PHP - How to do a string replace in a very large number of files?

Question

I have two million text files in a server online accesible to internet users. I was asked to make a change (a string replace operation) to these files as soon as possible. I was thinking about doing a str_replace on every text file on the server. However, I don't want to tie up the server and make it unreachable by internet users.

Do you think the following is a good idea?

<?php

ini_set('max_execution_time', 1000);


$path=realpath('/dir/');
$objects = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path), RecursiveIteratorIterator::SELF_FIRST);
foreach($objects as $name => $object){
   set_time_limit(100);
  //do str_replace stuff on the file
}

Answer 1

Use find, xargs and sed from shell, i.e.:

cd /dir

find . -type f -print0 | xargs -0 sed -i 's/OLD/NEW/g

Will search all files recursively (hidden also) inside the current dir and replace OLD for NEW using sed.

---

Why -print0?

From man find:

If you are piping the output of find into another program and there is the faintest possibility that the files which you are searching for might contain a newline, then you should seriously consider using the '-print0' option instead of '-print'.

---

Why xargs ?

From man find:

The specified command is run once for each matched file.

That is, if there are 2000 files in /dir, then find ... -exec ... will result in 2000 invocations of sed; whereas find ... | xargs ... will only invoke sed once or twice.