MATLAB: How to read data from a file into cell array keeping indents undisturbed

fopenfprintfMATLABread datasimulinktextscanwrite data

I am trying to read a data from a file, modify it and write to a same file which I did using, 
fid  = fopen('file.ext','r');
fclose(fid);
lines = textscan(fid,'%s','Delimiter','\n');
...
fid  = fopen('file.ext','w');
for row = 1:length(lines{1})
    fprintf(fid,'%s\n',lines{1}{row});
end
fclose(fid);
But I could not reproduce the indents which were in the original file. So any suggestions to achieve this and make the above process easier?
Note: the file extension is not .txt but similar to text format. The data which I try to read has html tag elements and attributes.
I would also like to know whether there is any way to directly modify a file without reading it?
Thanks in advance!

Best Answer

% Import file:
Str = fileread('file.ext');
% Remove trailing line break to avoid appending an additional empty line:
if ~isempty(Str) && Str(numel(Str)) == char(10)
    Str(numel(Str)) = [];
end
% Split lines:
% lines = strsplit(Str, char(10));
% Faster but uglier (this is what happens inside STRSPLIT):
lines = regexp(Str, ['(?:', char(10), ')+'], 'split');
...
% Write output:
fid = fopen('file.ext', 'w');
fprintf(fid, '%s\n', lines{:});
fclose(fid);
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