tnb = tempname();
tn1 = tnb + "1.m";
tn2 = tnb + "2.m";
[fid1, msg] = fopen(tn1, 'w');
if fid1 < 0; error('was not able to write to temporary file "%s" because "%s"', tn1, msg); end
cleanMe1 = onCleanup(@() delete(tn1));
fprintf(fid1, '%%comment 1\n%%comment 2\n1 2 3\n4 5 6\n');
fclose(fid1)
fprintf('contents of first file\n=====\n')
type(tn1)
fprintf('\n=====\n');
[fid1, msg] = fopen(tn1, 'r');
if fid1 < 0; error('was not able to reopen temporary file "%s" for reading because "%s"', tn1, msg); end
[fid2, msg] = fopen(tn2, 'w');
if fid2 < 0; error('was not able to write to temporary file "%s" because "%s"', tn2, msg); end
cleanMe2 = onCleanup(@() delete(tn2));
while true
line_in = fgetl(fid1);
if ~ischar(line_in); break; end %end of file
fprintf(fid2, '%s\n', line_in);
end
fclose(fid1);
fclose(fid2);
fprintf('contents of second file\n=====\n')
type(tn2)
fprintf('\n=====\n');
Remember that when you fprintf() and you put literal text into the format string, that you need to put two % for each % character that you want to output -- so for example where I wanted %comment to be output I had to write %%comment in the format string. This is because %comment would have be interpreted as the format string %c (write the next parameter as a character) followed by 'omment' . % is the format specification for fprintf.
That was when I used
fprintf(fid1, '%%comment 1\n%%comment 2\n1 2 3\n4 5 6\n');
to output. The better way would have been to use
fprintf(fid1, '%s\n%s\n%s\n%s\n', '%comment 1', '%comment 2', '1 2 3', '4 5 6');
Now the % in the %comment part, is data and not part of the format specification -- the format specification is the %s
