bash脚本来侦听Shell命令输出 [英] Bash Script To Listen For Shell Command Output

问题描述

快速的问题。我怎么会去有一个shell脚本执行以下操作：

Quick question. How would I go about having a shell script to do the following:

• 执行UNIX命令（pmset -g PS）来检查脚本每5秒的输出，然后如果该命令的输出下降到低于说40％（例如输出的是：交流电源'从Currenty绘图
  -iBox 100％;充电'），然后为它在UNIX shell脚本...

任何帮助将是非常美联社preciated。

Any help would be much appreciated.

推荐答案

修改，为2.05猛砸的后来的：

Edit, for Bash 2.05 and later:

#!/bin/bash
tab=$'\t'
while true  # run forever, change to stop on some condition
do
    threshold=100
    until (( threshold < 40 ))
    do
        sleep 5
        result=$(pmset -g ps)
        threshold="${result#*iBox$tab}"
        threshold="${threshold%\%*}"
    done
    shell_script
done

原来，为猛砸3.2及更高版本：

#!/bin/bash
pattern='[0-9]+'    # works if there's only one sequence of digits in the output, a more selective pattern is possible if needed
while true  # run forever, change to stop on some condition
do
    threshold=100
    until (( threshold < 40 ))
    do
        sleep 5
        result=$(pmset -g ps)
        [[ $result =~ $pattern ]]
        threshold=${BASH_REMATCH[1]}
    done
    shell_script
done

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