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56 lines
2.1 KiB
Org Mode
56 lines
2.1 KiB
Org Mode
#+title: Oil shell
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#+date: "2021-05-09 16:40:50 +08:00"
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#+date_modified: "2021-05-10 11:25:10 +08:00"
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#+language: en
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For future references, this note mainly notes Oil v0.8.7 and later versions.
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* What is Oil shell?
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A modern shell attempting the replace Bash slowly.
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The project has an ambitious goal with a wide scope.
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It is known for its shell-oriented blog and the developer is very responsive and active with shell-related posts.
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While there are multiple components in this project, we're focusing on two: *OSH and Oil shell*.
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- *OSH is the bridge between Bash and Oil.*
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It aims to be the most Bash-compatible shell that you can run most Bash scripts just fine.
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The point of this component is improving what's under the hood, imposing sensible defaults on them, and getting a wide reach since Bash is the most popular shell.
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While it may not run every Bash script in existence, the other point is to require minimal rewrites to run it with OSH.
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- *Oil shell is the modern replacement of Bash* from its syntax and behavior.
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It aims to be the shell for people familiar to Python, Ruby, JavaScript, and the like.
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This is the other side of the bridge that OSH aims to reach.
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* Tips and tricks
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- You can make an array so far with ~var x = %()~.
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- To push for an array, use ~push :ARRAY_VAR $ITEMS...~.
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- Oil has two main syntactic modes: command and expression mode.
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Command mode is more like Bash while expression mode is more like Python.
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This is how Oil can make a rich and expressive scripting that is closer to the shell.
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- Oil will go into expression mode in few places: + In RHS of an assignment expression.
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+ In ~if~ statements (e.g., ~if ($EXPR) { echo "WHOA" }~).
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+ Interpolated Oil expressions with ~$[]~ (e.g., ~$[true]~, ~$[len(ARGV)~).
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- Oil can parse different modes, making it possible to create DSLs and to deal with the complex syntax of the shell.
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- You can also create an array with ~[]~.
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The ~%()~ is more like for an array of objects.
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- You can enter into expression mode with ~_~.
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Although, this simply ignores the expression and will not be printed.
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Still pretty useful.
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