I have a file named #%2Amerge%2A#4984jjK#.   # starts a comment in bash. So how can I remove the file?  Thanks.
I was running a Python script that malfunctioned and used sudo to create a file named &gt;.  How can I get rid of this file?  Of course, when I try sudo rm &gt;, I get the error bash: syntax error near unexpected token 'newline', because it thinks I'm trying to redirect the output of rm.  Its permissions are -rw-r--r--.
I know this has probably been asked before, but I couldn't find it with Google.   Given   Linux Kernel No configurations that change $HOME bash   Will ~ == $HOME be true? Open Source Command Line Tools to Remove Hyperlinks in PDFs? Are there any Open Source Tools to Remove PDF links in Ubuntu.  I use PDFtk and i am not able to find any internal links in it. Due to the Internal links my python script that uses PyPdf to merge the PDF files into one file fails. Folland, "Real Analysis", Chapter 5.3, Exercise 36:     Let $\mathcal{X}$ be a separable Banach space and let $\mu$ be   counting measure on $\mathbf{N}$.  Suppose that   $\left\{x_n\right\}_1^\infty$ is a countable dense subset of the unit   ball of $\mathcal{X}$, and define $T \colon L^1(\mu) \to \mathcal{X}$   by $Tf = \sum_1^\infty f(n) x_n$.  (a)  $T$ is bounded.  (b)  $T$ is   surjective.   I have proved (a).  I would like help on (b).  Here are my ideas so far.    Say we want to show $y \in \mathcal{X}$ is in the image of $T$.  Reduce to the case $||y|| = 1$ and let $x_{n_m} \to y$.  My thought is to produce for each $N$ a function $f_N \in L^1(\mu)$ such that $||y - \sum_n^\infty f(n)x_n|| &lt; 1/N$ and also such that the $f_N$ converge in $L^1(\mu)$ to some $f \in L^1(\mu)$.  Then use the continuity of $T$ to conclude $T(f) = y$.    The way I have been setting up my inequalities is as follows. Pick $M_N$ such that for all $m &gt; M_N$, $||y - x_{n_m}|| &lt; 1/N$.  Then I want to define $f_N$ so that $$\sum_n^\infty f_N(n) = \sum_{m &gt; M_N}^\infty f_N(m) = 1, $$ hence $$||y - T(f_N)|| = ||\sum_{m &gt; M_N}^\infty f_N(m) y + \sum_n^\infty f_N(n)x_n|| \leq \sum_{m &gt; M_N}^\infty f_N(m) || y - x_{n_m} || &lt; \frac{1}{N}. $$  Presumably, if the $f_N$ are appropriately chosen, then I can find a dominating function and apply the Dominated Convergence Theorem to finish up.    However, getting all these hypotheses to hold simultaneously has been difficult.  In essence, the difficulty seems to be in requiring that the $f_N$ be "normalized" as well as possess a dominating function.  If this method is feasible, at least it seems to require a bit of analysis to show the desired series all converge.  Perhaps I am missing something cleaner.  If so, a simpler solution would be much appreciated.    -Thanks. I've noticed this issue on a handful of other communities, but making the browser window narrow (mine is 1080x960) makes the .post-layout and #sidebar elements overlap. Maybe something to do with the grid CSS? The #mainbar element seems to be the correct width and changing the .post-layout's overflow-x to auto seems to "fix" it  From retrocomputing:    From this post, because we are meta after all:    Specs:   Google Chrome Version 78.0.3904.108 (Official Build) (64-bit) Ubuntu 18.04.3 LTS I've shown the existence of unique square roots of all positive rational numbers, so now I want to prove that the square root is monotone:   $0&lt;a&lt;b$ if and only if $\sqrt{a} &lt; \sqrt{b}$ Cannot create an array of LinkedLists in Java...? Quantum entanglement faster than speed of light? After looking into the different OAuth types and reading , I'm still confused on the specific pros and cons of user-agent vs web server flows.  The best explanation I can find says that user-agent tends to be used for mobile but it seems that they can both be used for desktop.   What makes it more appropriate to use one over the other in certain scenarios? Warn new users when they ask a question after a previous question is closed, downvoted, or deleted Another &quot;miséricorde&quot;:  Consider  (emphasis added):  I think its okay, please dont take any efforts for me. I personally do not feel the system helps ask good questions. I dont know why asking for a software in this case is bad. Basically I needed a command that would give me this data. There is no other way I could have asked the question. I could have changed the question just for the sake of changing. I feel I am better off elsewhere. Thanks for your very very prompt responses. Regards. Bye. – user1744649  We just lost another user due to inadequate guidance on what questions are allowed.  