search-and-replace
Search-and-replace is a capability that allows a computer user to find a given sequence of character s in one or more text file s and, if desired, replace the sequence with another sequence of characters. A global search-and-replace means that the replace is to take effect in all files within the context of the search.
In UNIX and some other operating systems, a grep command or utility can be used to do search-and-replace. In Windows operating systems, a popular product that provides a graphical user interface is called Search and Replace for Windows 95/NT.