API Reference - uv.process

August 30, 2014 ยท View on GitHub

The process module provides functions for managing processes.

process.spawn(args)

Spawn a child process. args should be a table containing the executable path at index 1, arguments at indexes 2+, and any of the following options:

  • env: A table of environment variables as key/value pairs. If env is omitted, the child process will inherit the parent's environment.

  • cwd: Current working directory of the child process.

  • stdin: File descriptor to inherit as stdin. 0 causes it to inherit the parent's stdin.

  • stdout: File descriptor to inherit as stdout. 1 causes it to inherit the parent's stdout.

  • stderr: File descriptor to inherit as stderr. 2 causes it to inherit the parent's stderr.

  • uid: User ID under which to run.

  • gid: Group ID under which to run.

Returns the signal that terminated the child process, or 0 on successful exit.

local signal = process.spawn { '/bin/echo', 'Hello', 'world' }

local file = fs.open('out.txt', 'w')
process.spawn { '/bin/ls', cwd = fs.cwd(), stdout = file.descriptor }

process.pid()

Returns the current process's PID.

process.path()

Returns the path to the executable for the current process.

process.kill(pid, signal)

Send a signal to a process. signal defaults to "SIGKILL" and can have any of the following values:

  • "SIGKILL": The process should exit.
  • "SIGINT": The user pressed Control+C.
  • "SIGHUP": The user closed the console window.
  • "SIGWINCH": The user resized the console window.

process.on(signal, callback)

Call callback when a given signal is received. signal can only be "SIGINT", "SIGHUP", or "SIGWINCH".

process.on('SIGINT', function()
  print('Shutting down...')
  os.exit()
end)

process.usage()

Returns a table describing the current process's resource usage with the following keys:

  • utime: User CPU time used, in microseconds.
  • stime: System CPU time used, in microseconds.
  • maxrss: Maximum resident set size.
  • ixrss: Integral shared memory size.
  • idrss: Integral unshared data size.
  • isrss: Integral unshared stack size.
  • minflt: Page reclaims (soft page faults).
  • majflt: Page faults (hard page faults).
  • nswap: Swaps.
  • inblock: Block input operations.
  • oublock: Block output operations.
  • msgsnd: IPC messages sent.
  • msgrcv: IPC messages received.
  • nsignals: Signals received.
  • nvcsw: Voluntary context switches.
  • nivcsw: Involuntary context switches.

process.title(value)

Change the current process's title to value, if present. Returns the existing title. I think this only works on Windows.