calcola_stagioni.sh

#!/bin/bash
#Estraggo mese_giorno "MMDD"
mg=`echo $1 | awk -F "/" '{ print $2$1}'`
#Estraggo anno "YYYY"
y=`echo $1 | awk -F "/" '{ print $3}'`

#Lista date stagioni
begin_year=0101
begin_spring=0321
begin_summer=0621
begin_autumn=0923
begin_winter=1221
end_year=1231

#Lista equinozi e solstizi
equ_spring=0321
sol_summer=0621
equ_autumn=0923
sul_winter=1221

#Controlla stagione
if [ $mg -ge $begin_year -a $mg -lt $begin_spring ]; then
  echo "Inverno"
elif [ $mg -ge $begin_spring -a $mg -lt $begin_summer ]; then
  echo "Primavera"
elif [ $mg -ge $begin_summer -a $mg -lt $begin_autumn ]; then
  echo "Estate"
elif [ $mg -ge $begin_autumn -a $mg -lt $begin_winter ]; then
  echo "Autunno"
elif [ $mg -ge $begin_winter -a $mg -lt $end_year ]; then
  echo "Inverno"
fi

#Controlla solstizi o equinozi
if [ $mg -eq $equ_spring ]; then
  echo "Equinozio di primavera"
elif [ $mg -eq $sol_summer ]; then
  echo "Solstizio d'estate"
elif [ $mg -eq $begin_summer ]; then
  echo "Equinozio d'autunno"
elif [ $mg -eq $equ_autumn ]; then
  echo "Solstizio d'inverno"
fi

#Controlla anno bisestile
if (( (y % 400) == 0 )) || (( (y % 4) == 0 && (y % 100) != 0 )); then
  echo "L'anno $anno e' bisestile"
else
  echo "L'anno $anno non e' bisestile"
fi