add err.command on exec() failures

[tj]

sometimes you get these gems "Command failed:", would be nice to not have to manually augment the error

[trevnorris]

Can you provide an example?

[tj]

contrived example but for stuff like this it may be nice to see if there's no stderr and then use the command as the message, or since that's sort of awkward it would at least be nice to have err.command so there's something to go on

var exec = require('child_process').exec;

exec('cat /foo 2> /dev/null', function(err){
  throw err;
});

  throw err;
        ^
Error: Command failed: 
    at ChildProcess.exithandler (child_process.js:661:12)
    at ChildProcess.EventEmitter.emit (events.js:101:17)
    at maybeClose (child_process.js:773:16)
    at Socket.<anonymous> (child_process.js:993:11)
    at Socket.EventEmitter.emit (events.js:98:17)
    at Pipe.close (net.js:459:12)

[indutny]

See ^

[tj]

awesome! thanks man

[tj]

oh sorry thought that was master haha

[indutny]

Well, I don't think that we can land it in v0.10.