#!/bin/bash
#
#    10-sysinfo - generate the system information
#    Copyright (c) 2013 Nick Charlton
#
#    Authors: Nick Charlton <hello@nickcharlton.net>
#    Modified by Oitibs: https://oitibs.com/?s=Debian+Dynamic+MOTD
#    Modified by Leitbogioro: https://github.com/leitbogioro/
#                             https://www.zhihu.com/column/originaltechnic
#
#    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 2 of the License, or
#    (at your option) 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, write to the Free Software Foundation, Inc.,
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
date=`date`
load=`cat /proc/loadavg | awk '{print $1}'`
root_usage=`df -h / | awk '/\// {print $(NF-1)}'`
memory_usage=`free -m | awk '/Mem:/ { total=$2; used=$3 } END { printf("%3.1f%%", used/total*100)}'`
 
swap_usage=`free -m | awk '/Swap/ { printf("%3.1f%%", $3/$2*100) }'`
users=`users | wc -w`
time=`uptime | grep -ohe 'up .*' | sed 's/,/\ hours/g' | awk '{ printf $2" "$3 }'`
processes=`ps aux | wc -l`
localip=`hostname -I | awk '{print $1}'`

IPv4=`timeout 1 dig -4 TXT +short o-o.myaddr.l.google.com @ns1.google.com | sed 's/\"//g'`
IPv6=`timeout 1 dig -6 TXT +short o-o.myaddr.l.google.com @ns1.google.com | sed 's/\"//g'`
# IP_Check=$(echo $IPv4 | awk -F. '$1<255&&$2<255&&$3<255&&$4<255{print "isIPv4"}')
IP_Check="$IPv4"
if expr "$IP_Check" : '[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*$' >/dev/null; then
  for i in 1 2 3 4; do
    if [ $(echo "$IP_Check" | cut -d. -f$i) -gt 255 ]; then
      echo "fail ($IP_Check)"
      exit 1
    fi
  done
  IP_Check="isIPv4"
else
  :
fi

if [[ "${IP_Check}" == "isIPv4" ]] && [[ -z ${IPv6} ]]; then
  IPv6="N/A"
fi

if [[ -z ${IPv4} ]] && [[ -z !${IPv6} ]]; then
  IPv4="N/A"
fi

if [[ "${localip}" == "${IPv4}" ]] || [[ "${localip}" == "${IPv6}" ]]; then
  # localip=`ip -o a show | grep -w "lo" | grep -w "inet" | cut -d ' ' -f7 | awk '{split($1, a, "/"); print $2 "" a[1]}'`
  localip=`cat /etc/hosts | grep "localhost" | sed -n 1p | awk '{print $1}'`
fi

echo " System information as of $date"
echo
printf "%-30s%-15s\n" " System Load:" "$load"
printf "%-30s%-15s\n" " Private IP address:" "$localip"
printf "%-30s%-15s\n" " Public IPv4 address:" "$IPv4"
printf "%-30s%-15s\n" " Public IPv6 address:" "$IPv6"
printf "%-30s%-15s\n" " Memory Usage:" "$memory_usage"
printf "%-30s%-15s\n" " Usage On /:" "$root_usage"
printf "%-30s%-15s\n" " Swap Usage:" "$swap_usage"
printf "%-30s%-15s\n" " Local Users:" "$users"
printf "%-30s%-15s\n" " Processes:" "$processes"
printf "%-30s%-15s\n" " System Uptime:" "$time"
echo