Rebol3 Code Examplex
Get system command output
Run a system command and capture its output.
Rebol [
title: "Rosetta code: Get system command output"
file: %Get_system_command_output.r3
url: https://rosettacode.org/wiki/Bitmap/Get_system_command_output
]
system-command: function[
"Execute a system command and get its output"
command [string!] "The shell command string to execute"
][
out: copy "" ;; Buffer to capture stdout
err: copy "" ;; Buffer to capture stderr
;; Run the command in a shell, routing stdout -> out, stderr -> err
;; Returns an integer exit code (0 = success)
res: call/shell/output/error :command :out :err
;; Return all three results as a block for multi-value destructuring
reduce [res out err]
]
;; Pick the correct directory-listing command for the current OS
command: either system/platform = 'Windows ["dir"]["ls -la"]
;; Execute the command and unpack the returned [exit-code stdout stderr] block
set [res out err] system-command :command
;; Print stdout on success (exit code 0), otherwise print stderr
print either res == 0 [out][err]
Output:
Volume in drive C is OS
Volume Serial Number is 16C0-E786
Directory of c:\Dev\Builder\tree\rebol\Rebol-RosettaCode\tasks
06/01/2026 01:05 PM <DIR> .
04/10/2026 11:06 PM <DIR> ..
04/10/2026 06:15 PM 9 .gitignore
06/01/2026 12:41 PM 1,350 100_doors.r3
04/09/2026 09:27 PM 3,769 100_prisoners.r3
04/16/2026 02:58 PM 3,349,503 135-0.txt
04/09/2026 09:27 PM 732 21_game.r3
04/09/2026 09:27 PM 1,315 24_game.r3
04/09/2026 09:27 PM 3,430 9_billion_names_of_God_the_integer.r3
10/14/2025 06:12 PM 6,640 abbrev.txt
04/09/2026 09:27 PM 1,523 Abbreviations,_automatic.r3
04/09/2026 09:27 PM 1,836 Abbreviations,_easy.r3
04/09/2026 09:27 PM 2,175 Abbreviations,_simple.r3
04/09/2026 09:27 PM 832 ABC_correlation.r3
04/09/2026 09:27 PM 1,602 ABC_problem.r3
04/09/2026 09:27 PM 706 ABC_words.r3
04/09/2026 09:27 PM 3,153 Abelian_sandpile_model-Identitys.r3
04/09/2026 09:27 PM 1,826 Abundant_odd_numbers.r3
04/09/2026 09:27 PM 1,508 Additive_primes.r3
04/09/2026 09:27 PM 1,306 Almost_prime.r3
04/09/2026 09:27 PM 2,882 Amb.r3
04/09/2026 09:27 PM 1,910 Anagrams-Deranged_anagrams.r3
04/09/2026 09:27 PM 1,350 Anagrams.r3
04/09/2026 09:27 PM 4,869 Anagram_generator.r3
05/01/2026 02:15 PM 1,196 Angles_(geometric),_normalization_and_conversion.r3
04/09/2026 09:27 PM 901 Anti-primes.r3
04/09/2026 09:27 PM 451 Append_numbers_at_same_position_in_strings.r3
06/01/2026 12:56 PM 580,477 Archimedean_spiral.png
04/09/2026 09:27 PM 1,748 Archimedean_spiral.r3
04/09/2026 09:27 PM 4,398 Arithmetic_evaluation.r3
04/09/2026 09:27 PM 829 Attractive_numbers.r3
05/22/2026 12:14 PM 981 Audio_alarm.r3
04/09/2026 09:27 PM 2,514 Audio_frequency_generator.r3
