subtend

sed - is useful to find and replace text in single multiple files.

    * Replacing foo with foo_bar in a single file.

      sed -i 's/foo/foo_bar/g' somefile.module
          o -i = tell sed to edit the file(s)
          o s = substitute the following text
          o foo = what you want to substitute
          o foo_bar = what you want to replace
          o g = global, match all occurrences in the line

# Replacing foo with foo_bar in a multiple files.

sed -i 's/foo/foo_bar/g'  *.module 

##
# recursive find/replace
#
find . -type f -print0 | xargs -0 sed -i 's/foo/bar/g'