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Perl で作る tiny shell

Perl で作る tiny shell

Perl で極限に機能を削った shell の作り方を紹介します

Kei Kamikawa

June 23, 2018
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  1. 1FSMͰ࡞Δ

    UJOZTIFMM
    )PLLBJEPQN

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  2. !DPEFIFY !$PEF)FY
    w .FSDBSJ *OD
    w %FWFMPQJOHNJDSPTFSWJDFT
    w 0LJOBXBQN
    w *MJLF1FSM94(P
    w IUUQTDPEFIFYIBUFCMPKQ

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  3. γΣϧͬͯ஌ͬͯ·͔͢

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  5. /P

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  6. $ pwd


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  7. $ pwd

    /Users/codehex

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  8. #BTI ;TI pTI

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  9. γΣϧʹ͸

    ༷ʑͳػೳ͕͋Γ·͢

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  10. ྫ͑͹

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  11. ύΠϓ

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  12. $ pwd | cat -n


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  13. $ pwd | cat -n

    1 /Users/codehex

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  14. Ξϯυ

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  15. $ pwd && echo hello


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  16. $ pwd && echo hello

    /Users/codehex

    hello

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  17. ͜ΕΒͷ

    ࣮૷Λ஌͍ͬͯ·͔͢ʁ

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  18. ࠓ೔࿩͢಺༰

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  19. ࠓ೔࿩͢಺༰
    w ࠷௿ݶͷγΣϧͷఆٛ
    w ߏจղੳ
    w ίϚϯυͷ࣮ߦ

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  20. ࠓ೔࿩͢಺༰
    w ࠷௿ݶͷγΣϧͷఆٛ
    w ߏจղੳ
    w ίϚϯυͷ࣮ߦ

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  21. ࠷௿ݶͷγΣϧͷఆٛ
    UJOZTIFMMͷಈ࡞Λఆٛ͢Δ

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  22. lUJOZTIFMMzNFBOT

    ΊͬͪΌখ͍͞γΣϧ

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  23. Ͳ͏͍͏ಈ࡞Λ͢Δ͔

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  24. Ͳ͏͍͏ಈ࡞Λ͢Δ͔
    w ୯ҰίϚϯυͷ࣮ߦ $ ls

    w ύΠϓͷ࣮ߦ $ ls | cat

    w ΞϯυʹΑΔෳ਺࣮ߦ $ ls && cat

    w αϒγΣϧ΍όοΫάϥϯυ࣮ߦ͸ࠓճؚΊ·ͤΜ

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  25. ࠓ೔࿩͢಺༰
    w ࠷௿ݶͷγΣϧͷఆٛ
    w ߏจղੳ
    w ίϚϯυͷ࣮ߦ

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  26. ߏจղੳ
    ެจఆٛͱߏจղੳثͷ࡞੒

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  27. $ cat | cat -n && ls

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  28. $ cat | cat -n && ls

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  29. $ cat | cat -n && ls

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  30. $ cat | cat -n && ls

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  31. $ cat | cat -n && ls

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  32. $ cat | cat -n && ls
    ࠨ͔Βӈʹղऍ͠·͢

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  33. ߏจͷఆٛ

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  34. ӈʹ࿈͍݁ͯ͘͠Α͏ʹ

    ఆٛ෇͚Λߦ͏

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  35. ߏจఆٛ
    • CMD: [a-zA-Z_-][0-9a-zA-Z_-]*
    • ARG: [0-9a-zA-Z_-]* | [0-9a-zA-Z_-]*
    • SHLL: '&&' |
    • PIPE: '|' |
    • AND: '&&' |

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  36. ߏจղੳثͷ࡞੒

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  37. ߏจղੳثʹඞཁͳཁૉ

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  38. ߏจղੳثʹඞཁͳཁૉ
    w จࣈྻͷεΩϟφʔ
    w ಡΈࠐΈҐஔ΍ಡΈऔͬͨจࣈྻΛอ࣋͢Δ
    w จࣈྻͷϚονϯά
    w εΩϟφʔͰಘͨจࣈྻ͕ߏจఆٛʹϚονͨ͠
    ͔Ͳ͏͔൑ผ͢Δ
    w Ϛονͨ͠จࣈྻʹҙຯΛ΋ͨͤΔ τʔΫϯԽ

    w ߏจ໦ͷੜ੒

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  39. 1FSMͰ͸ʁ

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  40. ਖ਼نදݱ

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  41. IUUQTQFSMEPDQFSMPSHQFSMPQIUNMD(@BTTFSUJPO@
    l"VTFGVMJEJPNGPSAlexAMJLF