04/09/2026 09:27 PM 2,610 Audio_overlap_loop.r3
04/09/2026 09:27 PM 6,854 Autogram_checker.r3
04/09/2026 09:27 PM 2,949 Babylonian_spiral.r3
04/10/2026 11:06 PM 916 Balanced_brackets.r3
06/01/2026 12:59 PM 36,457 barnsley-fern.png
04/09/2026 09:27 PM 1,036 Barnsley_fern.r3
04/18/2026 11:05 PM 3,848 Bifid_cipher.r3
04/09/2026 09:27 PM 2,244 Bilinear_interpolation.r3
04/09/2026 09:27 PM 1,775 Biorhythms.r3
04/09/2026 09:27 PM 2,163 Bitcoin_address_validation.r3
04/09/2026 09:27 PM 2,657 Bitmap-Flood_fill.r3
04/09/2026 09:27 PM 928 Bitmap-Histogram.r3
04/09/2026 09:27 PM 2,139 Bitmap-Midpoint_circle_algorithm.r3
04/09/2026 09:27 PM 1,395 Bitmap-Read_a_PPM_file.r3
04/09/2026 09:27 PM 1,681 Bitmap-Write_a_PPM_file.r3
04/09/2026 09:27 PM 2,279 Bitwise_IO.r3
04/09/2026 09:27 PM 662 Bitwise_operations.r3
04/09/2026 09:27 PM 5,334 Boids.r3
04/09/2026 09:27 PM 3,817 Box_the_compass.r3
04/09/2026 09:27 PM 2,416 Bulls_and_cows-player.r3
04/09/2026 09:27 PM 1,854 Bulls_and_cows.r3
04/09/2026 09:27 PM 2,904 Burrows-Wheeler_transform.r3
05/14/2026 11:23 AM 834 Caesar_cipher.r3
04/09/2026 09:27 PM 2,013 Calendar_for_REAL_programmers.r3
05/14/2026 11:50 PM 1,571 Camel_case_and_snake_case.r3
04/15/2026 10:53 AM 2,715 Card_shuffles.r3
04/09/2026 09:27 PM 945 Catalan_numbers-Pascal's_triangle.r3
04/09/2026 09:27 PM 403 Catalan_numbers.r3
04/09/2026 09:27 PM 1,835 Chinese_zodiac.r3
04/09/2026 09:27 PM 2,856 Color_quantization-median_cut.r3
04/09/2026 09:27 PM 10,473 Color_quantization-octree.r3
04/09/2026 09:27 PM 3,061 Conway's_Game_of_Life.r3
04/09/2026 09:27 PM 2,728 Count_the_coins_0-1.r3
04/09/2026 09:27 PM 936 Create_an_HTML_table.r3
04/09/2026 09:27 PM 400 Create_a_two-dimensional_array_at_runtime.r3
04/09/2026 09:27 PM 1,457 CSV_data_manipulation.r3
04/09/2026 09:27 PM 1,540 CSV_to_HTML_translation.r3
04/09/2026 09:27 PM 602 Currency.r3
06/01/2026 01:05 PM 108 data.fasta
04/15/2026 06:24 PM 1,006 Deal_cards_for_FreeCell.r3
06/01/2026 01:05 PM 11,906 Death_Star.jpg
05/07/2026 07:00 PM 7,281 Death_Star.r3
05/07/2026 07:00 PM 1,722 Death_Star_ASCII.r3
04/09/2026 09:27 PM 1,121 Digital_root.r3
04/09/2026 09:27 PM 950 Display_a_linear_combination.r3
04/09/2026 09:27 PM 1,700 Dragon_curve.r3
06/01/2026 01:05 PM 4,039 draw-cuboid.png
06/01/2026 01:05 PM 10,854 draw-sphere.jpg
04/09/2026 09:27 PM 1,699 Draw_a_clock.r3
05/13/2026 02:34 PM 1,205 Draw_a_cuboid.r3
04/09/2026 09:27 PM 438 Draw_a_pixel.r3
05/13/2026 04:25 PM 2,832 Draw_a_sphere.r3
06/01/2026 12:59 PM 84,428 drumloop.wav
04/09/2026 09:27 PM 881 Ethiopian_multiplication.r3
04/09/2026 09:27 PM 497 Euler's_constant.r3
04/09/2026 09:27 PM 1,126 Euler_method.r3
