bash /usr/bin/time --format 输出经过的时间（以毫秒为单位）
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/usr/bin/time --format output elapsed time in milliseconds
提问by Preexo
I use the /usr/bin/time program to measure the time for a command. with the --format parameter i can format the output. e.g.
我使用 /usr/bin/time 程序来测量命令的时间。使用 --format 参数，我可以格式化输出。例如
/usr/bin/time -f "%e" ls
is there a way to output a bigger accuracy of the elapsed seconds? or just output milliseconds, not seconds?
有没有办法输出经过秒数的更大精度？还是只输出毫秒，而不是秒？
In the manual of /usr/bin/time it only says something about seconds, but maybe there is a way and someone can help me... thanks!
在 /usr/bin/time 的手册中，它只说了几秒钟，但也许有办法，有人可以帮助我……谢谢！
EDIT: I know about the bash command "time" which uses the format of the environment variable "TIMEFORMAT". sorry, but i don't wanna change that env-var... seems to risky to me, solution should be something that doesn't change the running system at all :)
编辑：我知道使用环境变量“TIMEFORMAT”格式的 bash 命令“time”。对不起，但我不想改变那个 env-var ......对我来说似乎有风险，解决方案应该是根本不会改变正在运行的系统的东西:)
回答by devnull
One possibility is to use the datecommand:
一种可能性是使用date命令：
ts=$(date +%s%N) ; my_command ; tt=$((($(date +%s%N) - $ts)/1000000)) ; echo "Time taken: $tt milliseconds"
%Nshould return nanoseconds, and 1 millisecond is 1000000 nanosecond, hence by division would return the time taken to execute my_commandin milliseconds.
%N应该返回nanoseconds，1 毫秒是 1000000 纳秒，因此除法将返回my_command以毫秒为单位执行的时间。
NOTEthat the %Nis not supported on all systems, but most of them.
请注意， %N并非所有系统都支持 ，但大多数系统都支持。
回答by Infineight
For convenience I made devnull's answer into a script (I named it millisecond-time).
为方便起见，我将 devnull 的答案制作成了一个脚本（我将其命名为毫秒时间）。
#!/bin/bash
ts=$(date +%s%N) ; $@ ; tt=$((($(date +%s%N) - $ts)/1000000)) ; echo "Time taken: $tt milliseconds"
I put the script in /usr/local/bin.
Gave it execute rights chmod +x /usr/local/bin/millisecond-time.
Now I can use it like this: millisecond-time my_command
我把脚本放在/usr/local/bin.
给它执行权限chmod +x /usr/local/bin/millisecond-time。
现在我可以这样使用它：millisecond-time my_command
P.s. This would be a comment if I had the rep'.
Ps 如果我有代表，这将是一个评论。
