According to the Skyrim Wiki, "daggers are silent, meaning that enemies are not alerted to your dagger swings, even missed ones." However,  there is generally a sound (grunt or guttural throat noise) to go along with a power attack animation.

Is this noise just for effect (like the passive spell-in-hand glow) or is the sound audible by potential victims/enemies?


Question: php scripts run only after renaming
Answer: This sounds a lot like a permissions issue.  When you save the "second" file, you're saving it with permissions 0644 by default, with your user/group, at least on *nix.  If you want, post the the output of ls -l file1 file2 before you do the rename, and I can give you a better answer.

As for permissions, try changing the permissions on the original file by using chmod:

chmod 0644 &lt;file&gt;