linux - Shell 脚本(使用 top 命令)在 cronjob 中不起作用

Question

Cron 表达式:

# m h dom mon dow 命令 */1 * * * */home/sysadmin/sample.sh

Shell脚本内容:

#!/bin/bash
clear
Vardate=`date`
topresult=`top -n 1| grep Cpu`
# CPUStatus=$Vardate"\t"$topresult
# echo $CPUStatus >> /tmp/data.log
echo $Vardate"   "$topresult >> /tmp/data.log

当我手动执行脚本时，我得到了所需的输出。这是:

Wed Sep 23 02:42:47 MDT 2015   Cpu(s): 0.3%us, 0.3%sy, 0.0%ni, 99.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st

但是当cronjob执行时，输出如下:

Wed Sep 23 02:42:47 MDT 2015 

这可能是什么原因？

Answer 1

使用top的“批处理”模式。

替换:

topresult=`top -n 1| grep Cpu`

与:

topresult=`top -b -n 1| grep Cpu`

-b : Batch mode operation Starts top in 'Batch mode', which could be useful for sending output from top to other programs or to a file. In this mode, top will not accept input and runs until the iterations limit you've set with the '-n' command-line option or until killed.

来源:http://linux.die.net/man/1/top