You should think seriously about what happens if your server crashes whilst processing lines 38 through 44 of your script.
At that point you have opened the file, read the contents, closed and re-opened the file for output. If the server crashes, or even just the process gets interrupted, you have blown away the disc copy of the file and only retain its contents in memory. Even assuming you have backups, trying to work out which script were correctly modified, which ones have yet to be modified and which one was in the process of being modified when the interuption occurs can be extremely tiresome.
Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller