await-shell

await-shell

Library for calling POSIX-style shell commands cross-platform. Automatically translates commands for Windows support out of the box.

shell.run() returns a Promise that will resolve or reject to an object containing process information of type SpawnResult:

export interface SpawnResult {
  code: number | null;
  stdout: string;
  stderr: string;
}

Pattern

/**
 * Create a new process where shells will run.
 */
const shell = createShell();

/**
 * Read the exit code, stdout, and stderr from shell.run().
 * 
 * Note: POSIX-like syntax works on Windows! See "Specification" below.
 */
const { code, stdout, stderr } = await shell.run("cp -rf src dest && yarn --cwd dest some-command");

/**
 * Run sequential commands.
 */
await shell.run(
  "cd dir && yarn do_stuff",
  "cd otherDir && yarn do_stuff"
);

Override per-platform

You can override the command to run per-platform in shell.run(...).

const shell = createShell();

/**
 * All process.platform types are supported, i.e. "win32" and "darwin".
 * 
 * "posix" matches "linux" and "darwin".
 */ 
const { code, stdout, stderr } = await shell.run({
  win32: "...",
  posix: "..."
});

Custom options

You can pass custom spawn options to createShell({ ... }).

/**
 * Disable logging of commands and pass custom spawn options. 
 */
const customShell = createShell({
  log: false,
  // Custom process.spawn() options.
  stdio: 'inherit',
  // ...
});

Specification

This section explains how shell command strings (like "cd dir/") are supported on Windows, as well as translations for specific commands.

Shell support

POSIX	Windows
Detached	Not detached
my-cmd [...args]	cmd.exe /d /s /c my-cmd [...args]

Specific commands

POSIX	Windows
cp -rf [src] dest]	xcopy /E /S /G /Q /Y [src] [dest]
pkill [pid]	taskkill /T /F /pid [pid]
ln [link] [target]	mklink [link] [target]

Footnotes

Quotes on Windows

You should use single quotes in your strings if possible for interoperability with Windows.

const { code, stdout, stderr } = await shell.run("my-cmd 'a string'");