LogFilter

Print lines from log files which match the given date range and severity
level.

Use GNU date to convert dates into datestamps, then use AWK to filter
lines by field -- an overgrown version of this one-liner:

    awk \
      -v after=$(date --date=today-3days +%Y-%m-%d) \
      -v before=$(date --date=today+1day +%Y-%m-%d) \
      -v level='EMERG|ALERT|CRITICAL|ERROR|WARNING|NOTICE' \
      '$1 > after && $1 <= before && $3 ~ level' \
      ${logfiles}

The goal is to produce a digestible screenful of the most recent and
most urgent log messages.

Run-time requirements: Python 3.9+, GNU date, AWK

Copyright 2023, 2024 Dylan Maltby

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.