Github GitHub - google/zx: A tool for writing better scripts
source link: https://github.com/google/zx
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zx
#!/usr/bin/env zx await $`cat package.json | grep name` let branch = await $`git branch --show-current` await $`dep deploy --branch=${branch}` await Promise.all([ $`sleep 1; echo 1`, $`sleep 2; echo 2`, $`sleep 3; echo 3`, ]) await $`ssh medv.io uptime`
Bash is great, but when it comes to writing scripts,
people usually choose a more convenient programming language.
JavaScript is a perfect choice, but standard Node.js library
requires additional hassle before using. zx
package provides
useful wrappers around child_process
and gives sensible defaults.
Install
npm i -g zx
Documentation
Write your scripts in a file with .mjs
extension in order to
be able to use await
on top level. If you prefer .js
extension,
wrap your script in something like void async function () {...}()
.
Add next shebang at the beginning of your script:
#!/usr/bin/env zx
Now you will be able to run your script as:
chmod +x ./script.mjs ./script.mjs
Or via zx
bin:
zx ./script.mjs
Then using zx
bin or via shebang, all $
, cd
, fetch
, etc
available without imports.
$`command`
Executes given string using exec
function
from child_process
package and returns Promise<ProcessOutput>
.
let count = parseInt(await $`ls -1 | wc -l`) console.log(`Files count: ${count}`)
Example. Upload files in parallel:
let hosts = [...] await Promise.all(hosts.map(host => $`rsync -azP ./src ${host}:/var/www` ))
If executed program returns non-zero exit code, ProcessOutput
will be thrown.
try { await $`exit 1` } catch (p) { console.log(`Exit code: ${p.exitCode}`) console.log(`Error: ${p.stderr}`) }
ProcessOutput
class ProcessOutput { readonly exitCode: number readonly stdout: string readonly stderr: string toString(): string }
cd()
Changes working directory.
cd('/tmp') await $`pwd` // outputs /tmp
test()
Executes test
command using execSync
and returns true
or false
.
if (test('-f package.json')) { console.log('Yes') }
This is equivalent of next bash code:
if test -f package.json; then echo Yes; fi
fetch()
This is a wrapper around node-fetch package.
let resp = await fetch('http://wttr.in') if (resp.ok) { console.log(await resp.text()) }
question()
This is a wrapper around readline package.
type QuestionOptions = { choices: string[] } function question(query: string, options?: QuestionOptions): Promise<string>
Usage:
let username = await question('What is your username? ') let token = await question('Choose env variable: ', { choices: Object.keys(process.env) })
chalk
package
The chalk package available without importing inside scripts.
console.log(chalk.blue('Hello world!'))
fs
package
The fs package available without importing inside scripts.
let content = await fs.readFile('./package.json')
Promisified version imported by default. Same as if you write:
import {promises as fs} from 'fs'
os
package
The os package available without importing inside scripts.
await $`cd ${os.homedir()} && mkdir example`
$.shell
Specifies what shell is used. Default is /bin/sh
.
$.shell = '/bin/bash'
$.verbose
Specifies verbosity. Default: true
.
In verbose mode prints executed commands with outputs of it. Same as
set -x
in bash.
Importing
It's possible to use $
and others with explicit import.
#!/usr/bin/env node import {$} from 'zx' await $`date`
Executing remote scripts
If arg to zx
bin starts with https://
, it will be downloaded and executed.
zx https://medv.io/example-script.mjs
License
Disclaimer: This is not an officially supported Google product.
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