node.js execute system command synchronously

Node.js (since version 0.12 - so for a while) supports execSync:

child_process.execSync(command[, options])

You can now directly do this:

const execSync = require('child_process').execSync;code = execSync('node -v');

and it'll do what you expect. (Defaults to pipe the i/o results to the parent process). Note that you can also spawnSync now.

See execSync library.

It's fairly easy to do with node-ffi. I wouldn't recommend for server processes, but for general development utilities it gets things done. Install the library.

npm install node-ffi

Example script:

var FFI = require("node-ffi");var libc = new FFI.Library(null, {  "system": ["int32", ["string"]]});var run = libc.system;run("echo $USER");

[EDIT Jun 2012: How to get STDOUT]

var lib = ffi.Library(null, {    // FILE* popen(char* cmd, char* mode);    popen: ['pointer', ['string', 'string']],    // void pclose(FILE* fp);    pclose: ['void', [ 'pointer']],    // char* fgets(char* buff, int buff, in)    fgets: ['string', ['string', 'int','pointer']]});function execSync(cmd) {  var    buffer = new Buffer(1024),    result = "",    fp = lib.popen(cmd, 'r');  if (!fp) throw new Error('execSync error: '+cmd);  while(lib.fgets(buffer, 1024, fp)) {    result += buffer.readCString();  };  lib.pclose(fp);  return result;}console.log(execSync('echo $HOME'));

Use ShellJS module.

exec function without providing callback.

Example:

var version = exec('node -v').output;