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-
- ---
- title: Always stand
- ...
-
- # Always stand
-
- > Difficulty: 02/100
-
- To play Blackjack as an “always-stander” run the following command:
-
- ```terminal
- yes stand | blackjack -n1e5 --flat_bet --no_insurance > /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 (`flat_bet`, it defaults to a unit bet in each hand) 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).
-
- The `/dev/null` part is important, otherwise Libre Blackjack will think that there is a human at the other side of the table and will
-
- 1. run slower (it will add explicit time delays to mimic an actual human dealer), and
- 2. give all the details of the dealt hands in the terminal as ASCII (actually UTF-8) art
-
- 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](http://yaml.org/)-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.).
-
-
- ```yaml
- ---
- rules:
- decks: 6
- hands: 100000
- hit_soft_17: 1
- double_after_split: 1
- blackjack_pays: 1.5
- rng_seed: -2067081387
- number_of_burnt_cards: 0
- no_negative_bankroll: 0
- max_bet: 0
- penetration: 0.75
- penetration_sigma: 0.05
- cpu:
- user: 0.238384
- system: 0.226465
- wall: 0.462519
- second_per_hand: 4.6e-06
- hands_per_second: 2.2e+05
- player:
- wins: 0.38547
- pushes: 0.04744
- losses: 0.56709
- dealer_blackjacks: 0.04749
- player_blackjacks: 0.04803
- dealer_busts: 0.27168
- player_busts: 0
- doubled_hands: 0
- doubled_wins: 0
- insured_hands: 0
- insured_wins: 0
- number_of_hands: 100000
- number_of_shuffles: 2070
- total_money_waged: 100000
- worst_bankroll: -15870.5
- final_bankroll: -15868
- return: -0.15868
- variance: 0.984727
- deviation: 0.992334
- error: 0.00313804
- result: "(-15.9 ± 0.6) %"
- ...
-
- ```
-
- > **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...
-
- -------
- :::{.text-center}
- [Previous](../00-internal) | [Index](../) | [Next](../05-no-bust)
- :::
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