I have a problem, I need to read from a console output in real time. I have a file that I need to execute, tried doing something like this test.exe > text.txt but when I try to read while exe file is running I can't see anything until exe finishes and write all lines in the same time. I need to do this using node.js
2 Answers
You should be able to use child_process.spawn() to start the process and read from its stdout/stderr streams:
var spawn = require('child_process').spawn;
var proc = spawn('test.exe');
proc.stdout.on('data', function(data) {
process.stdout.write(data);
});
proc.stderr.on('data', function(data) {
process.stderr.write(data);
});
proc.on('close', function(code, signal) {
console.log('test.exe closed');
});
Comments
test.exe probably buffers it's output.
- Disable buffering on redirected stdout Pipe (Win32 API, C++)
- windows console program stdout is buffered when using pipe redirection
- Python C program subprocess hangs at "for line in iter"
You can try to run it with spawn, or with a pseudo tty
const spawn = require('child_process').spawn;
const type = spawn('type.exe');
type.stdout.on('data', (data) => {
console.log(`stdout: ${data}`);
});
type.stderr.on('data', (data) => {
console.log(`stderr: ${data}`);
});
type.on('close', (code) => {
console.log(`child process exited with code ${code}`);
});
execFile('test.exe > test.txt',function(err, stdout, stderr) { console.log(stdout); }).on('data', function (stdout){ sendResponse(); console.log(stdout.toString() + "stdout"); });I need to read from test.txt while this is running and send it as a response to post request from client side. I need to do something like progress bar for that test.exe program.