You can write text to a file using writelines() or by using fopen() / fprintf() / fclose(), or by using fopen() / fwrite() / fclose()
str = "case 'newcase', x = 5;"
writelines(str, 'testscript.m');
dbtype testscript.m
If you are wanting to write text into the middle of an existing file then unfortunately it gets a little more complicated.
