Run all required rsnapshot intervals based on the date they were last run

run-rsnapshot

#!/bin/bash

CONF_FILE=/etc/rsnapshot.conf

if [ $# -lt 1 ]
then
  echo "Usage: $0 interval1:dateformat1 interval2:dateformat2 ..." >&2
  echo >&2
  echo "  Where intervaln is an rsnapshot retain interval and dateformatn is a" >&2
  echo "  format letter to be passed to date. If the intervaln.0 ctime formatted" >&2
  echo "  with dateformatn differs to the current date formatted with dateformatn" >&2
  echo "  the backup will be run." >&2
  echo >&2
  echo "  E.g.: $0 monthly:m weekly:W daily:j" >&2
  exit 1
fi

snapshot_root=`awk -F $'\t' '/^snapshot_root\t/ { print $2 }' "$CONF_FILE"`

if [ -z "$snapshot_root" ]
then
  echo "Could not find snapshot_root option in $CONF_FILE" >&2
  exit 1
fi

now=`date +%s`

for spec in "$@"
do
  interval=${spec%:*}
  format=${spec#*:*}
  current="$snapshot_root/$interval.0"
  run=0

  if [ ! -d "$current" ]
  then
    echo "No $interval.0 directory found"
    run=1
  else
    ctime=`stat --format=%Z "$snapshot_root/$interval.0"`
    ctime_formatted=`date "-d@$ctime" "+%$format"`
    now_formatted=`date "-d@$now" "+%$format"`

    if [ "$ctime_formatted" -ne "$now_formatted" ]
    then
      echo "Formatted change time of $interval.0 ($ctime_formatted) does not match current time ($now_formatted)"
      run=1
    else
      echo "Formatted change time of $interval.0 ($ctime_formatted) matches current time"
    fi
  fi

  if [ $run -eq 1 ]
  then
    echo "Running rsnapshot $interval"
    rsnapshot -c "$CONF_FILE" "$interval"
  else
    echo "Skipping rsnapshot $interval"
  fi
done