04/09/2026 09:27 PM 2,488 Evolutionary_algorithm.r3
04/09/2026 09:27 PM 1,220 Exactly_three_adjacent_3_in_lists.r3
04/09/2026 09:27 PM 1,802 Execute_Brainfuck.r3
05/13/2026 03:20 PM 620 Extend_your_language.r3
04/09/2026 09:20 PM 2,489 FASTA_format.r3
04/19/2026 01:22 PM 716 Fibonacci_sequence.r3
06/01/2026 01:00 PM 7,140 Filledcirc.png
04/11/2026 12:25 PM 397 Find_prime_n_such_that_reversed_n_is_also_prime.r3
04/09/2026 09:27 PM 1,085 First-class_functions-Use_numbers_analogously.r3
06/01/2026 12:42 PM 2,362 Five_weekends.r3
06/01/2026 01:05 PM 95,164 fractal-tree.png
04/09/2026 09:27 PM 2,444 Fractal_tree.r3
04/10/2026 11:00 AM 3,596 Fraction_reduction.r3
04/19/2026 02:19 PM 1,437 Fractran.r3
04/09/2026 09:27 PM 1,281 Gapful_numbers.r3
04/09/2026 09:27 PM 1,070 Get_system_command_output.r3
04/11/2026 12:06 PM 761 Gosper's_hack.r3
04/16/2026 10:32 AM 6,953 Go_fish.r3
04/09/2026 09:27 PM 5,599 Greed.r3
04/09/2026 09:27 PM 2,127 GSTrans_string_conversion.r3
05/07/2026 12:23 PM 368,458 Harriss_Spiral.png
05/07/2026 03:51 PM 4,107 Harriss_Spiral.r3
04/09/2026 09:27 PM 657 Hash_join.r3
04/09/2026 09:27 PM 4,824 Huffman_coding.r3
06/01/2026 01:00 PM 65 image.ppm
04/09/2026 09:27 PM 1,753 Image_noise.r3
04/09/2026 09:27 PM 1,266 Increment_loop_index_within_loop_body.r3
04/10/2026 06:01 PM 1,338 Integer_overflow.r3
04/09/2026 09:27 PM 1,205 ISBN13_check_digit.r3
04/09/2026 09:27 PM 2,174 I_before_E_except_after_C.r3
04/09/2026 09:27 PM 1,651 Jacobsthal_numbers.r3
05/01/2026 05:02 PM 1,368 JSON_pointer.r3
04/18/2026 02:33 PM 2,666 Knapsack_problem-0-1.r3
04/18/2026 01:53 PM 3,872 Knapsack_problem-Bounded.r3
04/18/2026 09:44 PM 1,639 Knapsack_problem-Continuous.r3
04/18/2026 09:42 PM 2,160 Knapsack_problem-Unbounded.r3
04/09/2026 04:03 PM 2,376 Knight's_tour.r3
04/09/2026 09:27 PM 1,721 Knuth_shuffle.r3
04/09/2026 09:27 PM 3,614 Largest_number_divisible_by_its_digits.r3
04/09/2026 09:27 PM 1,132 Leap_year.r3
05/01/2026 01:32 AM 2,446 Legendre_prime_counting_function.r3
06/01/2026 01:00 PM 1,302,665 Lenna100-larger.png
02/24/2026 12:06 PM 43,485 Lenna100.jpg
06/01/2026 01:00 PM 18,083 Lenna50-bw.png
02/24/2026 12:06 PM 23,894 Lenna50.jpg
04/16/2026 03:25 PM 1,084 Letter_frequency.r3
04/16/2026 02:27 PM 1,941 Levenshtein_distance.r3
04/09/2026 09:27 PM 1,512 Longest_common_suffix.r3
04/10/2026 11:41 AM 1,434 Look-and-say_sequence.r3
04/09/2026 09:27 PM 2,017 Loop-With_multiple_ranges.r3
04/09/2026 09:27 PM 972 Loops-Wrong_ranges.r3
04/09/2026 09:27 PM 2,231 Ludic_numbers.r3
04/09/2026 09:27 PM 1,871 Luhn_test_of_credit_card_numbers.r3
04/09/2026 09:27 PM 3,431 Lychrel_numbers.r3
04/09/2026 09:27 PM 2,936 LZW_compression.r3
04/09/2026 09:27 PM 1,756 Mandelbrot_set.r3
