Playing with shell!

Playing with shell

Here I have summarized few shell script which I routinely use. All the informations are floating in the net. It needs just a little bit of careful google search and then test by yourself.

1. Start with a simple one: Addition, subtraction, multiplication and division 
Let say a=10, b=5, c=a+b or a-b or a/b or a*b. How to do that using Bash (Born Again Shell) shell scripting? However, bash script will give result in integer number.   

a=10
b=5
c=$(($a+$b))
echo $c
It will print 15.

c=$(($a-$b))
echo $c
It will print 5.

c=$(($a/$b))
echo $c It will print 2.
 

c=$(($a*$b))
echo $c
It will print 50.

Let say you would like to do little complex calculation like
 c=(a+b)/a*10 - b/(a-100)
 
c=$(($(($a+$b))/$(($a*10))-$(($b/$(($a-100))))))


1. What if one needs to get the same operation for real numbers? One needs to use then awk script.
a=10.5
b=2.5
c=$(echo $a $b | awk '{ print $1 + $2 }')
echo $c
It will print 13.
 

 c=$(echo $a $b | awk '{ print $1 - $2 }')
echo $c
It will print 8.
 

c=$(echo $a $b | awk '{ print $1 * $2 }')
echo $c
It will print 26.25.
 

c=$(echo $a $b | awk '{ print $1/$2 }')
echo $c
It will print 4.2.