不能使用bash作为Sensu插件获取jstat指标

这是输出示例：

demo.server1.sms.jstat.eden 24.34   0
demo.server1.lcms.jstat.eden    54.92   0
demo.server1.lms.jstat.eden 89.49   0
demo.server1.tms.jstat.eden 86.05   0

但当Sensu-client运行此脚本时,它会返回

Could not attach to 8584
Could not attach to 8588
Could not attach to 17141
Could not attach to 8628
demo.server1.sms.jstat.eden     0
demo.server1.lcms.jstat.eden    0
demo.server1.lms.jstat.eden     0
demo.server1.tms.jstat.eden     0

以下是check_cron.json的示例

{
  "checks": {
    "jstat_metrics": {
      "type": "metric","handlers": ["graphite"],"command": "/etc/sensu/plugins/jstat-metrics.sh","interval": 5,"subscribers": [ "webservers" ]
    }
  }
}

还有我的bash脚本

jvm_list=("sms:$sms" "lcms:$lcms" "lms:$lms" "tms:$tms" "ums:$ums")
for jvm_instance in ${jvm_list[@]}; do
    project=${jvm_instance%%:*}
    pid=${jvm_instance#*:}
        if [ "$pid" ]; then
          metric=`jstat -gc $pid|tail -n 1`
          output=$output$'n'"demo.server1.$project.jstat.eden"$'t'`echo $metric |awk '{ print $3}'`$'t0'
        fi
done
echo "$output"

我发现问题是jstat,我试图编写完整的jstat路径,如/usr/lib/jvm/java-1.7.0-openjdk.x86_64/bin/jstat -gc $pid | tail -n 1但它没有’帮忙！

顺便说一句,如果我将评论这一行,输出像“无法附加到8584”消失！