To play Blackjack as an “always-stander” run the following command:
yes stand | blackjack -n1e5 --flat_bet=1 --no_insurance=true > /dev/null
The UNIX command
yes stand writes the string “stand” repeteadly to the standard output, which is piped to the executable
blackjack (assumed to be installed system-wide). The arguments tell Libre Blackjack to play one hundred thousand hands (
-n1e5) using a flat bet and without asking for insurance if the dealer shows an ace (
no_insurance). As there is no
blackjack.conf file, the rules are—as expected—the default ones (see the documentation for details).
This example is only one-way (i.e. the player ignores what the dealer says) so it is better to redirect the standard output to
/dev/null to save execution time. The results are written as a YAML-formatted data to
stderr by default once the hands are over, so they will show up in the terminal nevertheless. This format is human-friendly (far more than JSON) so it can be easily parsed, but it also allows complex objects to be represented (arrays, lists, etc.).
--- result: "(-15.8 ± 0.9) %" mean: -0.157675 error: 0.00940803 hands: 100000 bankroll: -15767.5 bustsPlayer: 0 bustsDealer: 0.27344 wins: 0.38585 pushes: 0.04807 losses: 0.56608 ...
Exercise: verify that the analytical probability of getting a natural playing with a single deck (for both the dealer and the player) is 32/663 = 0.04826546…