    TDBOOFSTJTA/\G…/gcAʜz

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  42. /\G…/gc

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  43. /\G…/gc
    w A/cANPEJpFSͰ͸ݱࡏϚον͍ͯ͠ΔҐஔΛ

    อ࣋͢Δ͜ͱ͕Ͱ͖Δɻ
    • pos()ͰҐஔΛऔΓग़͢͜ͱ͕Մೳ
    • \GͰલճAm//gAͰϚονͨ͠ҐஔΛอ࣋͢Δ͜ͱ
    ͕Մೳ

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  44. εΩϟφʔͱϚονϯάͷ

    ໾ׂΛ΋ͭ͜ͱ͕Ͱ͖Δ ?P?
    W

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  45. ͜͜Ͱྑ͍৘ใ

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  46. ΊͬͪΌࢀߟʹͳΔϖʔδ
    w IUUQTHJUIVCDPNLBSVQBOFSVSBQ
    +40/CMPCNBTUFSMJC+40/1BSTFSQN
    w IUUQTHJUIVCDPNLBSVQBOFSVSB50.-
    1BSTFSCMPCNBTUFSMJC50.-1BSTFSQN

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  47. ࣮૷༷ࢠ

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  48. ߏจఆٛ
    • CMD: [a-zA-Z_-][0-9a-zA-Z_-]*
    • ARG: [0-9a-zA-Z_-]* | [0-9a-zA-Z_-]*
    • SHLL: '&&' |
    • PIPE: '|' |
    • AND: '&&' |

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  49. $.%

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  50. ߏจఆٛ
    • CMD: [a-zA-Z_-][0-9a-zA-Z_-]*
    • ARG: [0-9a-zA-Z_-]* | [0-9a-zA-Z_-]*
    • SHLL: '&&' |
    • PIPE: '|' |
    • AND: '&&' |

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  51. 4)--

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  52. ߏจఆٛ
    • CMD: [a-zA-Z_-][0-9a-zA-Z_-]*
    • ARG: [0-9a-zA-Z_-]* | [0-9a-zA-Z_-]*
    • SHLL: '&&' |
    • PIPE: '|' |
    • AND: '&&' |

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  53. 1*1&

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  54. ߏจఆٛ
    • CMD: [a-zA-Z_-][0-9a-zA-Z_-]*
    • ARG: [0-9a-zA-Z_-]* | [0-9a-zA-Z_-]*
    • SHLL: '&&' |
    • PIPE: '|' |
    • AND: '&&' |

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  55. "/%

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  56. ໦ΛQSJOU༷ͨ͠ࢠ
    $ cat | cat -n && ls

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  57. "/%
    1*1&
    DBU
    DBU
    MT
    $ cat | cat -n && ls

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  58. ͪͳΈʹ

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  59. $ cat | cat -n && ls

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  60. $ cat | cat -n && ls
    ࠨ͔Βӈʹղऍ͠·͢

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  61. ͳͷͰ

    ໦ΛḷΔͱ͖͸

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  62. "/%
    1*1&
    DBU
    DBU
    MT
    $ cat | cat -n && ls

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  63. "/%
    1*1&
    DBU
    DBU
    MT
    $ cat | cat -n && ls
    ᶃ ᶄ

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  64. "/%
    1*1&
    DBU
    DBU
    MT
    $ cat | cat -n && ls
    ᶃ ᶄ

    ᶆ ᶇ

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  65. ͜ΕΛجʹ

    ࣮ߦ͢ΔػೳΛ࡞੒͠·͢

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  66. ࠓ೔࿩͢಺༰
    w ࠷௿ݶͷγΣϧͷఆٛ
    w ߏจղੳ
    w ίϚϯυͷ࣮ߦ

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  67. ίϚϯυͷ࣮ߦ
    ߏจ໦Λجʹ࣮ߦ͢Δ

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  68. ࣮૷ͷલʹ

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  69. ඪ४ετϦʔϜʹ͍ͭͯ

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  70. w 45%*/ 4UBOEBSE*OQVU
    ඪ४ೖྗ
    w 45%065 4UBOEBSE0VUQVU
    ඪ४ग़ྗ
    w 45%&33 4UBOEBSE&SSPS
    ඪ४Τϥʔग़ྗ
    ඪ४ετϦʔϜ

