How to create a text file from grep output

I have a data file which looks like this:

Input

 x    y    z  coulomb normal shear
(km) (km) (km) (bar)  (bar)  (bar)
 -30  -30  2.5  0.0    0.0    0.0
 -30  -29  2.5  0.1    0.1    0.1

I would like to remove the first three lines, so I just have a file full of numbers, and then create a new file with this data. If I was working in Unix, the command would be as follows:

grep -v -e Input -e x -e (km) filename.txt > newfilename.txt

Matlab has a grep function, but I can't work out how to generate a new file with the output from grep.

Answer 1

[Guillaume]

Matlab does not have a grep function (according to my docs). It's a fairly simple function to write anyway:

function skipcopy(origfile, newfile, skip)
   %origfile: full path of file to crop
   %newfile: full path of cropped file to create
   %skip: number of initial line to skip:

     fidin = fopen(origfile, 'rt');
     if fidin == -1
        error('failed to open %s', origfile);
     end
     fidout = fopen(newfile, 'wt');
     if fidout == -1
        error('failed to create %s', newfile);
     end
     for s = 1:skip
        fgetl(fidin);
     end
     fwrite(fidout, fread(fidin));
  end

Answer 2

[dpb]

If that's the way you're intent on going about it, just use the bang operator "!" and submit the command to the OS. There are Windows grep's easily available.

But, in Matlab it's simpler to just use the i/o functions imo...

x=importdata('filename.txt');  % it'll find the header on it's own and return the numeric
dlmwrite('aknew.dat',x(1:5,:),'delimiter',' ','precision','%.2f') % write with 2 decimals

If you must have the precision as shown then need to use format string and fprintf