Q.1. How to write shell script that will add two nos, which are supplied as command line argument, and if this two nos are not given show error and its usage
#!/bin/bash # Q1.Script to sum to nos # if [ $# -ne 2 ] then echo "Usage - $0 x y" echo " Where x and y are two nos for which I will print sum" exit 1 fi echo "Sum of $1 and $2 is `expr $1 + $2`" #
Q.2.Write Script to find out biggest number from given three nos. Nos are supplies as command line argument. Print error if sufficient arguments are not supplied.
#!/bin/bash # Q2. Script to find out bigest number # # Algo: # 1) START: Take three nos as n1,n2,n3. # 2) Is n1 is greater than n2 and n3, if yes # print n1 is bigest no goto step 5, otherwise goto next step # 3) Is n2 is greater than n1 and n3, if yes # print n2 is bigest no goto step 5, otherwise goto next step # 4) Is n3 is greater than n1 and n2, if yes # print n3 is bigest no goto step 5, otherwise goto next step # 5) END # # if [ $# -ne 3 ] then echo "$0: number1 number2 number3 are not given" >&2 exit 1 fi n1=$1 n2=$2 n3=$3 if [ $n1 -gt $n2 ] && [ $n1 -gt $n3 ] then echo "$n1 is Bigest number" elif [ $n2 -gt $n1 ] && [ $n2 -gt $n3 ] then echo "$n2 is Bigest number" elif [ $n3 -gt $n1 ] && [ $n3 -gt $n2 ] then echo "$n3 is Bigest number" elif [ $1 -eq $2 ] && [ $1 -eq $3 ] && [ $2 -eq $3 ] then echo "All the three numbers are equal" else echo "I can not figure out which number is biger" fi
Q.3.Write script to print nos as 5,4,3,2,1 using while loop.
#!/bin/bash # Q3 # Algo: # 1) START: set value of i to 5 (since we want to start from 5, if you # want to start from other value put that value) # 2) Start While Loop # 3) Chechk, Is value of i is zero, If yes goto step 5 else # continue with next step # 4) print i, decement i by 1 (i.e. i=i-1 to goto zero) and # goto step 3 # 5) END # i=5 while test $i != 0 do echo "$i " i=`expr $i - 1` done
Q.4. Write Script, using case statement to perform basic math operation as follows + addition - subtraction x multiplication / division The name of script must be 'q4' which works as follows $ ./q4 20 / 3, Also check for sufficient command line arguments
#!/bin/bash # Q4 # if test $# = 3 then case $2 in +) let z=$1+$3;; -) let z=$1-$3;; /) let z=$1/$3;; x|X) let z=$1*$3;; *) echo Warning - $2 invalied operator, only +,-,x,/ operator allowed exit;; esac echo Answer is $z else echo "Usage - $0 value1 operator value2" echo " Where, value1 and value2 are numeric values" echo " operator can be +,-,/,x (For Multiplication)" fi
Q.5.Write Script to see current date, time, username, and current directory
#!/bin/bash # Q5 echo "Hello, $LOGNAME" echo "Current date is `date`" echo "User is `who i am`" echo "Current direcotry `pwd`"
Q.6.Write script to print given number in reverse order, for eg. If no is 123 it must print as 321.
#!/bin/bash # Script to reverse given no # # Algo: # 1) Input number n # 2) Set rev=0, sd=0 # 3) Find single digit in sd as n % 10 it will give (left most digit) # 4) Construct revrse no as rev * 10 + sd # 5) Decrment n by 1 # 6) Is n is greater than zero, if yes goto step 3, otherwise next step # 7) Print rev # if [ $# -ne 1 ] then echo "Usage: $0 number" echo " I will find reverse of given number" echo " For eg. $0 123, I will print 321" exit 1 fi n=$1 rev=0 sd=0 while [ $n -gt 0 ] do sd=`expr $n % 10` rev=`expr $rev \* 10 + $sd` n=`expr $n / 10` done echo "Reverse number is $rev"