差異處
這裏顯示兩個版本的差異處。
Both sides previous revision 前次修改 下次修改 | 前次修改 | ||
linux:shell_script:execution_time_measurement [2016/07/02 11:24] tony |
linux:shell_script:execution_time_measurement [2016/07/02 17:09] tony |
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行 1: | 行 1: | ||
+ | {{tag>Linux ShellScript}} | ||
====== 測量執行時間 ====== | ====== 測量執行時間 ====== | ||
===== time command ===== | ===== time command ===== | ||
行 22: | 行 23: | ||
echo $END | echo $END | ||
+ | </code> | ||
+ | ===== date command ===== | ||
+ | 與$SECONDS方法類似,但可以精確到nano second(10^-9)的差距: | ||
+ | <code bash> | ||
+ | START=`date +%s%N` | ||
+ | echo $START | ||
+ | |||
+ | # some operations | ||
+ | sleep 1 | ||
+ | |||
+ | END=`date +%s%N` | ||
+ | echo $END | ||
+ | |||
+ | END=$(($END - $START)) | ||
+ | echo $END | ||
+ | |||
+ | # 換算為millisecond | ||
+ | END=$(($END / 1000000)) | ||
+ | echo $END | ||
+ | </code> | ||
+ | |||
+ | output: | ||
+ | |||
+ | <code bash> | ||
+ | 1467450293336690574 | ||
+ | 1467450294338625297 | ||
+ | 1001934723 | ||
+ | 1001 | ||
</code> | </code> | ||
===== Reference ===== | ===== Reference ===== |