Open last closed file in a new tab in Vim

You don't necessarily have to leave normal mode to open the alternate buffer in a new window:

CTRL-W ^ opens the alternate buffer in a horizontal split.

CTRL-W T opens the current buffer in a new tab (Shift-T, that is).

So, one solution to your title question is the following combo.

CTRL-W ^, CTRL-W T: opens the alternate buffer in a new tab.

Note that for the caret "^" in the first command you don't have to release the Control key and you don't have to press Shift, just hold down CTRL then strike W and 6 (where the caret is located on many English keyboard layouts).

# is simply an Ex special character that will be replaced with the name of the alternate file. Do an :ls, and the alternate file will be marked with a # there also.

# can similarly be used with :tabnew and split. In the examples below I'll use :tabe in place of :tabnew as :tabe is a shorter alias for :tabnew (search for either in the help docs):

• To open the alternate file in a new tab: :tabe#
• To open the file in a new split: :split#; this can be abbreviated to :sp#, and :vsp# for a vertical split.

Using a buffer number from :ls, e.g. buffer number 5 you can also:

• open the buffer in a split with :sp#5; alternately :sb5 if the switchbuf option contains the newtab specifier - see :help switchbuf
• open the buffer in a vertical split with :vsp #5 (there is no :vsb)
• open the buffer in a new tab with :tabe #5