I have many processes running on my Ubuntu. One day later, I find that one file has been changed. Now I want to know which process touched my file.  What can I do? (I can not modify the running processes)
Three files have suddenly appeared in my home directory, called "client_state.xml", "lockfile", and "time_stats_log". The last two are empty. I'm wondering how they got there. It's not the first time it has happened, but the last time was weeks ago; I deleted the files and nothing broke or complained. I haven't been able to think of what I was doing at the time reported by stat $filename. Is there any way I can find out where they came from?  Alternatively, is there a way to monitor the home directory (but not sub-directories) for the creation of files?
Resetting Ubuntu to factory settings I've had a lot of problems lately and now I'm having problems logging in at the login screen. I'm giving up and just want to reset and start over. How can I "factory reset" Ubuntu, in this situation, or, for future reference, in general? How can I change the class of an HTML element in response to an onclick or any other events using JavaScript? This is a "catch-all" question designed to serve as an answer for all questions about choosing web hosting.  Pro Webmasters no longer accepts new questions about how to choose hosting.  All future questions pertaining to finding web hosting should be closed as a duplicate of this question. For more information about this policy please see .    How to find web hosting that meets my requirements?  What we're looking for in answers to this question are the basics about web hosting:   What is web hosting? What is the difference between shared, VPS, and dedicated hosting? How does a content delivery network relate to web hosting? Anything else you feel is helpful in finding a web host.   What we do not want is:   Endorsements or recommendations for specific web hosts We do not want your experience or other subjective information (just the facts please) Replacing non-English characters in attribute tables using ArcPy and Python? I have a few shapefiles where some of the attributes contain the non-English characters ÅÄÖ. Since some queries doesn't work with these characters (specifically ), I tried to change them in advance with a simple script and add the new strings to another field.  However, change in characters works fine but not updating the field with arcpy.UpdateCursor.   What is an appropriate way of solving this?  I have also tried to do this via the Field Calculator while posting "code" to the codeblock, with the same error.  Error message: Runtime error  Traceback (most recent call last):   File "", line 1, in    File "c:/gis/python/teststring.py", line 28, in      val = code(str(prow.Typkod)) UnicodeEncodeError: 'ascii' codec can't encode character u'\xc4' in position 3: ordinal not in range(128)  Code:  # -*- coding: cp1252 -*- def code(infield):     data = ''     for i in infield: ##        print i         if i == 'Ä':             data = data + 'AE'         elif i == 'ä':             data = data + 'ae'         elif i == 'Å':             data = data + 'AA'         elif i == 'å':             data = data + 'aa'         elif i == 'Ö':             data = data + 'OE'         elif i == 'ö':             data = data + 'oe'         else:             data = data + i     return data   shp = r'O:\XXX\250000\DB\ArcView\shape.shp'  prows = arcpy.UpdateCursor(shp)  for prow in prows:     val = code(unicode(str(prow.Typkod), "utf-8"))     prow.Typkod_U = val     print val     prows.updateRow(prow)   The values of Typkod are of the type: [D, D, S, DDRÄ, TRÄ] etc.  I use ArcMap Basic (10.1) on Windows 7.    New Error message:  Runtime error  Traceback (most recent call last):   File "", line 1, in    File "c:/gis/python/teststring.py", line 29, in      val = code(unicode(str(row.Typkod), "utf-8")) UnicodeEncodeError: 'ascii' codec can't encode character u'\xc4' in position 3: ordinal not in range(128)  &gt;&gt;&gt; val 'DDRÄ' &gt;&gt;&gt; type(val) type 'str'      It appears as if the output from the function is wrong somehow. When there's ÅÄÖ involved it returns data = u'DDR\xc4' and not (as was my intention) data = 'DDRAE'. Any suggestions on what might cause this? $\textit{Why}$ the cases in 4 $\nmid n^2 - 3?$ (bases cases in modular induction) This question has already been answered . My question is, when we suppose the hypothesis is not true (proof by contradiction), namely that $4 \mid (n^2 - 3)$, we get $n^2 - 3 = 4k$ for some integer $k$ and then we have two cases. But where does the two cases come from? In addition, why does putting them into two cases work to prove the statment? My thought process would be to try to prove this statement by contradiction and somehow figure out a way to produce a contradiction similar to how $\sqrt{2}$ is proved by contradiction. Any help is great! Let me know if I need to clarify more! How to remove conference information from the ACM 2017 SIGCONF template? Duplicate explanation should encourage improvement of original How to remove Home Folder icon from desktop in Ubuntu 20.04? When I start Ubuntu I had my &quot;home/user&quot; in my Desktop. test is my User.   