What I do to achieve this is to make a visual rectangular selection with Ctrl-V at the place where I want to add the prefix, and once all lines are selected, just press I (that's a capital i) and type in the text. When exiting insert mode the text will be copied to all the lines.

What I do to achieve this is to make a visual rectangular selection with Ctrl-V at the place where I want to add the prefix, and once all lines are selected, just press I (that's a capital i) and type in the text. When exiting insert mode the text will be copied to all the lines.

This is the sequence in images:

• Visual selection of the place of insertion

• Type in the text

• Back to normal mode and the insertion is done

Note that this works anywhere, not only at the beginning of the line.