04/10/2026 04:55 PM 3,187 Mayan_numerals.r3
04/19/2026 03:37 PM 2,022 Maze_generation.r3
06/01/2026 01:00 PM 1,430 midpoint-circles.png
04/10/2026 05:24 PM 744 Minimum_primes.r3
06/12/2019 10:27 PM 79,712 MnichRadovani.mp3
04/09/2026 09:27 PM 2,088 Morse_code.r3
04/09/2026 09:27 PM 1,073 Multiton.r3
06/01/2026 01:05 PM 94 new.csv
04/09/2026 09:27 PM 1,270 Nim_game.r3
04/09/2026 09:27 PM 1,313 Numbers_divisible_by_their_individual_digits,_but_not_by_the_product_of_their_digits.r3
02/24/2026 12:06 PM 179 objects.dat
04/09/2026 09:27 PM 3,078 Object_serialization.r3
04/09/2026 09:27 PM 1,227 Ordered_words.r3
04/09/2026 09:27 PM 1,815 Padovan_n-step_number_sequences.r3
04/09/2026 09:27 PM 1,538 Pairs_with_common_factors.r3
04/09/2026 09:27 PM 1,379 Palindrome_detection.r3
04/09/2026 09:27 PM 3,722 Palindromic_gapful_numbers.r3
04/09/2026 09:27 PM 6,081 Parsing-Shunting-yard_algorithm.r3
03/06/2026 07:03 PM 23,929 pentagram.png
04/09/2026 09:27 PM 913 Pentagram.r3
04/09/2026 09:27 PM 6,301 Permutation_test.r3
04/19/2026 02:19 PM 3,012 Pick_random_element.r3
04/29/2026 10:12 AM 1,057 Piprimes.r3
04/09/2026 09:27 PM 1,781 Playing_cards.r3
04/15/2026 04:50 PM 3,066 Poker_hand_analyser.r3
05/13/2026 11:09 AM 2,689 Polynomial_regression.r3
10/14/2025 06:12 PM 952,427 polyspiral.png
04/09/2026 09:27 PM 2,025 Polyspiral.r3
10/14/2025 06:12 PM 287,376 pythagoras-tree.jpg
04/09/2026 09:27 PM 1,605 Pythagoras_tree.r3
06/01/2026 01:01 PM 159,918 Quantum_frog-16-colors.png
06/01/2026 01:01 PM 32,557 Quantum_frog-3-colors.png
06/01/2026 01:01 PM 89,489 Quantum_frog-octree-16-colors.png
06/01/2026 01:01 PM 138,010 Quantum_frog-octree-32-colors.png
03/11/2026 08:54 PM 389,441 quantum_frog.png
04/09/2026 09:27 PM 815 Quine.r3
05/13/2026 11:04 PM 2,088 Read_a_configuration_file.r3
04/09/2026 09:27 PM 972 Recaman's_sequence.r3
04/09/2026 09:27 PM 2,398 Reduced_row_echelon_form.r3
04/09/2026 09:27 PM 1,290 Rock-paper-scissors.r3
04/09/2026 09:27 PM 3,583 Rosetta_Code-Count_examples.r3
04/09/2026 09:27 PM 2,227 Rosetta_Code-Find_unimplemented_tasks.r3
04/09/2026 09:27 PM 2,993 Rosetta_Code-Rank_languages_by_popularity.r3
04/09/2026 09:27 PM 1,348 RPG_attributes_generatot.r3
04/09/2026 09:27 PM 1,931 Sattolo_cycle.r3
04/18/2026 11:28 PM 845 Self-describing_numbers.r3
04/09/2026 09:27 PM 693 Semordnilap.r3
04/09/2026 09:27 PM 2,432 SHA-256_Merkle_tree.r3
04/09/2026 09:27 PM 416 Show_ASCII_table.r3
05/14/2026 09:22 AM 378 Show_the_epoch.r3
05/15/2026 11:36 AM 1,022 Sierpinski_carpet.r3
05/15/2026 11:02 AM 701 Sierpinski_triangle.r3
04/09/2026 09:27 PM 1,413 Sieve_of_Eratosthenes.r3
04/09/2026 09:27 PM 3,386 Sieve_of_Pritchard.r3
05/07/2026 10:44 AM 621 Sleeping_Beauty_problem.r3
