In julia `tail(DataFrame)` show tail not defined

The head and tail function have been removed a long time ago. You are looking for last(data, n) where n is the number of rows you want to display.

julia> using DataFrames

julia> df = DataFrame(rand(100, 3), :auto);

julia> last(df, 3)
3×3 DataFrame
 Row │ x1        x2        x3       
     │ Float64   Float64   Float64  
─────┼──────────────────────────────
   1 │ 0.26611   0.17931   0.242719
   2 │ 0.059735  0.108221  0.882079
   3 │ 0.779656  0.112243  0.314842

If you want to know more about this, here's a post from Bogumil Kaminski who is one of the lead developers of DataFrames:

https://bkamins.github.io/julialang/2021/05/14/nrow.html