 4 with Ubuntu 12.10? I've installed Skype and it's running all OK but I want it to start automatically when I log with my user.  How can I do that? What are some CD ripping programs for Ubuntu? Can you list the Pros? What are the Cons? For each program there should be a screenshot, sources to install, and instructions to install and use. Android Manifest Restrict To Tablets I have multiple datasets that I am attempting to use principal component analysis (PCA) on in order to infer the underlying structure of the data.  I'm attempting to predict growth increment of conifers (the response which apparently needed to be cube root transformed for my original linear models).  My predictor variables include: continuous (some log-transformed like size-related variables, some compositional, and some traditionally scaled); binary; ordinal; and nominal (of which I'm pretty sure I can order with respect to site productivity).  I'm mostly attempting to make inferences because some of my previous models from linear regression have not produced significant terms corresponding to categories like health or climate and I feel that they should have.  I've read in Joliffe (2002) that I might want to leave my compositional data uncentered.  Forgive my naiveté, but I'm wondering if I should also do this for my binary data.  It also seems that I might not want to scale these since they're already on a 0 - 1 scale but I'm not sure.  After only using my continuous predictors (including compositional variables), it appears that a size principal component makes up the largest portion of the variability and Joliffe also mentions that one might want to attempt a "double-centering" of the log-transformed data if this is the case.  I don't know if this is even possible since the log-transformed data only makes up a small portion of my datasets.  Finally, I should ask if having such a combination of data types will complicate analysis so much that it will make inferences unreliable.  I am currently using R for this analysis.  Thank you. C++11 does not deduce type when std::function or lambda functions are involved The second part of an exercise asks that I show:     There does not exist a surjective bounded linear map from $\ell^2(\mathbf{N})$ to $\ell^1(\mathbf{N})$.     The first part was to show that these two spaces are separable in their respective $L^p$ norms.    I've really hit a wall on this one.  I know, in fact, that there does exist a surjective bounded linear map from $\ell^1(\mathbf{N})$ to $\ell^2(\mathbf{N})$.  So my intuition says that if there were also one going the other way, then the two spaces would have to be isomorphic, which is false .  But I don't know of any such theorem that I could apply to "the category of Banach spaces".    My only other idea is to argue by contradiction using the open mapping theorem, but nothing is coming to me...  My guess is that separability is also going to be important, given the first part of the exercise.  -Thanks.