Many ex commands that perform normal editing operations have an equivalent in vi that does the job more simply. Obviously, you will use dw or dd to delete a single word or line rather than using the delete command in ex. However, when you want to make changes that affect numerous lines, you will find the ex commands more useful. They allow you to modify large blocks of text with a single command.
These ex commands are listed below, along with abbreviations for those commands. Remember that in vi each ex command must be preceded with a colon. You can use the full command name or the abbreviation, whichever is easier to remember.
|t||Copy lines (a synonym for co).|
You can separate the different elements of an ex command with spaces, if you find the command easier to read that way. For example, you can separate line addresses, patterns, and commands in this way. You cannot, however, use a space as a separator inside a pattern or at the end of a substitute command.
For each ex editing command, you have to tell ex which line number(s) to edit. And for the ex move and copy commands, you also need to tell ex where to move or copy the text to.
You can specify line addresses in several ways:
With explicit line numbers
With symbols that help you specify line numbers relative to your current position in the file
With search patterns as addresses that identify the lines to be affected ...