You might notice that the below is not a nice little 3 or 5 line program. That is because the operating systems that MATLAB is supported on do not offer any method of deleting bytes in the middle of a file. The only real option is to copy the wanted text to another file and rename the files around.
Some of what is in this code is error checking and making sure that there is always an intact version of the file. If something goes wrong, you don't want to end up with a corrupted file. Always keep a backup version until you know the the deletion did what you wanted (and only what you wanted)
first_line_to_delete = 3;
num_lines_to_delete = 1;
infilename = 'YourFile.txt';
[pathstr, file, ext] = fileparts(infilename);
backfile = fullfile(pathstr, [file '.bak']);
if strcmp(infilename, backfile)
error('I refuse to edit a backup file! Nothing has been changed.');
end
outfile = tempfile; %a temporary file in TMP directory
fin = fopen(infilename, 'r');
if fin < 0; error('Input file does not exist'); end
fout = fopen(tfile, 'w');
if fout < 0
fclose(fin);
error('Could not open temporary output file');
end
%read lines before the one to be deleted and write them to output
for K = 1 : first_line_to_delete - 1;
inline = fgets(fin);
if ~ischar(inline); break; end; %end of file?
fwrite(fout, inline);
end
for K = 1 : num_lines_to_delete
if ~ischar(inline); break; end %in case EOF
inline = fgets(fin); %and do nothing with it
end
%copy all remaining input lines to output file
while ischar(inline)
inline = fgets(fin);
if ischar(inline) %not if we hit EOF
fwrite(fout, inline);
end
end
fclose(fin);
fclose(fout);
%M'Kay, we did the copying and have a file with the desired
%result. Now put it in the proper place
status = movefile(infilename, backfile);
if ~status
if strcmp(infilename, backfile)
fprintf(2, 'Good thing your programmer is paranoid about people overriding\nsanity checks, because something went wrong and you nearly lost your file!\n');
else
delete(backfile);
end
error('Could not rename file to .bak, file left untouched');
else
status = movefile(outfile, infilename);
if ~status
error( ['Could not rename temp file to original name, original moved to ', backfile]);
end
end