The  by the time they are banned has been proven incorrect. Given that , we need a better way to make sure that users can understand how to ask good questions and what types of questions are allowed. I suggest that we warn newcomers, in a clear but positive tone, when one of their questions has been closed, downvoted (to a score of -2 or lower), or deleted, so that they don't repeat the same mistake.  This is probably best done the next time the user asks a question, and should appear as an &quot;interstitial&quot; page prior to reaching the actual Ask Question form.  The page should not appear to users:  with at least 50 (or perhaps 75 or 100) reputation that have asked a good question since the last downvoted/closed/deleted question that have fixed a bad question and had it reopened/undeleted/upvoted.  The content of the page should be adapted based on the specific problem with the previous question.  I would imagine something similar to the following (example for a question closed as off topic on Super User):  Before you ask another question... One or more of your previous questions have been closed as off topic. The scope of on-topic questions is defined in the , as follows:  What kind of questions can I ask here? Super User is for computer enthusiasts and power users. If you have a question about …  computer hardware, computer software, or personal and home computer networking  and it is not about …  programming and software development, video games or consoles, websites or web services like Facebook, Twitter, and WordPress, electronic devices, media players, cell phones or smart phones, except insofar as they interface with your computer, issues specific to corporate IT support and networks, asking for a shopping or product recommendation,  … then you’re in the right place to ask your question!  Please make sure that the question you are about to ask is on topic as described above. If you need help determining whether your question can be asked on this site, you can ask for advice on  or . You may also want to edit your previous question to address any problems associated with it. To ensure a high standard of content quality and prevent disruption to the community, users who repeatedly post low-quality questions  Continue  The  doesn't address this issue as it is shown only to users with 10 reputation or less (rather than up to 50 and possibly higher) and does not address the specific problem with previous low-quality questions.  The point of this feature request is to provide a easily understood targeted message that actually teaches the user about what happened with the previous question he or she asked.  The EULA is generic and may not have conveyed the intended message clearly if the user still asked a low-quality or off-topic question. For reference,  currently has 143 reputation and the proposed message would probably have been shown after the first closed or deleted question. I know this can be a complex feature to implement, since it needs to be adaptive, but this should help eliminate confusion on what the rules are and minimize the incidence of good-faith users getting post-banned. What are the differences between Generics in C# and Java... and Templates in C++? I mostly use Java and generics are relatively new. I keep reading that Java made the wrong decision or that .NET has better implementations etc. etc.  So, what are the main differences between C++, C#, Java in generics? Pros/cons of each? Why is a Hyperplane called a "Hyper"plane? I just had this curious question. In other fields, the word "hyper" is actually used to refer to something which is "over; beyond; above" as defined by Google. An example of such terms would be Hyperglycaemia, defined by Wikipedia as:     a condition in which an excessive amount of glucose circulates in the blood plasma.   Or Hypersonic, defined by Google as:     relating to speeds of more than five times the speed of sound.   So, my question is, what would be the motive to give a Hyperplane such a name when it is defined as :     a subspace of one dimension less than its ambient space Because of the Rule of Two, is/was Sidious the strongest Sith ever? The Sith Rule of Two says: One to embody power, one to crave it. It's like a survival of the fittest.   If the apprentice must kill the master to be the master, that usually means the apprentice is stronger than the master. If this chain went on for many years, does this mean Sidious was the strongest Sith ever, just by the transitive property? Insert missing dates within table I have a table with a column for ID, Date and Frequency of occurrence for that particular date and ID.  ID    date          Frequency 1     2014-05-18      5 1     2014-05-19      4 1     2014-05-20      25 2     2014-05-20      7 3     2014-05-18      4 3     2014-05-20      1 4     2014-05-18      6   I'm looking to insert the dates for each ID that aren't currently there (assuming that the date ranges from 2014-05-18 to 2014-05-20) and add a value of 0 in Frequency for those.  