Using VI editor to replace text

To perform a global search and replace in vi, use the search and replace command in command mode:

:%s/search_string/replacement_string/g

The % is a shortcut that tells vi to search all lines of the file for search_string and change it to replacement_string. The global (g) flag at the end of the command tells vi to continue searching for other occurrences of search_string. To confirm each replacement, add the confirm (c) flag after the global flag.