Copy indent from current line when starting a new line (typing in Insert mode or when using the "o" or "O" command). If you do not type anything on the new line except or CTRL-D and then type , CTRL-O or , the indent is deleted again. Moving the cursor to another line has the same effect, unless the 'I' flag is included in 'cpoptions'. When autoindent is on, formatting (with the "gq" command or when you reach 'textwidth' in Insert mode) uses the indentation of the first line. When 'smartindent' or 'cindent' is on the indent is changed in a different way. The 'autoindent' option is reset when the 'paste' option is set and restored when 'paste' is reset.