shell 输出Unix时间戳

秒级时间戳： 

$ echo $(date +%s)
1681983716

毫秒/微秒/纳秒 时间戳：

$ echo $(($(date +%s%N)/1000000))
1681984600895
$ echo $(($(date +%s%N)/1000))
1681984779486536
$ date +%s%N
1681984840382296459

可以把命令保存到一个shell脚本中方便后续使用

#!/usr/bin/env bashshow_help() {cat <<EOT
Usage:timestamp [options]Show current unix timestamp, the duration since 1970-01-01 00:00:00 UTC, default in secondsOptions:-s             Timestamp in seconds-m, --ms       Timestamp in milliseconds-u, --us       Timestamp in microseconds-n, --ns       Timestamp in nanoseconds
EOT
}if [ $# -lt 1 ]; thendate +%sexit 0
ficase $1 in
-s)date +%s;;
-m|--ms)echo $(($(date +%s%N)/1000000));;
-u|--us)echo $(($(date +%s%N)/1000));;
-n|--ns)date +%s%N;;
*)printf "invalid option: %s\\n" "$1" >&2show_helpexit 1;;
esac

Example：

$ chmod +x timestamp.sh
$ ./timestamp.sh
1681988240
$ ./timestamp.sh -m
1681988247134
$ ./timestamp.sh --us
1681988251839104
$ ./timestamp.sh --ns
1681988254563233455