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e9c166c0 SBS |
1 | #!/bin/bash |
2 | # Desc: Get timestamp in nanoseconds | |
3 | ||
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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 | |
4caeddd7 | 7 | timeEpochNS() { |
e9c166c0 | 8 | # Desc: Get epoch nanoseconds |
4caeddd7 | 9 | # Usage: timeEpochNS |
d29fa44f | 10 | # Version 0.2.3 |
6ed44731 | 11 | # Input: arg1: 'date'-parsable timestamp string (optional) |
e9c166c0 | 12 | # Output: Nanoseconds since 1970-01-01 |
d29fa44f | 13 | # Depends: date 8, cut 8, yell() |
6ed44731 | 14 | # Ref/Attrib: Force base 10 Bash arith with '10#'. https://stackoverflow.com/a/24777667 |
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15 | local argTime timeCurrent timeInput timeEpochFloat timeEpochInt |
16 | local timeEpochNsFrac timeEpochNs | |
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17 | |
18 | argTime="$1"; | |
19 | ||
20 | # Get Current Time | |
d29fa44f | 21 | timeCurrent="$(date --iso-8601=ns)"; # Produce `date`-parsable current timestamp with resolution of 1 nanosecond. |
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22 | |
23 | # Decide to parse current or supplied time | |
24 | ## Check if time argument empty | |
25 | if [[ -z "$argTime" ]]; then | |
26 | ## T: Time argument empty, use current time | |
d29fa44f | 27 | timeInput="$timeCurrent"; |
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28 | else |
29 | ## F: Time argument exists, validate time | |
30 | if date --date="$argTime" 1>/dev/null 2>&1; then | |
31 | ### T: Time argument is valid; use it | |
d29fa44f | 32 | timeInput="$argTime"; |
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33 | else |
34 | ### F: Time argument not valid; exit | |
35 | yell "ERROR:Invalid time argument supplied. Exiting."; exit 1; | |
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36 | fi; |
37 | fi; | |
6ed44731 | 38 | # Construct and deliver nanoseconds since 1970-01-01 |
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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"; | |
aec895f5 | 44 | } # Nanoseconds since 1970-01-01 |
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45 | |
46 | #==BEGIN sample code== | |
4caeddd7 | 47 | echo "It's been $(timeEpochNS) nanoseconds since 1970-01-01."; |
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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."; | |
e9c166c0 | 50 | #==END sample code== |
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51 | |
52 | # Author: Steven Baltakatei Sandoval | |
53 | # License: GPLv3+ |