tailsince [N minutes] <file> [file..]

tailsince.sh

#!/usr/bin/env bash
period=$1
shift
for file in $@; do
  timeshift=$(date -d"-${period} minutes" +%s);
  while read -u3 date time line; do
    epoch_timestamp=$(date -d"${date} ${time}" +%s);
    if [[ ${timeshift} -lt ${epoch_timestamp} ]]; then
      echo "${date} ${time} ${line}";
    else
      break;
    fi;
  done 3< <(tac ${file}) | tac
  shift
  if [[ -n $1 ]]; then echo -- "----- $1 -----"; fi
done

Currently with perp log format

2021-11-11 08:24:50.490544 nginx: ok
^--$date-^ ^-----$time---^ ^-$line->