date
ls -l /etc/localtime
timedatectl
https://www.cnblogs.com/zhi-leaf/p/6282301.html

error_log 级别分为 debug, info, notice, warn, error, crit 默认为crit, 该级别在日志名后边定义格式如下：
error_log /your/path/error.log crit;
watch -n 1 'date -R'

curl -o /dev/null -s -w "time_namelookup: %{time_namelookup}\ntime_connect: %{time_connect}\ntime_appconnect: %{time_appconnect}\ntime_redirect: %{time_redirect}\ntime_pretransfer: %{time_pretransfer}\ntime_starttransfer: %{time_starttransfer}\ntime_total: %{time_total}\n" "http://www.baidu.com"

curl的时间
https://blog.cloudflare.com/a-question-of-timing/

vi ~/.curlrc
-w "dnslookup: %{time_namelookup} | connect: %{time_connect} | appconnect: %{time_appconnect} | pretransfer: %{time_pretransfer} | starttransfer: %{time_starttransfer} | total: %{time_total} | size: %{size_download}\n"

-w "time_namelookup: %{time_namelookup}\ntime_connect: %{time_connect}\ntime_appconnect: %{time_appconnect}\ntime_redirect: %{time_redirect}\ntime_pretransfer: %{time_pretransfer}\ntime_starttransfer: %{time_starttransfer}\ntime_total: %{time_total}\n"