In addition to flipping permission bits on and off, we can also reset them altogether. By using the = operator, we can tell chmod that we want the specified permissions and no others:

$ chmod =rx scriptfile.sh

Above, we just set all "read" and "execute" bits, and unset all "write" bits. If you just want to reset a particular triplet, you can specify the symbolic name for the triplet before the = as follows:

$ chmod u=rx scriptfile.sh