I apologize in advance for my naive question but I'm new to Linux and eager to learn. I am experiencing the same problem already commented by others, and it is the impossibility to log-in Ubuntu 14.04 after upgrade. After entering the password, I am redirected to the log-in page again. I followed the instructions appeared in this thread but was unable to solve the issue:  It seems that I need to edit the system file /etc/fstab but once having accessed to the terminal from the log-in page and cd to the proper directory, I don't know how to edit this file.  Your valuable feedback is highly appreciated, thanks.
My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M
Why is it not possible to overload class templates? How would I remove the border from an iframe embedded in my web app? An example of the iframe is:  &lt;iframe src="myURL" width="300" height="300"&gt;Browser not compatible.&lt;/iframe&gt;   I would like the transition from the content on my page to the contents of the iframe to be seamless, assuming the background colors are consistent. The target browser is IE6 only and unfortunately solutions for others will not help. Wires do not connect in Circuitikz I've been trying to use relative coordinates to make my drawings more precise but it seems I don't know how the command \node works since I've been having this problem while connecting a circuit element to another:    I'm trying to eliminate the blank between the two wires.  This is the minimal code:  \documentclass{book} \usepackage[siunitx,RPvoltages]{circuitikz} %Circuit Schematics/Diagram \usetikzlibrary{arrows,shapes,calc,positioning} \begin{document}     \begin{circuitikz}             \path (0,0) coordinate (C);             % Comparatore             \path (C) + (0,-1) + (1,0) coordinate (com) node[above]{};             \path (com) + (1.5,-1) node[op amp] (comp) {};             % Collegamenti Comparatore             \node (G1) at ([shift=({-1.3cm,0cm})]comp.-) {};             \draw (G1) -- (comp.-);             \node (G2) at ([shift=({-1.3cm,0cm})]comp.+) {};             \draw (G2) -- (comp.+);             \draw (C) -- (G1); % Collegamento Rettificatore - Comparatore         \end{circuitikz} \end{document}   Thanks for any help! What is the best way to globally change the amount of vertical space between items in list environments? Window title in bottom of Activities overview is not visible when opening multiple windows When does function composition commute? I've read that function composition "generally does not commute."  Not counting compositions involving the identity function, and compositions of a function and its inverse, are there examples of functions on the reals (for example) $f, g$ where $fg = gf$ outside of these cases? Well, may be this is not really useful, but I've thought if it was possible to put all the document in one long page. I mean, if your document is going to be read in a computer, mix all the pages in a continuous page. If your document has 90 pages (A4), where each one is 21cm by 29.7cm the continuous document should be (more or less) one page which is 21cm by 90 · 29.7 = 2673cm. Is this possible? EDIT: Some things I would like to achieve:  The \newpage, \chapter{}, \part{}, etc. shouldn't go to a new page, they should only add more vertical space. The package pdfpages should add the pages continuously with almost no space between them. The titlepage, in this case, has a different color, so it could go alone in a basic A4 page (just to make things easier).  Question Is this possible? How to convert a 3 column csv file into a table (or matrix) I have an CSV input file format like this, with a nucleotide sequence in field 1, text in field 2, and an integer in field 4:  ATGC,CD3,56 ATGC,CD4,67 ATGC,IgD,126 ATGC,IgM,127 AGTC,CD3,67 AGTC,CD4,78 AGTC,IgD,102 AGTC,IgM,89 TCGA,CD3,334 TCGA,CD4,123 TCGA,IgD,456 TCGA,IgM,80 CGTA,CD3,54 CGTA,CD4,32 CGTA,IgD,82 CGTA,IgM,117   I opened this CSV file using Numbers in Mac it's display as 3 columns format, however, I want to convert it to the table(or Matrix) format (also a CSV file), making the first column, the nucleotide sequences, into a header, and want the result to also look like a table (or Matrix):       ATGC  AGTC  TCGA  CGTA CD3  56    67    334   54 CD4  67    78    123   32 IgD  126   102   456   82 IgM  127   89    80    117   Below is a section from my real input CSV file (sample input.txt):  AGAATAGTCTGATTCT,-,,38 AGAATAGTCTGATTCT,AnnexinV,,51 AGAATAGTCTGATTCT,CD127,,39 AGAATAGTCTGATTCT,CD138,,3 AGAATAGTCTGATTCT,CD14,,2 AGAATAGTCTGATTCT,CD16,,4 AGAATAGTCTGATTCT,CD19,,10 AGAATAGTCTGATTCT,CD20,,6 AGAATAGTCTGATTCT,CD24,,21 AGAATAGTCTGATTCT,CD25,,4 