README.md
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Michiel Borkent
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README.md
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README.md
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@ -21,45 +21,58 @@ If you're a bash expert, you probably don't need this. But for those of us who
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can use a bit of Clojure in their shell scripts, it may be useful.
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Babashka runs as a [GraalVM](https://github.com/oracle/graal) binary which
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results in fast startup times:
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results in faster startup time than Clojure on the JVM.
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``` shellsession
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$ time clojure -e "(+ 1 2 3)"
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6
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clojure -e "(+ 1 2 3)" 3.29s user 0.32s system 99% cpu 3.638 total
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$ time planck -e '(+ 1 2 3)'
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6
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plk -e '(+ 1 2 3)' 1.34s user 0.16s system 127% cpu 1.172 total
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$ time bb '(+ 1 2 3)'
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6
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bb '(+ 1 2 3)' 0.01s user 0.01s system 37% cpu 0.046 total
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```
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It uses [sci](https://github.com/borkdude/sci) for interpreting Clojure. A
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trade-off is that [sci](https://github.com/borkdude/sci) implements only a
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subset of Clojure. Also, execution time may be slower than Clojure on the JVM or
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(self-hosted) ClojureScript for more CPU-intensive calculations like:
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``` shellsession
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(last (take 1000000 (repeatedly #(+ 1 2 3))))
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```
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This would take 5 seconds using babashka, around half a second using self-hosted
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ClojureScript and around 200ms in Clojure on the JVM.
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So the sweet spot for babashka is executing tasks from the command line where
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fast startup time is preferred, in the same space where you would use bash.
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The sweet spot for babashka is executing short Clojure snippets in the same
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space where you would use bash.
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Where it can, babashka calls the regular implementation of Clojure on the JVM
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and proxies common Java packages like `System` and `File`, so writing code in it
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should be familiar if you're already using Clojure on the JVM.
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Reasons why babashka may not be the right fit for your use case:
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- It uses [sci](https://github.com/borkdude/sci) for interpreting Clojure. Sci
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implements only a subset of Clojure.
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- Execution time of longer running programs may be slower.
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- External libraries are not available (although you may use `load-file` for
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loading external scripts).
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## Status
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Experimental. Breaking changes are expected to happen at this phase.
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## Examples
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``` shellsession
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$ ls | bb -i '*in*'
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["LICENSE" "README.md" "bb" "doc" "pom.xml" "project.clj" "reflection.json" "resources" "script" "src" "target" "test"]
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$ ls | bb -i '(count *in*)'
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12
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$ bb '(vec (dedupe *in*))' <<< '[1 1 1 1 2]'
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[1 2]
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$ bb '(filterv :foo *in*)' <<< '[{:foo 1} {:bar 2}]'
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[{:foo 1}]
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$ bb '(#(+ %1 %2 %3) 1 2 *in*)' <<< 3
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6
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$ ls | bb -i '(filterv #(re-find #"reflection" %) *in*)'
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["reflection.json"]
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$ bb '(run! #(shell/sh "touch" (str "/tmp/test/" %)) (range 100))'
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$ ls /tmp/test | bb -i '*in*'
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["0" "1" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "2" "20" "21" ...]
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$ bb -O '(repeat "dude")' | bb --stream '(str *in* "rino")' | bb -I '(take 3 *in*)'
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("duderino" "duderino" "duderino")
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```
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More examples can be found in the [gallery](#gallery).
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## Installation
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### Brew
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@ -119,9 +132,9 @@ Everything after that is bound to *command-line-args*.
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The `clojure.core` functions are accessible without a namespace alias.
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The following namespaces are required by default and only available
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through the aliases. If not all vars are available, they are enumerated
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explicitly.
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The following namespaces are required by default and available through the
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pre-defined aliases. You may use `require` + `:as` and/or `:refer` on these
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namespaces. If not all vars are available, they are enumerated explicitly.
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- `clojure.string` aliased as `str`
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- `clojure.set` aliased as `set`
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@ -182,37 +195,6 @@ $ bb '((fn [x] (println x) (when (not (sig/pipe-signal-received?)) (recur (inc x
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2
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```
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## Examples
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``` shellsession
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$ ls | bb -i '*in*'
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["LICENSE" "README.md" "bb" "doc" "pom.xml" "project.clj" "reflection.json" "resources" "script" "src" "target" "test"]
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$ ls | bb -i '(count *in*)'
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12
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$ bb '(vec (dedupe *in*))' <<< '[1 1 1 1 2]'
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[1 2]
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$ bb '(filterv :foo *in*)' <<< '[{:foo 1} {:bar 2}]'
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[{:foo 1}]
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$ bb '(#(+ %1 %2 %3) 1 2 *in*)' <<< 3
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6
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$ ls | bb -i '(filterv #(re-find #"reflection" %) *in*)'
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["reflection.json"]
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$ bb '(run! #(shell/sh "touch" (str "/tmp/test/" %)) (range 100))'
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$ ls /tmp/test | bb -i '*in*'
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["0" "1" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "2" "20" "21" ...]
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$ bb -O '(repeat "dude")' | bb --stream '(str *in* "rino")' | bb -I '(take 3 *in*)'
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("duderino" "duderino" "duderino")
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```
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More examples can be found in the [gallery](#gallery).
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## Running a file
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Scripts may be executed from a file using `-f` or `--file`:
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