shelljs.exec

shelljs.exec

Replacement for shelljs' slow exec method - benchmarked 20x faster

Introduction

shelljs is FAST but its exec method is SLOW

• Use this module instead of shelljs' exec method for speeds 20x faster

• Use shelljs' other methods as they are lightning fast (e.g. shelljs.echo shelljs.which shelljs.cat)

This is a zero-dependency module

Usage

This module takes 2 arguments, the command to execute and an options object

On success:

var exec = require('shelljs.exec')
var cmdObj = exec('echo hello', {silent: true})

expect(cmdObj).to.eql({
  error: null,
  stdout: 'hello\n',
  stderr: '',
  code: 0,
  ok: true
})

On failure:

var exec = require('shelljs.exec')
var cmdObj = exec('blip blop', {silent: true})

expect(cmdObj.error).to.be.an('error')
expect(cmdObj.error.message).to.match(/not found|not recognized/)

expect(cmdObj.stdout).to.equal('')
expect(cmdObj.stderr).to.match(/not found|not recognized/)
expect(cmdObj.code).to.be.above(0)
expect(cmdObj.ok).to.be.false

Options object

Available options:

• silent: Do not echo any output to console - Defaults to false

• and any option available to Node.js' child_process.execSync

When the stdio option of child_process.execSync is provided, it overrides silent

Benchmarks

Benchmark test result logs are HERE

Generally speaking, on Linux shelljs.exec (this module) is 20 times faster and on Windows 5 times faster than shelljs' exec method.

However, shelljs supported commands, where available, are much faster than both. Use this module where a shelljs supported command is unavailable.

These tables compare average execution times based on 1000 test runs:

Linux (Travis CI) Node v6

command	shelljs.exec (this module)	shelljs.exec (from shelljs)		shelljs supported command
echo hello	4.16ms	103.45ms	24.9x slower	0.17ms (shelljs.echo)	24.4x faster
which git	75.43ms	169.85ms	2.3x slower	0.90ms (shelljs.which)	83.5x faster
cat file1 file2	3.97ms	105.03ms	26.5x slower	0.59ms (shelljs.cat)	6.7x faster
printf hello	3.17ms	97.84ms	30.8x slower	N/A
whoami	4.42ms	110.14ms	24.9x slower	N/A
git rev-parse --is-inside-work-tree	4.88ms	100.61ms	20.6x slower	N/A

Windows (GIT bash) Node v6.10.0

command	shelljs.exec (this module)	shelljs.exec (from shelljs)		shelljs supported command
echo hello	15.56ms	188.52ms	12.1x slower	0.43ms (shelljs.echo)	35.9x faster
which git	164.37ms	332.20ms	2.0x slower	1.19ms (shelljs.which)	138.6x faster
cat file1 file2	40.97ms	217.73ms	5.3x slower	0.77ms (shelljs.cat)	53.3x faster
printf hello	43.55ms	235.87ms	5.4x slower	N/A
whoami	45.26ms	247.77ms	5.5x slower	N/A
git rev-parse --is-inside-work-tree	43.41ms	231.35ms	5.3x slower	N/A

Limitations

• Currently this module does not support chaining (shelljs does)

• Currently this module only supports synchronous execution, asynchronous callbacks are not available (shelljs claims full async support)

Author says

But as the days of Noah were, so also will the coming of the Son of Man be. 38 For as in the days before the flood, they were eating and drinking, marrying and giving in marriage, until the day that Noah entered the ark, 39 and did not know until the flood came and took them all away, so also will the coming of the Son of Man be.

Matthew 24:37-39