guide.md

Quick Guide

Command mode uses simple shell-like syntax

git commit -a

Forms starting with parenthesis are considered as Clojure code

(+ 1 2)

Glob patterns and environment variables are expanded

ls *.txt

ls $HOME

cd ~/Downloads

Use output from a command or function as arguments to other command

echo (+ 1 2)
echo (sh-str date)

Piping output between commands

ls | head

Piping with functions works similarly to ->> threading macro

ls | (clojure.string/upper-case)

ls | #(clojure.string/replace % #"\.txt" ".md")

Use special |> pipe operator to split input into sequence of lines

ls |> (reverse) | (take 5)

Redirects - note that there must be spaces around redirection operators > and >>

ls > files.txt

echo hi >> file.txt

ls 2 > files.txt

Command status

echo hi && echo OK

! echo hi || echo FAILED

Examples

Most of helper utilities can be replaced with functions on sequences.

bash:  ls | head -n 5
closh: ls |> (take 5)

bash:  ls | tail -n 5
closh: ls |> (take-last 5)

bash:  ls | tail -n +5
closh: ls |> (drop 4)

; Print filenames starting with "."
bash:  ls -a | grep "^\\."
closh: ls -a |> (filter #(re-find #"^\." %))

; Print only odd numbered lines counting from 1
bash:  ls | sed -n 1~2p
closh: ls |> (keep-indexed #(when (odd? (inc %1)) %2))

; Math
bash:  echo '(1 + sqrt(5))/2' | bc -l
closh: (/ (+ 1 (Math.sqrt 5)) 2)

Control flow

For loops:

for f in /sys/bus/usb/devices/*/power/wakeup; do echo $f; cat $f; done

ls /sys/bus/usb/devices/*/power/wakeup |> (map #(str % "\n" (sh-str cat (str %)))) | cat

If conditionals:

if test -f package.json; then echo file exists; else echo no file; fi

echo (if (sh-ok test -f package.json) "file exists" "no file")

Sequence of commands

bash:  ls; echo hi
closh: (sh ls) (sh echo hi)

Reference

Environment variables

There are some helper functions for doing common things with environment variables

setenv: set environment variable

setenv "ONE" "1"
=> ("1")
(setenv "ONE" "1")
=> ("1")
(setenv "ONE" "1" "TWO" "2")
=> ("1" "2")

getenv: get environment variable

getenv "ONE"
=> "1"
(getenv "ONE")
=> "1"
(getenv "ONE" "TWO")
=> {"ONE" "1", "TWO" "2"}
getenv
=> ;; returns a map of all environment variables

source-shell: run bash scripts and import the resulting environment variables into the closh environment

(source-shell "export ONE=42")
=> nil
getenv "ONE"
=> "42"

source-shell defaults to bash but you can use other shells:

(source-shell "zsh" "source complicated_script.zsh")
=> nil
getenv "SET_BY_COMPLICATED_SCRIPT"
=> "..."

To set a temporary variable while running a command, do this:

env VAR=1 command

Which is equivalent to bash:

VAR=1 command

Custom prompt

The prompt can be customized by defining closh-prompt function in ~/.closhrc file.

For example you can use powerline prompt like this:

(require-macros '[closh.core :refer [sh-str]])

(defn closh-prompt []
  (sh-str powerline-shell --shell bare))

Or you can reuse existing prompt from fish shell:

(require-macros '[closh.core :refer [sh-str]])

(defn closh-prompt []
  (sh-str fish -c fish_prompt)

Bash prompt format can be used via decode-prompt module. Install it with npm install -g decode-prompt. Then use it like:

(require '[cljs.nodejs])

(def decode-prompt (js/require "decode-prompt"))

(def PS1 "\\[\\033[01;32m\\]\\u@\\h\\[\\033[00m\\]:\\[\\033[01;34m\\]\\w\\[\\033[00m\\]\\$ ")

(defn closh-prompt []
  (decode-prompt PS1 #js{:env js/process.env}))

Quoting

Prevent some expansion is same like bash with double-quoted string:

echo "*"

Disable expansion completely with a single quote:

bash:  echo '$HOME'
closh: echo '$HOME ; notice there is only one quote

; if the quoted string has spaces wrap in double quotes and then prepend single quote
bash:  echo '$HOME $PWD'
closh: echo '"$HOME $PWD"