AGAATAGTCTGATTCT,CD27,,87 AGAATAGTCTGATTCT,CD3,,235 AGAATAGTCTGATTCT,CD34,,5 AGAATAGTCTGATTCT,CD38,,18 AGAATAGTCTGATTCT,CD4,,412 AGAATAGTCTGATTCT,CD43,,99 AGAATAGTCTGATTCT,CD5,,430 AGAATAGTCTGATTCT,CD56,,3 AGAATAGTCTGATTCT,CD8,,7 AGAATAGTCTGATTCT,IgD,,4 AGAATAGTCTGATTCT,IgM,,2 TGTGGTAGTTCGTCTC,-,,9 TGTGGTAGTTCGTCTC,AnnexinV,,42 TGTGGTAGTTCGTCTC,CD127,,6 TGTGGTAGTTCGTCTC,CD138,,4 TGTGGTAGTTCGTCTC,CD16,,40 TGTGGTAGTTCGTCTC,CD19,,7 TGTGGTAGTTCGTCTC,CD20,,2 TGTGGTAGTTCGTCTC,CD24,,24 TGTGGTAGTTCGTCTC,CD25,,2   How can I do this using Linux text formatting commands? Legitimate edits of less than 6 characters Is it possible for test error to be lower than training error Is it possible to have test error lower than training error?  I have a classification problem with 2000 samples, 500 of which are positives, 1500 are negatives. I split my data into 70% training data, 30% test data.  Run random forest with 200 estimators and cv=10. I did this several times and compared the recall and precision score and notice the scores for my test set is significantly better. Is this possible? How to count number of bases and subspaces of a given dimension in a vector space over a finite field? Let $V_{n}(F)$ be a vector space over the field $F=\mathbb Z_{p}$ with $\dim V_{n} = n$, i.e., the cardinality of $V_{n}(\mathbb Z_{p}) = p^{n}$. What is a general criterion to find the number of bases in such a vector space? For example, find the number of bases in $ V_{2}(\mathbb Z_{3})$. Further, how can we find the number of subspaces of dimension, say, $r$?   I need a justification with proof. I have a formula, but I am unable to understand the basic idea behind that formula. Non-normality in residuals Characterize the groups $G$ for which the map $\iota: G \to G$, sending $x \mapsto x^{-1}$ for all $x \in G$, is an automorphism of $G$ I have trouble on this question: "Characterize the groups G for which the map $$\iota: G \to G$$ sending $$x \mapsto x^{-1}$$ for all $x \in G$, is an automorphism of $G$." From  post I have seen that $G$ must be abelian. Can anyone propose another characteristic of $G$ that I can derive from the given conditions besides abelian? Thank you so much!! In a bash shell script, writing a for loop that iterates over string values Class with single method -- best approach? 'both in terms of' or 'in terms of both'? Tilde (~) File in Macintosh Directory Last night I discovered what looks like an unusual file named "~" (tilde) in the root of my "Macintosh HD" directory on my MacBook.    Finder reports the file is 2.2MB in size, of kind "TextEdit.app Document", and was created on 22nd January 2014 (so about a month ago).  I haven't noticed any operational issues with OS X or it's applications.   I haven't yet touched the file but would obviously like to remove it.  I am very conscious that '~' is a special alias to the user home directory and thus I would appreciate any recommendations in removing the file in a safe manner that isn't likely to nuke my home directory or screw up the operation of applications or OS X. I don't know whether to delete or rename and whether to use Finder or the command line.   It's entirely possible that I created the file by accident since I've recently been drafting and running various shell scripts that use the ~, user home alias.  MacBook Pro 15" (Retina, Mid 2012) Yosemite I frequently login to a server, then cd into a specific directory. Is it possible to simplify these two commands into one?   ssh bob@foo   cd /home/guest   I'd like to avoid changing anything on 'foo' if possible, as I'll have to clear it with the server administrator. I use bash, but I am open to answers in other shells. Usage of "as if" as interjection My question concerns the usage of "as if" as an idiomatic interjection. The references I have consulted (etymonline, online dictionaries, etc.) seem to agree that "as if" is used in this context to convey incredulity or doubt. This is how I have always thought of it.  The other day, I was with friends who used "as if" to express their surprise and joy about a wedding proposal. They weren't being sarcastic or incredulous; they were genuinely happy about the proposal. Here is a loosely paraphrased version of what they said:  "As if they're getting married!"  Is my friends' usage of "as if" standard? Is it a primarily regional distinction? (I am in Ontario, Canada right now.) The closest example we could come up with is someone says "I can't believe that you won first prize!" Of course, the person can and does believe it, so their words ought not to be taken literally. Is it the same idea with "as if"? About finding the function such that $f(xy)=f(x)f(y)-f(x+y)+1$