function onExec( error, stdout, stderr ) {
		var opts;
		if ( error ) {
			debug( 'Encountered an error when attempting to convert temporary input file: %s', error.message );
			return done( error );
		}
		debug( 'Command stdout: %s', stdout.toString() );
		debug( 'Command stderr: %s', stderr.toString() );

		debug( 'Successfully converted temporary input file.' );
		rm( inFile );

		debug( 'Reading temporary output file...' );
		opts = {
			'encoding': 'utf8'
		};
		readFile( outFile, opts, onRead );
	}
Callback invoked when a child process terminates.

@private
@param {(Error|null)} error - error object
@param {Buffer} stdout - standard output
@param {Buffer} stderr - standard error
@returns {void}