Enter data display options

[nadavWeisler]

Commands:

1. colnames - display all column names.
2. head - show the first 5 rows.
3. describe <column_name> - display column name, type.
   For numeric: mean, sd, max value, and min value.
   For string: count of unique values
4. Unique <column_name> - Display all the unique values of the column