Sarep is a command-line search and replace tool written in Perl. It
supports regular expressions, case insensitivity/sensitivity, multiple
file search-and-replace, wildcards, writing out to a new file (rather than
overwriting the modified file), proper handling of metacharacters, reading
search/replace string from a file, and silent/verbose modes. 

WWW: http://tarp.worldserve.net/software/sarep.html