sh

This module provides a template string handler for executing shell commands synchronously.

Installation

yarn add sh or npm install sh

Usage

• Running a shell script
• Interpolation
• Errors
• Debugging

Running a shell script

Import the helper and use it as a template tag.

const sh = require('@bockit/sh')

sh`echo hello world` // 'hello world'

It works with multiline too

const sh = require('@bockit/sh')

sh`
  place=world
  echo Hello, $place!
  echo Goodbye.
`

// Hello, world!
// Goodbye.

The return value in this case will be all the output of the entire script.

Interpolation

If you interpolate a value into your template tag it will be escaped by shell-escape before being inserted into the command.

const sh = require('@bockit/sh')
const person = '"world"'

sh`echo hello ${person}` // 'hello "world"'

If you want to prevent escaping, use the sh.unsafe template tag.

const sh = require('@bockit/sh')
const person = '"world"'

sh.unsafe`echo hello ${person}` // 'hello world'

Errors

If the command exists with a non-zero value it will log the command and the stderr output on stderr before re-throwing the error you would have received from child_process.execSync

const sh = require('@bockit/sh')
const person = '"world'

sh.unsafe`echo hello ${person}`

Output:

  echo "hello
  /bin/sh: -c: line 0: unexpected EOF while looking for matching `"'
  /bin/sh: -c: line 1: syntax error: unexpected end of file
  
/Users/james/Documents/oss/@bockit/sh/index.js:35
    throw error
    ^

Error: Command failed: echo "hello
/bin/sh: -c: line 0: unexpected EOF while looking for matching `"'
/bin/sh: -c: line 1: syntax error: unexpected end of file

    at checkExecSyncError (child_process.js:483:13)
    at execSync (child_process.js:523:13)
    at execute (/Users/james/Documents/oss/@bockit/sh/index.js:31:12)
    at Function.unsafe (/Users/james/Documents/oss/@bockit/sh/index.js:16:10)
    at Test.<anonymous> (/Users/james/Documents/oss/@bockit/sh/test.js:40:29)
    at Test.bound [as _cb] (/Users/james/Documents/oss/@bockit/sh/node_modules/tape/lib/test.js:66:32)
    at Test.run (/Users/james/Documents/oss/@bockit/sh/node_modules/tape/lib/test.js:85:10)
    at Test.bound [as run] (/Users/james/Documents/oss/@bockit/sh/node_modules/tape/lib/test.js:66:32)
    at Immediate.next (/Users/james/Documents/oss/@bockit/sh/node_modules/tape/lib/results.js:71:15)
    at runCallback (timers.js:637:20)
error Command failed with exit code 1.

If you catch the error it will still log the command and output on stderr.

Debugging

Run with DEBUG=sh:commands to see a log of all commands run and from which directory they are run. Example:

  sh:commands executing: echo "hello" +0ms
  sh:commands -> current directory: /Users/james/Documents/oss/@bockit/sh +0ms
  sh:commands -> output:
  sh:commands   hello
  sh:commands    +3ms

Running Tests

yarn test