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  71. ͜ΕΒ͸࣮࣭

    ϑΝΠϧͱͯ͠ѻΘΕ·͢

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  72. ୯ҰίϚϯυͷ

    ετϦʔϜͷϑϩʔ

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  73. $ cat

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  74. $ cat
    cat
    45%*/

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  75. $ cat
    cat
    45%*/
    45%065
    45%&33

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  76. $ cat
    GPSLΛ࢖͏ͱTIΛհ͞ͳ͍Ͱ࣮ߦՄೳ

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  77. ύΠϓͷϑϩʔ

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  78. $ fortune | cowsay

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  79. $ fortune | cowsay
    45%*/
    PS/PU

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  80. $ fortune | cowsay
    45%*/
    PS/PU
    45%065
    ᶃ ᶄ

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  81. $ fortune | cowsay
    45%*/
    PS/PU
    45%065 45%*/
    ᶃ ᶄ ᶅ

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  82. $ fortune | cowsay
    45%*/
    PS/PU
    45%065 45%*/ 45%065
    ᶃ ᶄ ᶅ ᶆ

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  83. ͜ΕΒͷίϚϯυ͸

    ผϓϩηεͰಈ͍͍ͯ·͢

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  84. $ ps a | cat
    1*%

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  85. ύΠϓͷ࣮૷

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  86. pipe my ($r, $w);

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  87. w $r͕3FBEFS $w͕8SJUFS
    w 8SJUFSʹσʔλ͕ॻ͖ࠐ·Εͨͱ͖

    3FBEFSͰͦͷσʔλΛಡΈऔΔ͜ͱ͕Մೳ
    pipe my ($r, $w);

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  88. ֤ϓϩηεؒͷετϦʔϜΛ

    pipe()Ͱܨ͛Δ͜ͱͰ࣮૷Մೳ

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  89. ͦͷ࣌ͷϑϩʔ

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  90. $ fortune | cowsay
    45%*/
    PS/PU
    45%065
    ᶃ ᶄ

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  91. $ fortune | cowsay
    45%*/
    PS/PU
    45%065
    ᶃ ᶄ ᶅ ᶆ
    8SJUFS
    3FBEFS

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  92. $ fortune | cowsay
    45%*/
    PS/PU
    45%065 45%*/ 45%065
    ᶃ ᶄ ᶅ ᶆ
    8SJUFS
    3FBEFS

    ᶈ ᶉ

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  93. ͳͷͰ࣮࣭

    ͜ͷΑ͏ʹߟ͑ΒΕΔ

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  94. $ fortune | cowsay
    45%*/
    PS/PU
    8SJUFS 3FBEFS 45%065
    ᶃ ᶄ ᶅ ᶆ

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  96. w ίϚϯυOPEFͰ͔ͭ਌OPEF͕ύΠϓͰ͸ͳ͍

    ৔߹͸ଈίϚϯυΛ࣮ߦ
    w ͦΕҎ֎͸ίϚϯυΛอ࣋͢Δ
    w ύΠϓOPEF͔ͭ਌͕ύΠϓOPEFͰ͸ͳ͍৔߹

    อ࣋͠ଓ͚ͨίϚϯυΛ࣮ߦ

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  97. Ξϯυͷϑϩʔ

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  98. $ echo hello && echo world

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  99. $ echo hello && echo world

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  100. $ echo hello && echo world
    ᶃ ᶄ

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  101. w ΞϯυOPEFʹདྷΔ·ͰʹࠨͷOPEFΛ

    શ࣮ͯߦ͢Δ
    w ੒ޭͨ͠৔߹ӈͷOPEFΛࠨͷOPEFͱಉ͡Α͏
    ʹ࣮ߦ͢Δ

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  102. ͜Ε͚ͩͰ

    UJOZTIFMM͕׬੒͠·͢ʂ

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  103. ·ͱΊ

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  104. ·ͱΊ
    w ӈʹ࿈͍݁ͯ͘͠Α͏ʹߏจఆٛͨ͠
    w γΣϧͷύΠϓɺΞϯυػೳΛཧղͯ͠ɺղੳ࣌ʹ
    ࣮ߦ͢ΔػೳΛ࡞੒ͨ͠

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  105. ࣭໰Ͳ͏ͧ
    https://github.com/Code-Hex/p5-Shell-Tiny

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