Read the text file with readlines (or my readfile function).
Then you can use contains to determine which line contains the text 'temp'. The code below can then be used to write the lines with and without this text.
fprintf(fid1,'%s\n',str{L});
fprintf(fid2,'%s\n',str{~L});
Edit:
To give a more complete code:
filename1='original_file.txt';
filename2='temp_file.txt';
str=cellstr(readlines(filename1));
L=contains(str,'temp');
fid1=fopen(filename1,'w');
fid2=fopen(filename2,'w');
fprintf(fid1,'%s\n',str{L});
fprintf(fid2,'%s\n',str{~L});
fclose(fid1);fclose(fid2);
