GTU OS Program - 13 Date Validator
13. Write a shell script to validate the entered date. (eg. Date format is : dd-mm-yyyy).
Complete code of the program
echo "Date validator"
#Initializing values of date, month and year
dd=0
mm=0
yy=0
#initializing no of days in a month
days=0
read -p "Enter day (dd) : " dd
read -p "Enter Month (mm) : " mm
read -p "Enter Year (yyyy) : " yy
#checking for invalid month
if [ $mm -le 0 -o $mm -gt 12 ]
then
echo "$mm is invalid month. "
exit 1
fi
#finding out no. of days in a month
case $mm in
1 | 3 | 5 | 7 | 8 | 10 | 12)
days=31
;;
2)
days=28
;;
4 | 6 | 9 | 11)
days=30
;;
*)
days=-1
;;
esac
#checking for leap year
if [ $mm -eq 2 ]
then
a=`expr $yy % 4`
b=`expr $yy % 100`
c=`expr $yy % 400`
if [ $a -eq 0 -a $b -ne 0 -o $c -eq 0 ]
then
days=29
else
break
fi
fi
if [ $dd -le 0 -o $dd -gt $days ]
then
echo "$dd day is invalid "
exit 3
fi
#No error means date is valid
echo "$dd/$mm/$yy is a Valid Date"
Interpreting the date.sh file and executing it in terminal
tkanu025@hp:~/lab_solutions$ chmod +x date.sh tkanu025@hp:~/lab_solutions$ ./date.sh
Output
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