For example, you can see that  ID 1 has an observation for all three dates;  ID 2 is missing 2014-05-18 and 2014-05-19;   ID 3 is missing 2014-05-19;   ID 4 is missing 2014-05-19 and 2014-05-20.  Therefore, the output should look like this  ID    date          Frequency 1     2014-05-18      5 1     2014-05-19      4 1     2014-05-20      25 2     2014-05-18      0 2     2014-05-19      0 2     2014-05-20      7 3     2014-05-18      4 3     2014-05-19      0 3     2014-05-20      1 4     2014-05-18      6 4     2014-05-19      0 4     2014-05-20      0   I've attempted the following from . However, that will only add dates with 0 Frequency that aren't present throughout the entire table instead of on an ID level.   DECLARE @s DATE = '20140518', @e DATE = '20140520';  SELECT c.date, Frequency = COALESCE(a.Frequency,0) FROM dbo.Calendar AS c LEFT OUTER JOIN dbo.table AS a ON c.date = s.[date] WHERE c.d &gt;= @s AND c.d &lt; DATEADD(DAY, 1, @e); $f(x)f(1/x)=f(x)+f(1/x)$ Find a function $f(x)$ such that:  $$f(x)f(1/x)=f(x)+f(1/x)$$  with $f(4)=65$.  I have tried to let $f(x)$ be a general polynomial: $$a_0+a_1x+a_2x^2+\ldots a_nx^n$$  which leaves $f(1/x)$ as:  $$a_0+a_1{1\over x}+a_2{1\over x^2}+\ldots + a_n{1\over x^n}$$  On comparing the coefficients of both sides, we see that:  $$2a_0=(a_0)^2+(a_1)^2+(a_2)^2+\ldots+(a_n)^2$$  And  $$a_1=(a_0a_1)+(a_1a_2)+ \ldots +(a_{n-1}a_n)$$  I don't know how to proceed further. I know I need to compare coefficients and come to a conclusion based on their values, but I don't see what to do next. What does "calculus" mean? "calculus" and "formal system"  From      a calculus is a formal system that consists of          a set of syntactic expressions (well-formed formulæ or wffs),    a distinguished subset of these expressions (axioms), plus    a set of formal rules that define a specific binary relation on the space of expressions.      From      Formal systems in mathematics consist of the following elements:         A finite set of symbols (i.e. the alphabet), that can be used for constructing formulas (i.e. finite strings of symbols).   A grammar, which tells how well-formed formulas (abbreviated wff) are constructed out of the symbols in the alphabet. It is   usually   required that there be a decision procedure for deciding whether a   formula is well formed or not.   A set of axioms or axiom schemata: each axiom must be a wff.   A set of inference rules.      what is the difference between a formal system, and a calculus, then? I think they are the same? "calculus" and "logic system"  "Calculus" appears in "propositional calculus" and "first-order predicate calculus", which are also called "propositional logic" and "first-order logic" respectively. So I thought "calculus" and "logic" mean the same, and "a logic" is, according to ,      A logical system or, for short, logic, is a formal system together with a form of semantics, usually in the form of model-theoretic   interpretation, which assigns truth values to sentences of the   formal language, that is, formulae that contain no free variables.    But then I saw "calculus" also appears in "lambda calculus", which is also a formal system. I think a lambda calculus isn't a logic system, right? What does "calculus" mean in "lambda calculus"? Furthermore  "calculus" can also mean computational real analysis for first-year college students.   Thanks. How do I clean the inside of my viewfinder? My viewfinder (not LCD) has spots of dust on it.  What is the best way to clean the inside?  I have cleaned the outside with a QTip. Subgroups of finite abelian groups. For every subgroup $H$ of a finite abelian group $G,$ there exists a subgroup $N$ of $G$ such that $G/N \cong H.$ I need to prove this or give a counter example.  I am aware of isomorphism theorems and classification of abelian groups, direct products etc. How to do volumetric lighting for a forest scene? Ctrl -C, Ctrl -V not working in different keyboard layout When I am in English, Ctrl+C, Ctrl+V works fine when I need to copy paste. But when I turn to Greek, Ctrl+C and Ctrl+V and basically no shortcut almost works in Greek.  So each time I have to alt shift and go back to English in order to user Ctrl+C to copy something. How can I apply this to the Greek keyboard profile?  EDIT  I also realized that when using NetBeans IDE 7.4,  I can copy and paste in Greek but I can't use the tonic system of the language over the words. In Aptana studio I can't use Copy and paste Ctrl+C, Ctrl+V When using gedit everything works fine. Different software use different keyboard layout settings? What is the difference between UNION and UNION ALL? What is the difference between UNION and UNION ALL?