shell高级技巧-获取进程的运行时长

在进程监控脚本中，我们通常需要根据脚本的参数来确定有哪些性能参数将被收集，当这些性能参数大于最高阈值或小于最低阈值时，监控脚本将根据实际的情况，采取预置的措施，如邮件通知、直接杀死进程等，这里我们给出的例子是收集进程运行时长性能参数。

ps命令的etime值将给出每个进程的运行时长，其格式主要为以下三种：
      1. minutes:seconds，如20:30
      2. hours:minutes:seconds，如1:20:30
      3. days-hours:minute:seconds，如2-18:20:30
      该脚本将会同时处理这三种格式的时间信息，并最终转换为进程所流经的分钟数。
      [[email protected] ~]# cat > test11.sh
      #!/bin/sh
      #1. 通过ps命令获取所有进程的pid、etime和comm数据。
      #2. 再通过grep命令过滤，只获取init进程的数据记录，这里我们可以根据需要替换为自己想要监控的进程名。
      #3. 输出结果通常为：1 09:42:09 init
      pid_string=`ps -eo pid,etime,comm | grep "init" | grep -v grep`
      #3. 从这一条记录信息中抽取出etime数据，即第二列的值09:42:09，并赋值给exec_time变量。
      exec_time=`echo $pid_string | awk '{print $2}'`
      #4. 获取exec_time变量的时间组成部分的数量，这里是3个部分，即时:分:秒，是上述格式中的第二种。
      time_field_count=`echo $exec_time | awk -F: '{print NF}'`
      #5. 从exec_time变量中直接提取分钟数，即倒数第二列的数据(42)。
      count_of_minutes=`echo $exec_time | awk -F: '{print $(NF-1)}'`
            
<span class="token comment">#6. 判断当前exec_time变量存储的时间数据是属于以上哪种格式。</span>
  <span class="token comment">#7. 如果是第一种，那么天数和小时数均为0。</span>
  <span class="token comment">#8. 如果是后两种之一，则需要继续判断到底是第一种还是第二种，如果是第二种，其小时部分将不存在横线(-)分隔符分隔天数和小时数，否则需要将这两个时间字段继续拆分，以获取具体的天数和小时数。对于第二种，天数为0.</span>
  <span class="token keyword">if</span> <span class="token punctuation">[</span> <span class="token variable">$time_field_count</span> -lt 3 <span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">then</span>
      count_of_hours<span class="token operator">=</span>0
      count_of_days<span class="token operator">=</span>0
  <span class="token keyword">else</span>
      count_of_hours<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $exec_time <span class="token operator">|</span> <span class="token function">awk</span> -F: <span class="token string">'{print <span class="token variable"><span class="token variable">$(</span>NF-2<span class="token variable">)</span></span>}'</span><span class="token variable">`</span></span>
      fields<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $count_of_hours <span class="token operator">|</span> <span class="token function">awk</span> -F- <span class="token string">'{print NF}'</span><span class="token variable">`</span></span>
      <span class="token keyword">if</span> <span class="token punctuation">[</span> <span class="token variable">$fields</span> -ne 1 <span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">then</span>
          count_of_days<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $count_of_hours <span class="token operator">|</span> <span class="token function">awk</span> -F- <span class="token string">'{print <span class="token variable">$1</span>}'</span><span class="token variable">`</span></span>
          count_of_hours<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $count_of_hours <span class="token operator">|</span> <span class="token function">awk</span> -F- <span class="token string">'{print <span class="token variable">$2</span>}'</span><span class="token variable">`</span></span>
      <span class="token keyword">else</span>
          count_of_days<span class="token operator">=</span>0
      <span class="token keyword">fi</span>
  <span class="token keyword">fi</span>
  <span class="token comment">#9. 通过之前代码获取的各个字段值，计算出该进程实际所流经的分钟数。</span>
  <span class="token comment">#10. bc命令是计算器命令，可以将echo输出的数学表达式计算为最终的数字值。</span>
  elapsed_minutes<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> <span class="token string">"<span class="token variable">$count_of_days*1440</span>+<span class="token variable">$count_of_hours*60</span>+<span class="token variable">$count_of_minutes</span>"</span> <span class="token operator">|</span> <span class="token function">bc</span><span class="token variable">`</span></span>
  <span class="token keyword">echo</span> <span class="token string">"The elapsed minutes of init process is"</span> <span class="token variable">$elapsed_minutes</span> <span class="token string">"minutes."</span>
  CTRL+D
  <span class="token punctuation">[</span>[email protected] ~<span class="token punctuation">]</span><span class="token comment"># ./test11.sh</span>
  The elapsed minutes of init process is 577 minutes.
           
