#!/bin/ksh
#The user's username and the absolute path of the login directory
echo "Your User Name is : $USER"
echo "Your home directory is : $HOME"
#The calendar of 2012
echo "Calendar for 2012 : "
cal 2012
#The total number of files and subdirectories in your login directory
filecount=`ls -l | grep '^-' | wc -l`
echo "Total No. of files in your $HOME directory : $filecount"
dircount=`ls -l | grep '^d' | wc -l`
echo "Total No. of subdirectories in your $HOME directory : $dircount"
#Accept an input of a positive number N that is not greater than 45 (using the read command), and display the first N lines of the contents of Rail-Stations.txt.
echo "Input no. of lines to read from Rail-Stations.txt"
read N
if [ $N -gt 0 ] && [ $N -le 45 ]
then
 head -$N Rail-Stations.txt
else
 echo "$N is either -ve or greater than 45"
fi
 
 
#The long listing of the directory specified by the first command line argument, sorted in reversed alphabetic order.
#If the second command line argument is provided, all the above output will be redirected to the file specified by the second argument. If the second argument is not provided, the above output should be displayed on the screen.
if [ $# -eq 2 ]
then
ls -l *$1* | sort -r > $2
elif [ $# -eq 1 ]
then
ls -l *$1* | sort -r
fi
#Accept the input of a series of lower case alphabetic letters one at a time. The input ends with a 0. Find and display the first letter in alphabetic order and the count of total number of valid input letters
 
Reply=Y
while [ $Reply == 'Y' ] || [ $Reply == 'y' ]
do
        echo "input a series of lower case alphabetic texts one at a time"
        text=a
        >tmp
        until [[ $text = "0" ]]
        do
                read text
                if [ $text == '0' ]
                then
                        break
                fi
                if [ `echo $text | grep '[a-z]'` ]
                then
                        echo $text >> tmp
                else
                        echo "invalid letter"
                fi
        done
echo "first letter"
sort tmp | head -1
echo "count"
wc -l tmp | awk '{print $1}'
 
#Before exit, ask user to confirm by entering a “Y” (“y”) or “N” (“n”). If confirmed, then exit, otherwise, return to the menu
#I am not sure what you mean by menu here, i think there is no point in repeating entire program so just repeating the 2nd taks you mentioned
 
        echo "Want to repeat (y/n) ?"
        read Reply
        if [ $Reply == 'n' ] || [ $Reply == 'N' ]
        then
                exit 0
        fi
done