An easier way to search and replace in UNIX with perl
(taken from [[http://www.shooter.net/index.php/weblog/Item/an-easier-way-to-search-and-replace-in-unix-with-perl/]])

  perl -pi -e 's/search/replace/g' *.text

Here's a breakdown of how that command works:

''-p'' Assumes an input loop around the script. It reads each line of the file and outputs it after processing

''-i'' Activates in place editing of files

''-e'' Indicates a single lines script

''s/search/replace/g'' is the script or command. In this case it's a search and replace regex (regular expression). Replace the "search" and "replace" with the text to be operated upon.

*.text the filename(s) to operate on

You can also say

  perl -pi.bak -e 's/search/replace/g' *.text

The ''.bak'' tells it to save unchanged copies with that extension.
=====Searching and replacing directory paths with slashes=====
Often one will search and replace a directory path which itself contains forwards slashes. This link explains how to do so within a regex:

http://www.coderetard.com/2008/11/11/sed-how-to-escape-forward-slash-with-the-right-delimiter/

The summary is:

 In the regular expression, it’s not necessary to delimit the find and replace texts and search options with the slash ‘/’ character. In fact, you can use just about any character to delimit the expression:

  % sed s#file:\/\/#http:\/\/#g *.txt 
  % sed s@file:\/\/@http:\/\/@g *.txt 
  % sed sAfile:\/\/Ahttp:\/\/Ag *.txt

Using #, @, and A as the delimiter will all work out to the same valid sed operation to find all strings of "file://" text and replace it with "http://" text.