我的方法：

protected String execCommand(String command) throws IOException {
    String line = null;
    if (command.length() > 0) {
        Process child = Runtime.getRuntime().exec(command);
        InputStream lsOut = child.getInputStream();
        InputStreamReader r = new InputStreamReader(lsOut);
        BufferedReader in = new BufferedReader(r);

        String readline = null;
        while ((readline = in.readLine()) != null) {
            line = line + readline;
        }
    }

    return line;
}

如果我正在调用一些猫文件| grep asd,我得到了预期的结果.但并非所有命令都能正常工作.例如：

cat /proc/cpuinfo | wc -l

或这个：

cat /proc/cpuinfo | grep "model name" | head -n 1 | awk -F":" '{print substr($2,2,length($2))}

该方法将返回null.我猜这个问题取决于输出格式化命令,如head,tail,wc等.我如何解决这个问题并获得输出的最终结果？