Table of Contents

• Child Process
  • childprocess.spawn(command, args, options)
  • childprocess.exec(command[, options], callback)
  • childprocess.execFile(file[, args, options, callback])

Child Process#

It is possible to stream data through a child's stdin, stdout, and stderr in a fully non-blocking way.

childprocess.spawn(command, args, options)#

Spawns a command line process.

Since the data coming in is a stream, you may want to pass it through a filter like the luvit line emitter package to get lines instead.

function example()
  local LineEmitter = require('line-emitter').LineEmitter
  local childProcess = require('childprocess')
  local function run(command, args, options)
    local stdout, stderr = LineEmitter:new(), LineEmitter:new()
    local child = childProcess.spawn(command, args, options)
    child.stdout:pipe(stdout)
    child.stderr:pipe(stderr)
    return child, stdout, stderr
  end

  local child = run('ls', {'-hal'}, {})
  child:on('data', print)
end

example()

total 2
drwxr-xr-x   31 root  wheel   1.1K Aug 21 16:39 .
drwxr-xr-x   31 root  wheel   1.1K Aug 21 16:39 ..

Options can have the following k-v pairs:

detached = [Boolean]
stdio = [Array]
cwd = [String]
uid = [Number]
gid = [Number]

childprocess.exec(command[, options], callback)#

Executes the supplied command and returns data returned in the callback.
The callback can be either a function or a thread for coroutine style code.
The command can have arguments e.g. childprocess.exec('ls -a', print).

Options can have the following k-v pairs:

timeout = [Number]  
maxBuffer = [Integer, default: 4 * 1024]
signal = [String, default: 'SIGTERM'] 
shell = [String, default: 'cmd.exe' or '/bin/sh']

Additionally since this function delegates to Spawn, all spawn option k-vs are also valid.

childprocess.execFile(file[, args, options, callback])#

Similiar to exec but the arguments for the command/file must be supplied as a string to the second parameter. Also, callback is optional as well here.