var command = require('command');
 
command.open('/some/directory/path')
    .on('stdout', command.writeTo(process.stdout))
    .on('stderr', command.writeTo(process.stderr))
    .chdir('..')
    .exec('ls')
    .then(function() {
        var stdout = this.lastOutput.stdout;
        if (! stdout.trim().length) {
            console.warn('No files found!');
        }
    });