jrnltimediff

#!/bin/bash

# This script comes with ABSOLUTELY NO WARRANTY, use at own risk
# Copyright (C) 2017 Osiris Alejandro Gomez <osiris@gcoop.coop>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.

die() {
  echo "ERROR $1"
  exit 1
}

[[   -z "$1" ]] && die "EMPTY FILE $1"
[[ ! -e "$1" ]] && die "NOT FOUND FILE $1"

[[ ! -z "$2" ]] && D2="$2"

D1=$(head -1 "$1" | cut -c -16)

[[ -z "$D1" ]] && die "@ 00:00 hs"

VALID_DATE=$(echo "$D1" | egrep -o "[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}")

[[ -z "$VALID_DATE" ]] && exit 1
[[ "$D1" != "$VALID_DATE" ]] && exit 1

E1=$(date --date="$D1" +%s)

if [[ -z "$D2" ]]
then
  E2=$(date --date='now' +%s)
else
  DD=$(echo "$D1" | cut -c -10)
  E2=$(date --date="$DD $D2" +%s)
fi

EE=$((E2-E1))
HM=$(date -d "1970-01-01 $EE seconds" +%H:%M)
echo "@ $HM hs"