regexp

Replace uses PCRE via ReReplace.com to perform
find/replace routines on text.  Most useful for testing
regular expressions or searching through a text document
without the need for additional software.

Example:
regexp -f buy -r bye -t say buy -a replace
  Replace "buy" with "bye" in "say buy"
regexp -f reg(?:ular)? ?exp?(?:ression)?s? -t regex regular expressions regexp
  Highlight the various names for regular expressions

To use it, use the following switches:
-f
  Search string (needle)
-r
  Replacement string
-t
  Text to Search (haystack)
-a
  Action to perform. One of "find" "replace" or "preview".
  Find will hilight matches, preview will perform a replacement
  and highlight the changes, Replace will perform the find/replace
  and return the results in an easy to copy text area.
  Default action is "find"

Optionally, you can change the options using the -o switch
-o
  Options, are as follows
  o Regex mode (enable regex in find/replac)
  s dot matches new line
  i case insensitive
  m ^$ match at line breaks
  p Soft-wrap text on screen (disable preformatted)
  b highlight backreferences within matches
Options should be combined into a single expression,
Example: -o sim
Default options are -o impob.