Keep only the lines containing exact number of delimiters
Removal of lines with no more or fewer than 'N' fields?
How do I disable Bootchart? I dont want a Bootchart to be generated on every startup. How do I disable bootchart ?  Once disabled, how do I re-enable bootchart ?  I don't mean uninstall. How can I send an email using PHP? Soft version of the maximum function? In the book Deep Learning, it says the softmax function is de facto a soft argmax function, and the corresponding soft version of the maximum function is $$\text{softmax} (z)^T z$$ How to understand the latter? Definite integral, quotient of logarithm and polynomial: $I(\lambda)=\int_0^{\infty}\frac{\ln ^2x}{x^2+\lambda x+\lambda ^2}\text{d}x$ Why can't I suggest edits on SE meta sites? How to change keyboard layout in Lubuntu 15.10? I have recently upgraded my PC from Lubuntu 14.10 to 15.10. Before the upgrade my keyboard layout matched my Danish keyboard. But after the upgrade I probably have a standard English/US layout.   Preferences/Language Support, doesn't let me configure the keyboard layout. Preferences/Keyboard and Mouse, only let me configure stroking delay and similar.    I don't know about iBus and fcitx, as far as the tooltip infomation tells me, its for more complex languages such as Chinese.  I don't have a US icon in the taskbar, no keyboard and/or language icon at all.  Things I have tried:   Running the following in a terminal works, but only until the next reboot:  setxkbmap -layout dk  I got the following parameter in the file /etc/default/keyboard:  XKBLAYOUT="dk"  Installing and running the app Lxkeymap changes the keyboard to Danish when I run it, but rebooting will change the layout back to US.   I don't want anything fancy, I just want to set my keyboard layout to Danish. How can I do that? Abelian group (Commutative group) Prove that if in a group $(ab)^2= a^2 b^2$ then the group is commutative.  I am having a hard time doing this. Here is what I have so far: Proof:  $a^2 b^2= a^1 a^1 b^1 b^1$ =$aa^{-1}bb$ =ebb Hence,$aa^{-1}=e$  I am stuck, I do not know if this is the right process in proving this What is a virtual terminal for? Make a file pointer read/write to an in-memory location Creating image with specific latitude/longitude positions using GDAL? I have an ASCII file with latitude, longitude, and data_val in the following format.  35-13.643782N, 080-57.190157W, 118.6 ...   I have a GeoTiff image file, and I can easily view it.  I want to place a "pin" (can be a dot/flag/star or whatever is easiest) on the image at the specific latitude/longitude position found in the ASCII file.  Here is what I've managed to do so far:  My source image looks like this:  Driver: GTiff/GeoTIFF Files: /tmp/Charlotte SEC 100.tif Size is 16867, 12358 Coordinate System is: PROJCS["Lambert Conformal Conic",     GEOGCS["NAD83",         DATUM["North_American_Datum_1983",             SPHEROID["GRS 1980",6378137,298.2572221010042,                 AUTHORITY["EPSG","7019"]],             AUTHORITY["EPSG","6269"]],         PRIMEM["Greenwich",0],         UNIT["degree",0.0174532925199433],         AUTHORITY["EPSG","4269"]],     PROJECTION["Lambert_Conformal_Conic_2SP"],     PARAMETER["standard_parallel_1",38.66666666666666],     PARAMETER["standard_parallel_2",33.33333333333334],     PARAMETER["latitude_of_origin",34.11666666666667],     PARAMETER["central_meridian",-78.75],     PARAMETER["false_easting",0],     PARAMETER["false_northing",0],     UNIT["metre",1,         AUTHORITY["EPSG","9001"]]] Origin = (-365041.822331817995291,240536.419747152860509) Pixel Size = (42.334586069440391,-42.334898968590878) Metadata:   AREA_OR_POINT=Area   TIFFTAG_DATETIME=2016:06:24 12:46:45   TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)   TIFFTAG_SOFTWARE=Adobe Photoshop CS5 Windows   TIFFTAG_XRESOLUTION=300   TIFFTAG_YRESOLUTION=300 Image Structure Metadata:   COMPRESSION=LZW   INTERLEAVE=BAND Corner Coordinates: Upper Left  ( -365041.822,  240536.420) ( 82d48'55.43"W, 36d13' 4.92"N) Lower Left  ( -365041.822, -282638.262) ( 82d35'10.11"W, 31d30'17.00"N) Upper Right (  349015.641,  240536.420) ( 74d51'46.40"W, 36d13'26.16"N) Lower Right (  349015.641, -282638.262) ( 75d 4'55.60"W, 31d30'36.99"N) Center      (   -8013.091,  -21050.921) ( 78d50'12.11"W, 33d55'36.35"N) Band 1 Block=16867x1 Type=Byte, ColorInterp=Palette   Color Table (RGB with 256 entries)     0: 255,255,255,255 ...   