Hello,
You should be able to modify only columns 16 to 25 of that specific line with the following,
fd = fopen('yourfile'); % open file
yourtext = textscan(fd,'%s','Delimiter','\n'); % read lines into cell array
yourtext = yourtext{1}; % fix cell array to be nx1 rather than a 1x1 containing the nx1
yourtext{line} = [yourtext{line}(1:15) 'this will replace 16 to 25' yourtext{line}(26:end)]; % change line
fclose(fd); % close file
You can do this in many ways, such as by finding the line with regexp, but the above is fine if you know the line number.
Also, if you want to write the edited file back to the file,
fd = fopen('yourfile','w'); % open and clear content from file
fprintf(fd,'%s\n',yourtext{:}); % write strings in yourtext to file
fclose(fd); % close file
This will delete the contents of the file and replace them with the strings in yourtext, which should produce the same file with the edited text (wouldn't hurt to save a backup).
Hope this helps!