   

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在进程监控脚本中，我们通常需要根据脚本的参数来确定有哪些性能参数将被收集，当这些性能参数大于最高阈值或小于最低阈值时，监控脚本将根据实际的情况，采取预置的措施，如邮件通知、直接杀死进程等，这里我们给出的例子是收集进程运行时长性能参数。

ps命令的etime值将给出每个进程的运行时长，其格式主要为以下三种：
      1. minutes:seconds，如20:30
      2. hours:minutes:seconds，如1:20:30
      3. days-hours:minute:seconds，如2-18:20:30
      该脚本将会同时处理这三种格式的时间信息，并最终转换为进程所流经的分钟数。
      [[email protected] ~]# cat > test11.sh
      #!/bin/sh
      #1. 通过ps命令获取所有进程的pid、etime和comm数据。
      #2. 再通过grep命令过滤，只获取init进程的数据记录，这里我们可以根据需要替换为自己想要监控的进程名。
      #3. 输出结果通常为：1 09:42:09 init
      pid_string=`ps -eo pid,etime,comm | grep "init" | grep -v grep`
      #3. 从这一条记录信息中抽取出etime数据，即第二列的值09:42:09，并赋值给exec_time变量。
      exec_time=`echo $pid_string | awk '{print $2}'`
      #4. 获取exec_time变量的时间组成部分的数量，这里是3个部分，即时:分:秒，是上述格式中的第二种。
      time_field_count=`echo $exec_time | awk -F: '{print NF}'`
      #5. 从exec_time变量中直接提取分钟数，即倒数第二列的数据(42)。
      count_of_minutes=`echo $exec_time | awk -F: '{print $(NF-1)}'`
            
<span class="token comment">#6. 判断当前exec_time变量存储的时间数据是属于以上哪种格式。</span>
  <span class="token comment">#7. 如果是第一种，那么天数和小时数均为0。</span>
  <span class="token comment">#8. 如果是后两种之一，则需要继续判断到底是第一种还是第二种，如果是第二种，其小时部分将不存在横线(-)分隔符分隔天数和小时数，否则需要将这两个时间字段继续拆分，以获取具体的天数和小时数。对于第二种，天数为0.</span>
  <span class="token keyword">if</span> <span class="token punctuation">[</span> <span class="token variable">$time_field_count</span> -lt 3 <span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">then</span>
      count_of_hours<span class="token operator">=</span>0
      count_of_days<span class="token operator">=</span>0
  <span class="token keyword">else</span>
      count_of_hours<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $exec_time <span class="token operator">|</span> <span class="token function">awk</span> -F: <span class="token string">'{print <span class="token variable"><span class="token variable">$(</span>NF-2<span class="token variable">)</span></span>}'</span><span class="token variable">`</span></span>
      fields<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $count_of_hours <span class="token operator">|</span> <span class="token function">awk</span> -F- <span class="token string">'{print NF}'</span><span class="token variable">`</span></span>
      <span class="token keyword">if</span> <span class="token punctuation">[</span> <span class="token variable">$fields</span> -ne 1 <span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token keyword">then</span>
          count_of_days<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $count_of_hours <span class="token operator">|</span> <span class="token function">awk</span> -F- <span class="token string">'{print <span class="token variable">$1</span>}'</span><span class="token variable">`</span></span>
          count_of_hours<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> $count_of_hours <span class="token operator">|</span> <span class="token function">awk</span> -F- <span class="token string">'{print <span class="token variable">$2</span>}'</span><span class="token variable">`</span></span>
      <span class="token keyword">else</span>
          count_of_days<span class="token operator">=</span>0
      <span class="token keyword">fi</span>
  <span class="token keyword">fi</span>
  <span class="token comment">#9. 通过之前代码获取的各个字段值，计算出该进程实际所流经的分钟数。</span>
  <span class="token comment">#10. bc命令是计算器命令，可以将echo输出的数学表达式计算为最终的数字值。</span>
  elapsed_minutes<span class="token operator">=</span><span class="token variable"><span class="token variable">`</span><span class="token keyword">echo</span> <span class="token string">"<span class="token variable">$count_of_days*1440</span>+<span class="token variable">$count_of_hours*60</span>+<span class="token variable">$count_of_minutes</span>"</span> <span class="token operator">|</span> <span class="token function">bc</span><span class="token variable">`</span></span>
  <span class="token keyword">echo</span> <span class="token string">"The elapsed minutes of init process is"</span> <span class="token variable">$elapsed_minutes</span> <span class="token string">"minutes."</span>
  CTRL+D
  <span class="token punctuation">[</span>[email protected] ~<span class="token punctuation">]</span><span class="token comment"># ./test11.sh</span>
  The elapsed minutes of init process is 577 minutes.