beat.sh

#!/bin/sh
# Output the current time in Swatch Internet Time "beats"
# See: https://en.wikipedia.org/wiki/Swatch_Internet_Time
# Example output:
# @811


# Helper conversion function
# @param naive time as HH:MM:SS string
# @param [-c] to include "centibeats"
#
# Reference command:
#     TZ=UTC-1 date '+%H:%M:%S' | awk -F: '{printf("@%03d\n", ($3 + ($2 * 60) + ($1 * 3600)) / 86.4)}'
#
# Example usage:
#     to_beat 18:45:38
#     @781
#
#     to_beat 18:45:38 -c
#     @781.69
#
to_beat(){
    local format=''
    case "$2" in
       -c) format="@%06.2f\n";;
        *) format="@%03d\n";;
    esac

    echo "$1" | awk -F: \
        "{printf(\"$format\", (\$3 + (\$2 * 60) + (\$1 * 3600)) / 86.4)}"
}


# For backcompat, use UTC+1 with env var for current time, which does not
# observe daylight adjustments. This is unfortunately expressed as 'UTC-1'.
main(){
    to_beat $(TZ=UTC-1 date '+%H:%M:%S')
}

main

days_since.sh

#!/usr/bin/env bash
# Output the difference between two Unix timestamps in days
#
# Accepts the following arguments:
# - start timestamp  (default: unix epoch)
# - end timestamp    (default: current time)
# - output base      (default: 10)
# - output precision (default: 0)
#
# Example output:
# $ days_since.sh
# 17444
#
# $ days_since.sh 247881600 $(TZ=CET date '+%s') 16 3
# 38EF.BBE
#
# TODO: convert arg usage to flags so they can be parsed by getopt
# TODO: generalise to convert to other units of time (years, months, weeks, H:M:S, etc)

days() {
    local SECONDS=86400
    dc -e "10i $4 k $2 $1 - $SECONDS / $3o p"
}

main() {
    local start=${1:-0}
    local end=${2:-0}
    local base=${3:-10}
    local precision=${4:-0}

    [ $end == 0 ] && end=`date '+%s'`
    
    days $start $end $base $precision
}

main $@