lab4.sh

#! /bin/bash


if(($# != 3));
then
echo "Error! Usage: Season Weekday  YYYY-YYYY ";
exit -1
fi

season=$1
StrDay=$2
season=${season,,}
StrDay=${StrDay,,}

dmy=${3: -o}
set ${dmy//-/' '}

case $season in
"winter") month=12;;
"spring") month=3;;
"summer") month=6;;
"autumn") month=9;;
*) echo "Error. Uncorrect name of the season"
exit -1;;
esac

case $StrDay in
"monday") day=1;;
"tuesday") day=2;;
"wednesday") day=3;;
"thursday") day=4;;
"friday") day=5;;
"saturday") day=6;;
"sunday") day=7;;
*) echo "Error. Uncorrect name of day of the week"
exit -1;;
esac

for((i=$1; i<=$2; i++));
do
  num=`date -d $month/01/$i +"%u"`
  if((num == $day))
  then
    echo $i
  fi
done