| 1 | ---
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| 2 | title: Oils Reference
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| 3 | all_docs_url: ..
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| 4 | css_files: ../../web/base.css ../../web/manual.css ../../web/ref-index.css
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| 5 | default_highlighter: oils-sh
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| 6 | preserve_anchor_case: yes
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| 7 | ---
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| 8 | 
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| 9 | <div class="doc-ref-header">
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| 10 | 
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| 11 | **Oils Reference** —
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| 12 | [OSH](toc-osh.html) | [YSH](toc-ysh.html) | [Data Notation](toc-data.html)
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| 13 | 
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| 14 | </div>
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| 15 | 
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| 16 | <style>
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| 17 |   .highlight {
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| 18 |       background-color: #eee;
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| 19 |       padding-top: 0.1em;
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| 20 |       padding-bottom: 0.1em;
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| 21 |       padding-left: 1em;
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| 22 |       padding-right: 1em;
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| 23 |       /*
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| 24 |       font-size: 1.2em;
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| 25 |       */
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| 26 |   }
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| 27 | </style>
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| 28 | 
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| 29 | This reference has **three** tables of contents.  They link to topics within 15
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| 30 | chapters.
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| 31 | 
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| 32 | <span class="in-progress">(in progress)</span>
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| 33 | 
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| 34 | <div class="highlight">
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| 35 | 
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| 36 | [**OSH Table of Contents**](toc-osh.html) - Compatible
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| 37 | 
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| 38 | [**YSH Table of Contents**](toc-ysh.html) - New and Powerful
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| 39 | 
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| 40 | </div>
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| 41 | 
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| 42 | 1. [Types and Methods](chap-type-method.html)
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| 43 | 1. [Builtin Functions](chap-builtin-func.html)
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| 44 | 1. [Builtin Commands](chap-builtin-cmd.html)
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| 45 | 1. [Front End](chap-front-end.html)
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| 46 | 1. [Command Language](chap-cmd-lang.html)
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| 47 | 1. [OSH Assignment](chap-osh-assign.html)
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| 48 | 1. [YSH Command Language Keywords](chap-ysh-cmd.html)
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| 49 | 1. [Word Language](chap-word-lang.html)
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| 50 | 1. [YSH Expression Language](chap-expr-lang.html)
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| 51 | 1. [Mini Languages](chap-mini-lang.html)
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| 52 | 1. [Global Shell Options](chap-option.html)
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| 53 | 1. [Special Variables](chap-special-var.html)
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| 54 | 1. [Plugins and Hooks](chap-plugin.html)
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| 55 | 
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| 56 | <div class="highlight">
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| 57 | 
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| 58 | [**Data Notation Table of Contents**](toc-data.html)
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| 59 | 
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| 60 | </div>
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| 61 | 
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| 62 | 14. [JSON / J8 Notation](chap-j8.html)
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| 63 | 1. [Errors](chap-errors.html)
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| 64 | 
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| 65 | <div class="highlight">
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| 66 | 
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| 67 | [**Index**](chap-index.html)
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| 68 | 
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| 69 | </div>
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| 70 | 
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| 71 | ## `help` command
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| 72 | 
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| 73 | When you type [`help`][help] in OSH or YSH, it shows a URL to this reference,
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| 74 | or text extracted from it.
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| 75 | 
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| 76 | [help]: chap-builtin-cmd.html#help
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| 77 | 
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| 78 | ## About
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| 79 | 
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| 80 | [The source files]($oils-src:doc/) for this reference are in Markdown:
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| 81 | 
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| 82 |     REPO/
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| 83 |       doc/
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| 84 |         release-index.md     # /release/$VERSION/
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| 85 | 
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| 86 |         index.md             # All Docs on Oils, /release/$VERSION/doc/
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| 87 |         getting-started.md
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| 88 |         ...
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| 89 | 
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| 90 |         ref/
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| 91 |           index.md           # this page, the Oils Reference
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| 92 |           toc-osh.md         # OSH topics
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| 93 |           toc-ysh.md         # YSH topics
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| 94 |           toc-data.md        # Data language topics
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| 95 | 
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| 96 |           chap-cmd-lang.md   # chapter on the command language
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| 97 |           chap-front-end.md
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| 98 |           ...
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| 99 | 
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| 100 | The URLs mirror the source, with minor differences:
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| 101 | 
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| 102 |     /release/$VERSION/
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| 103 |       index.html
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| 104 |       doc/
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| 105 |         index.html
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| 106 |         getting-started.html
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| 107 |         ...
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| 108 | 
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| 109 |         ref/
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| 110 |           index.html
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| 111 |           toc-osh.html
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| 112 |           toc-ysh.html
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| 113 |           toc-data.html
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| 114 | 
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| 115 |           chap-cmd-lang.html
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| 116 |           chap-front-end.html
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| 117 |           ...
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| 118 | 
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| 119 | You can link to topics with internal anchors:
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| 120 | 
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| 121 | - [chap-cmd-lang.html#simple-command](chap-cmd-lang.html#simple-command)
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| 122 | - [chap-builtin-cmd.html#compgen](chap-builtin-cmd.html#compgen)
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| 123 | 
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| 124 | ### Terminology
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| 125 | 
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| 126 | This reference has a 3-level structure:
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| 127 | 
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| 128 | 1. *Chapter* - A big HTML page.
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| 129 |    - A chapter may apply to OSH, YSH, or both.
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| 130 | 1. *Section* - An `<h2>` heading in a chapter
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| 131 | 1. *Topic* - An `<h3>` heading in a chapter.  
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| 132 |    - It has a **globally unique** name like `doc-comment`, which is used in the
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| 133 |      `help` builtin.
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| 134 |    - A topic may apply to OSH, YSH, or both.
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| 135 | 
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| 136 | More terminology:
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| 137 | 
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| 138 | - *Table of Contents* - a doc with a dense list of topic links.
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| 139 | - *Card* - Some topics are exported as `help` builtin "cards".  They can be
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| 140 |   inline text, or a URL pointer.  A card may also link to POSIX or bash docs.
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