Visual + Ex Range

Pressing : from Visual auto-fills the range.

Keys: :

When you press : while in visual mode, Vim drops you to the command line with :'<,'> already typed โ€” the range covering the selection. Just type your command after.

Visual mode and Ex commands plug right into each other. Press : from any Visual selection and Vim pre-types the range.

From Visual to substitute
KeyNote
{key:V}visual-line mode
{key:5}{key:j}Extend down 5 lines
{key::}Vim shows :'<,'>
`s/foo/bar/g`Operate on those lines only

Watch

See also: Ex Ranges, Substitute (:s), Special Marks