dig v2
3 in phr dig you later: Used as a salutation in parting.
1940 in 1983 Taft Blues Lyric Poetry 23/2, Going to tell you baby: like the farmer told his potato / I’m going to plant you now woman: but I will dig you later. 1970DARE (Qu. NN11, Informal ways of saying ‘good-bye’ to people you know quite well)Inf PA247, Dig you later. [Inf Black] 1970 Major Dict. Afro-Amer. Slang 46, Dig you later: (1930’s and after) an expression of farewell; it was shortened to “later.”