| 1 | #!/bin/bash |
| 2 | # Desc: Get timestamp in nanoseconds |
| 3 | |
| 4 | yell() { echo "$0: $*" >&2; } #o Yell, Die, Try Three-Fingered Claw technique |
| 5 | die() { yell "$*"; exit 111; } #o Ref/Attrib: https://stackoverflow.com/a/25515370 |
| 6 | try() { "$@" || die "cannot $*"; } #o |
| 7 | timeEpochNS() { |
| 8 | # Desc: Get epoch nanoseconds |
| 9 | # Usage: timeEpochNS |
| 10 | # Version 0.2.3 |
| 11 | # Input: arg1: 'date'-parsable timestamp string (optional) |
| 12 | # Output: Nanoseconds since 1970-01-01 |
| 13 | # Depends: date 8, cut 8, yell() |
| 14 | # Ref/Attrib: Force base 10 Bash arith with '10#'. https://stackoverflow.com/a/24777667 |
| 15 | local argTime timeCurrent timeInput timeEpochFloat timeEpochInt |
| 16 | local timeEpochNsFrac timeEpochNs |
| 17 | |
| 18 | argTime="$1"; |
| 19 | |
| 20 | # Get Current Time |
| 21 | timeCurrent="$(date --iso-8601=ns)"; # Produce `date`-parsable current timestamp with resolution of 1 nanosecond. |
| 22 | |
| 23 | # Decide to parse current or supplied time |
| 24 | ## Check if time argument empty |
| 25 | if [[ -z "$argTime" ]]; then |
| 26 | ## T: Time argument empty, use current time |
| 27 | timeInput="$timeCurrent"; |
| 28 | else |
| 29 | ## F: Time argument exists, validate time |
| 30 | if date --date="$argTime" 1>/dev/null 2>&1; then |
| 31 | ### T: Time argument is valid; use it |
| 32 | timeInput="$argTime"; |
| 33 | else |
| 34 | ### F: Time argument not valid; exit |
| 35 | yell "ERROR:Invalid time argument supplied. Exiting."; exit 1; |
| 36 | fi; |
| 37 | fi; |
| 38 | # Construct and deliver nanoseconds since 1970-01-01 |
| 39 | timeEpochFloat="$(date --date="$timeInput" +%s.%N)"; # Save ssss.NNNNNNNNN |
| 40 | timeEpochInt="$(echo "$timeEpochFloat" | cut -d. -f1)"; # Get ssss |
| 41 | timeEpochNsFrac="$(echo "$timeEpochFloat" | cut -d. -f2)"; # Get NNNNNNNNN |
| 42 | timeEpochNs="$(( (10#"$timeEpochInt" * 10**9) + (10#"$timeEpochNsFrac") ))"; |
| 43 | echo "$timeEpochNs"; |
| 44 | } # Nanoseconds since 1970-01-01 |
| 45 | |
| 46 | #==BEGIN sample code== |
| 47 | echo "It's been $(timeEpochNS) nanoseconds since 1970-01-01."; |
| 48 | echo "It's been $(timeEpochNS "10 years ago") nanoseconds since 10 years ago."; |
| 49 | echo "It's been $(timeEpochNS "2003-02-01T08:59:15-05:00") nanoseconds since contact lost with STS-107."; |
| 50 | #==END sample code== |
| 51 | |
| 52 | # Author: Steven Baltakatei Sandoval |
| 53 | # License: GPLv3+ |