Did you see the help for fgetl()? Just modify it to add an array for the first characters of the lines:
fid = fopen('fgetl.m');
tline = fgetl(fid);
lineNumber = 1;
while ischar(tline)
disp(tline)
firstCharacters(lineNumber) = tline(1);
tline = fgetl(fid);
lineNumber = lineNumber + 1;
end
fclose(fid);
