A leap year comes once every four years. It is the year when an extra day is added to the Gregorian calendar used by most of the world.
An ordinary year has 365 days. A leap year has 366 days. The extra day is added to the month of February. In an ordinary year, February has 28 days. In a leap year, it has 29 days. This extra day is called a leap day.
How do I find out leap year?
A year is a leap year if it can be evenly divided by four. For example, 1996 was a leap year. But a year is not a leap year if can be evenly divided by 100 and not by 400. This is why 1700, 1800, 1900 were not leap years, but 2000 was.
Shell script to determine if entered year is leap or not…
#!/bin/bash # Shell program to read any year and find whether leap year or not # ----------------------------------------------- # Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/> # This script is licensed under GNU GPL version 2.0 or above # ------------------------------------------------------------------------- # This script is part of nixCraft shell script collection (NSSC) # Visit http://bash.cyberciti.biz/ for more information. # ------------------------------------------------------------------------- # store year yy=0 isleap="false" echo -n "Enter year (yyyy) : " read yy # find out if it is a leap year or not if [ $((yy % 4)) -ne 0 ] ; then : # not a leap year : means do nothing and use old value of isleap elif [ $((yy % 400)) -eq 0 ] ; then # yes, it's a leap year isleap="true" elif [ $((yy % 100)) -eq 0 ] ; then : # not a leap year do nothing and use old value of isleap else # it is a leap year isleap="true" fi if [ "$isleap" == "true" ]; then echo "$yy is leap year" else echo "$yy is NOT leap year" fi