Here is what I've managed to cobble together in Python:  from osgeo import gdal, osr  src_filename = '/tmp/Charlotte SEC 100.tif' dst_filename = '/tmp/foo.tiff'  # Opens source dataset src_ds = gdal.Open(src_filename) format = "GTiff" driver = gdal.GetDriverByName(format)  # Open destination dataset dst_ds = driver.CreateCopy(dst_filename, src_ds, 0)  # Specify raster location through geotransform array # (upperleftx, scalex, skewx, upperlefty, skewy, scaley) # Scale = size of one pixel in units of raster projection # this example below assumes 100x100 gt = [-365041.822, 100, 0, 240536.420, 0, -100]  # Set location dst_ds.SetGeoTransform(gt)  # Get raster projection epsg = 4269            # http://spatialreference.org/ref/sr-org/lambert_conformal_conic_2sp/ srs = osr.SpatialReference() srs.ImportFromEPSG(epsg) dest_wkt = srs.ExportToWkt()  # Set projection dst_ds.SetProjection(dest_wkt)  # Close files dst_ds = None src_ds = None   But, I can't quite figure out how to place a "red dot" at 35-13.643782N, 080-57.190157W  I'm having to learn some new details here (nomenclature about GIS). The speed of light is the same in all inertial frames.  Does it change from a non-inertial frame to another? Can it be zero?  If it is not constant in non-inertial frames, is it still bounded from above? Safely turning a JSON string into an object Given a string of JSON data, how can I safely turn that string into a JavaScript object?  Obviously I can do this unsafely with something like:  var obj = eval("(" + json + ')');   but that leaves me vulnerable to the JSON string containing other code, which it seems very dangerous to simply eval. Is adjoint of singular matrix singular? What would be its rank? Let $A$ be a square and singular matrix of order $n$.  Is $\operatorname{adj}(A)$ necessarily singular? What would be the rank of $\operatorname{adj}(A)$? Is spacetime discrete or continuous? How to edit 'etc/hosts' file in non-rooted phone? I need to include code in the appendix of my thesis. The code contains comments and the compilation instantly breaks returning:  Unicode char �\lst@FillFixed@ (U+5A8) (inputenc)                not set up for use with LaTeX. l.160       if (lastArg &lt; 0, lastArg = 360°                                               + lastArg);   This is only one of many characters which produce problems. I cannot change my entire code just because this won't compile. Is there any way to include code with arbitrary unicode characters? Thank you.   Edit: complete sample code, as requested.  \RequirePackage[l2tabu,orthodox]{nag}   \documentclass[headsepline,footsepline,footinclude=false,oneside,fontsize=11pt,paper=a4,listof=totoc,bibliography=totoc]{scrbook} % one-sided   \usepackage[toc,page]{appendix} \usepackage{listings} \usepackage[utf8]{inputenc}  \lstset{     inputencoding=utf8,   extendedchars=true,   basicstyle=\footnotesize\ttfamily,   showstringspaces=false,   showspaces=false,   numbers=left,   numberstyle=\footnotesize,   numbersep=9pt,   tabsize=2,   breaklines=true,   showtabs=false,   captionpos=b,     literate={ö}{{\"o}}1 {ä}{{\"a}}1 {ü}{{\"u}}1  }  \begin{document}  \begin{appendices} \lstinputlisting{code/power_series.html} \end{appendices}  \end{document}   Relevant content of power_series.html:  if (lastArg &lt; 0, lastArg = 360° + lastArg);   There really is not much to say about this problem. I only want to be able to use all unicode characters inside a listing. Thank you. Is it okay to use the phrase "try and"? Is it grammatically correct? e.g. "I will try and answer ..." I read the following sentence in book (App).     I will try and answer any questions you ask.   Why don't they use the following? (it is much common):     I will try to answer any questions you ask.   Is there any difference in meaning?  Update:  I noticed that a lot of books and news websites are using this phrase:        Although Katty will try and answer as many questions as she can.    He puller would have a chance to try and answer the question on her own ... I have this strange problem with conky. It doesn't show properly on the desktop:    I've tried everything from editing conky widget file to reinstalling conky and conky manager (v.2.4). Who knows how to fix it? How do I add Headers in List of Tables page? How can I prove that every prime except 2 and 5 divide infinitely many of the following integers $11, 111, 1111, ...$ ?