在node.js中使用子进程，在命令完成时调用函数

Question

I am making a program in which I need to execute some linux command through node.js.

like this

final_command.stdout.on('data', function(data) { 
    fs.writeFile(dates+'.html', data, function(err){
        if(err){
            return console.error(err);
        }
    });
});

final_command.stderr.on('data', function(data) { 
    console.log('stderr: '+data);
});

final_command.on('exit', function(code) { 

}); 

Here I am saving the output to a HTML file.

Now to run the other part of the program

Should I put it in the final_command.on part or how can I call a function in that part?

I know that's a lame question but still.

Answer 1

The question 'Should I put it in the final_command.on part or how can I call a function in that part?' is unclear. Do you mean to ask how to fill-in the final_command? If so, here is how you will do it.

var spawn = require('child_process').spawn;
var fs = require('fs');
var dates = 'dates';

var command = 'ls';
var final_command = spawn(command);

final_command.stdout.on('data', function childoutdata) { 
    fs.writeFile(dates+'.html', data, function childdatawrite(err){
        if(err){
            return console.error(err);
        }
    });
});

final_command.stderr.on('data', function(data) { 
    console.log('stderr: '+data);
});

final_command.on('exit', function childexit(code) { 

});

If the question is how and when you continue the work after the file operation, it depends: If the child process action, data arrival and writing into the file should precede everything, then you should write your rest of the code in childdatawrite. If the child process is all what you care about, then you should write your rest of the code in childexit. If the rest of the code can run out of sync with the child business, then can place your code outside of the current block.

Hope this helps.