#!/bin/sh
#
#    Authors: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.

UpdateLog="/var/log/packagesupdatefile.log"
if [ -f "$UpdateLog" ]; then
  rm -rf $UpdateLog
fi

apt list --upgradable | awk 'END{print NR}' | tee -a "$UpdateLog" > /dev/null 2>&1
UpdateRemind=`cat $UpdateLog | tail -n 1`
UpdateNum=`expr $UpdateRemind - 1`
if [ "$UpdateNum" -ge "1" ]; then
  printf "$UpdateNum packages can be upgraded. Run 'apt list --upgradable' to see them.\n"
fi

rm -rf $UpdateLog