使用appium在android7.0真机上测试程序时报错command failed shell “ps ‘uiautomator’”的解决方式
appium版本1.4.16，在android7.0真机上测试程序时会报错：command failed shell “ps ‘uiautomator’”。

1、找到appium的安装目录下的adb.js文件，目录为：Appium\node_modules\appium\node_modules\appium-adb\lib
2、打开adb.js，找到如下代码：

ADB.prototype.shell = function (cmd, cb) {
  if (cmd.indexOf('"') === -1) {
    cmd = '"' + cmd + '"';
  }
  var execCmd = 'shell ' + cmd;
  this.exec(execCmd, cb);
};

在这段代码下面加入这段代码：

ADB.prototype.shell_grep = function (cmd, grep, cb) {
  if (cmd.indexOf('"') === -1) {
    cmd = '"' + cmd + '"';
  }
  var execCmd = 'shell ' + cmd + '| grep ' + grep;
  this.exec(execCmd, cb);
};

再找到如下代码：

ADB.prototype.getPIDsByName = function (name, cb) {
  logger.debug("Getting all processes with '" + name + "'");
  this.shell("ps '" + name + "'", function (err, stdout) {
    if (err) return cb(err);
    stdout = stdout.trim();
    var procs = [];
    var outlines = stdout.split("\n");
    outlines.shift();
    _.each(outlines, function (outline) {
      if (outline.indexOf(name) !== -1) {
        procs.push(outline);
      }
    });
    if (procs.length < 1) {
      logger.debug("No matching processes found");
      return cb(null, []);
    }
    var pids = [];
    _.each(procs, function (proc) {
      var match = /[^\t ]+[\t ]+([0-9]+)/.exec(proc);
      if (match) {
        pids.push(parseInt(match[1], 10));
      }
    });
    if (pids.length !== procs.length) {
      var msg = "Could not extract PIDs from ps output. PIDS: " +
                JSON.stringify(pids) + ", Procs: " + JSON.stringify(procs);
      return cb(new Error(msg));
    }
    cb(null, pids);
  });
};

把这段代码注释掉，用如下代码代替：

ADB.prototype.getPIDsByName = function (name, cb) {
  logger.debug("Getting all processes with '" + name + "'");
  this.shell_grep("ps", name, function (err, stdout) {
    if (err) {
      logger.debug("No matching processes found");
      return cb(null, []);
    }
    var pids = [];
    _.each(procs, function (proc) {
    var match = /[^\t ]+[\t ]+([0-9]+)/.exec(proc);
    if (match) {
    pids.push(parseInt(match[1], 10));
    }
    });
    if (pids.length !== procs.length) {
      var msg = "Could not extract PIDs from ps output. PIDS: " +
      JSON.stringify(pids) + ", Procs: " + JSON.stringify(procs);
      return cb(new Error(msg));
    }
    cb(null, pids);
  });
};

3、重启appium,完美解决问题

原文出自：
https://blog.csdn.net/pjl6523853/article/details/72886048