05/29/2026 10:11 AM 800 Soloway's_recurring_rainfall.r3
05/13/2026 11:26 AM 802 Sorting_algorithms-Bubble_sort.r3
05/12/2026 11:27 PM 829 Sorting_algorithms-Comb_sort.r3
05/12/2026 01:59 PM 1,016 Sorting_algorithms-Counting_sort.r3
04/10/2026 11:06 PM 912 Sorting_algorithms-Gnome_sort.r3
05/12/2026 01:23 PM 1,393 Sorting_algorithms-Insertion_sort.r3
05/13/2026 12:15 PM 1,618 Sorting_algorithms-Quicksort.r3
05/13/2026 01:07 PM 1,659 Sorting_algorithms-Radix_sort.r3
05/13/2026 12:08 PM 1,446 Sorting_algorithms-Stooge_sort.r3
05/29/2026 10:55 AM 934 Sort_a_list_of_object_identifiers.r3
05/12/2026 01:42 PM 728 Sort_stability.r3
05/15/2026 10:16 AM 1,568 Soundex.r3
05/15/2026 11:10 AM 1,119 Sparkline_in_unicode.r3
04/09/2026 09:27 PM 1,292 Spiral_matrix.r3
06/01/2026 12:42 PM 2,921 Statistics-Normal_distribution.r3
05/29/2026 03:25 PM 1,335 Stem-and-leaf_plot.r3
04/18/2026 10:27 PM 2,832 Straddling_checkerboard.r3
05/29/2026 02:47 PM 1,000 String_comparison.r3
05/14/2026 12:00 AM 532 Strip_a_set_of_characters_from_a_string.r3
04/09/2026 09:27 PM 1,825 Sub-unit_squares.r3
05/15/2026 09:49 AM 729 Sudan_function.r3
05/14/2026 11:20 AM 414 Temperature_conversion.r3
04/09/2026 09:27 PM 2,284 Terminal_control-Restricted_width_positional_input-No_wrapping.r3
05/14/2026 09:07 AM 1,992 Ternary_logic.r3
06/01/2026 01:05 PM 65 test.csv
06/01/2026 01:05 PM 905 test.png
04/09/2026 09:27 PM 832 The_Twelve_Days_of_Christmas.r3
05/13/2026 10:01 AM 927 Time_a_function.r3
04/09/2026 09:27 PM 2,482 Transliterate_English_text_using_the_Greek_alphabet.r3
04/30/2026 05:26 PM 909 Truncate_a_file.r3
06/01/2026 01:00 PM 13,704 Unfilledcirc.png
03/04/2026 02:28 PM 206,403 unixdict.txt
04/11/2026 02:36 PM 459 URL_decoding.r3
04/11/2026 03:13 PM 752 URL_encoding.r3
04/09/2026 09:27 PM 1,639 Validate_International_Securities_Identification_Number.r3
05/07/2026 09:20 AM 1,969 Vector.r3
05/07/2026 10:23 AM 921 Vector_products.r3
04/09/2026 09:27 PM 1,909 Vigenere_cipher.r3
04/19/2026 12:44 AM 713 Walk_a_directory-Non-recursively.r3
04/19/2026 12:22 AM 1,216 Walk_a_directory-Recursively.r3
04/15/2026 04:47 PM 2,725 War_card_game.r3
05/01/2026 02:19 PM 8,010 Wave_function_collapse.r3
05/14/2026 11:03 AM 2,563 Wordiff.r3
04/09/2026 09:27 PM 1,822 Wordle_comparison.r3
04/16/2026 03:12 PM 1,020 Word_frequency.r3
05/14/2026 09:43 AM 1,870 Word_wheel.r3
05/13/2026 07:40 PM 870 Write_language_name_in_3D_ASCII-v2.r3
05/13/2026 05:28 PM 1,762 Write_language_name_in_3D_ASCII.r3
04/16/2026 07:06 PM 2,231 XXXX_redacted.r3
04/09/2026 09:27 PM 792 Zig-zag_matrix.r3
05/22/2026 03:10 PM 2,318 _unimplemented_tasks.r3
249 File(s) 8,738,224 bytes
2 Dir(s) 834,285,867,008 bytes free