How do I make the folder not be on the desktop? Received an email intended for another person I'm not really sure how email routing works, but someone ordered something on Amazon and I received the email instead of them.  Or maybe we both got it, I don't know.  The order doesn't show up in my account, so I'm certain I wasn't charged for it, but I shouldn't be getting other peoples' emails.  We'll say that my email is johndoe1@gmail.com, and somebody who's email is john.doe1@gmail.com places an order on Amazon.  The confirmation email is sent to me at johndoe1@gmail.com.  I checked the email header, and it did say To: john.doe1@gmail.com which is not my email address.  At first I thought that Google ignores periods in email addresses, but I tested the account setup and it doesn't give any error when you put a period in the address.  I didn't create the account; I just used the "check availability" function and the address I chose with a period was fine.  Maybe someone with knowledge about how Email works could tell me why this happened.  Is this a bug in the way Amazon sends emails?  Or is it a bug in how Google receives them?  Who should I report this issue to? I've got some lenses of brand X, but I've just got a new camera of brand Y. How can I tell if it's possible to use my lenses on my camera? I accept that I may lose a lot of automatic functionality like autofocus, aperture control and metering when using an adapter to connect the two. Can newsletters take into account a user's ignored tags on that site? I have seen several questions that discuss using your "Favorite" tags to construct a newsletter.   I'm looking for a similar request - but for ignored tags.  I figure it might make sense to split this request from the "favorite" requests because it has different implementation.  Can we exclude questions on the "ignore" tags lists in the newsletter?   For example, I subscribe to the Board and Card Games newsletter.   Currently (and frequently) 6 of the 7 questions are about magic-the-gathering, a tag I have in my ignored list.     I now get a newsletter where at best 1/7 questions is interesting and worth clicking on.  Related questions about using "Favorites": What is the music on S3E16 when Todoroki was fighting group of ninjas? Why do we say "last night" and not "yesterday night"? As from object, is there a rational reason for saying "last night" rather than  "yesterday night", though you would say "yesterday morning" and "yesterday afternoon"? Why doesn't the "zig-zag" comb deformation retract onto a point, even though it's contractible? I am starting to read Hatcher's book on Algebraic Topology, and I am a little stuck with exercise 6(c) in Chapter $0$. Unfortunately a picture is involved so it doesn't quite make sense for me to repeat it here - but I'll do it anyways (maybe it helps)     Let $Z$ be the zigzag subspace of $Y$ homeomorphic to $\mathbb{R}$ indicated by the heavier line in the picture:       Show there is a deformation retraction in the weak sense of $Y$ onto $Z$, but no true deformation retraction."   Now the definition for deformation retraction and weak deformation retraction as as follows:  We say that $f: X \to X$ is a deformation retraction of a space $X$ onto a subspace $A \subset X$ if there exists a family of maps $f_t : X \to X$ with $t \in [0,1]$ such that $f_0 = \mathbb{1}$ (the identity) and $f_1 (X) = A$ and also $f_t$ restricts to the identity on $A$ for each $t$.   A weak deformation retraction is almost the same, only that we now relax the conditions $f_1(X) = A$ to $f_1 \subset A$ and, for each $t \in [0,1]$ we require that $f_t(A) \subset A$.  Hence, as far as I understand the question and the concepts involved, I need to show that basically no map can be constructed such that the bold zigzag - line stays put while the thin lines retract to the bold line over a finite time interval $0 \leq t \leq 1$. However, I should be able to show that I can pull the thin lines continously onto the thick line, provided I am allowed to move points on the zigzag line .. is that correct ?  Now, the problem is I can't see why I shouldn't be able to do the former, given that I could find a weak deformation retract. Any help would be great! Intuitive explanation for dividing by $n-1$ when calculating standard deviation? How do I enable or disable the global application menu? Change elements on different positions within a list How compute $\lim_{p\rightarrow 0} \|f\|_p$ in a probability space? Is there any rule for when it is better to use genitive case or noun as adjective? I'm not sure if there is any difference in meaning in this example:     The department of accounting       The accounting department   Can I also use both forms in situations like:     The restaurants of Paris / The Paris restaurants      The room window / The window of the room I already derived a QM expectation value for ordinary momentum which is: $$ \langle p \rangle=  \int\limits_{-\infty}^{\infty} \overline{\Psi}  \left(- i\hbar\frac{d}{dx}\right) \Psi \, d x $$ And I can read clearly that operator for momentum equals $\widehat{p}=- i\hbar\frac{d}{dx}$. Is there an easy way to derive an expectation value for $\langle p^2 \rangle$ and its QM operator $\widehat{p^2}$?