unitproc/bkt-dateShort

   1 #!/bin/bash
   2 # Desc: Template to display date
   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 dateShort(){
   8     # Desc: Date without separators (YYYYmmdd)
   9     # Usage: dateShort ([str date])
  10     # Version: 1.1.2
  11     # Input: arg1: 'date'-parsable timestamp string (optional)
  12     # Output: stdout: date (ISO-8601, no separators)
  13     # Depends: bash 5.0.3, date 8.30, yell()
  14     local argTime timeCurrent timeInput dateCurrentShort
  15
  16     argTime="$1";
  17     # Get Current Time
  18     timeCurrent="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
  19     # Decide to parse current or supplied date
  20     ## Check if time argument empty
  21     if [[ -z "$argTime" ]]; then
  22         ## T: Time argument empty, use current time
  23         timeInput="$timeCurrent";
  24     else
  25         ## F: Time argument exists, validate time
  26         if date --date="$argTime" 1>/dev/null 2>&1; then
  27             ### T: Time argument is valid; use it
  28             timeInput="$argTime";
  29         else
  30             ### F: Time argument not valid; exit
  31             yell "ERROR:Invalid time argument supplied. Exiting."; exit 1;
  32         fi;
  33     fi;
  34     # Construct and deliver separator-les date string
  35     dateCurrentShort="$(date -d "$timeInput" +%Y%m%d)"; # Produce separator-less current date with resolution 1 day.
  36     echo "$dateCurrentShort";
  37 } # Get YYYYmmdd
  38
  39 #==BEGIN sample code==
  40 echo "The current day is          :$(dateShort)";
  41 echo "Contact lost with STS-107 on:$(dateShort "2003-02-01T08:59:15-05:00")";
  42 echo "Bitcoin started on          :$(dateShort "@1231006505")";
  43 #==END sample code==
  44
  45 # Author: Steven Baltakatei Sandoval
  46 # License: GPLv3+