Vim has some really useful commands, especially search and replace ones. Unfortunately I'm always forgetting the finer details of how to use them so here's an example:

To break down whats happening above:

• : switches Vim into command mode
• % means we're going to apply this command to every line in our file
• s means we're using the substitute command. The format of the command is s/search/replacement, 'search' can be a regular expression
• $ tells vim to search for the end of the line
• \rthis is a new line tells vim to replace with a new line character, and to put the text "this is a new line" on that line.

NOTE: \r is used as the new line character when vim is using DOS file format, to find out which file format you are using type :set ff? You can find out more about Vim file formats here.

#Pete Graham