How do I join two lines in vi?

Question

I have two lines in a text file like below:

S_F
_ID_T_O.DAT
         


        

Answer 1

Vi or Vim?

Anyway, the following command works for Vim in 'nocompatible' mode. That is, I suppose, almost pure vi.

:join!

If you want to do it from normal command use

gJ

With 'gJ' you join lines as is -- without adding or removing whitespaces:

S_F
_ID_T_O.DAT

Result:

S_F_ID_T_O.DAT

With 'J' command you will have:

S_F _ID_T_O.DAT

Note space between type> and _ID.